Colonic Polypoid Disease: Need for Total Colonoscopy John A. Caller, MD, Boston, Massachusetts Marvin L. Corman, MD, Boston, Massachusetts Malcolm C. Veidenheimer, MD, Boston, Massachusetts
The association of benign colonic neoplastic disease with colonic cancer is well recognized. However, since most neoplastic polyps do not demonstrate a cancerous change and since most cancers fail to demonstrate benign elements, a somewhat ambivalent attitude has been fostered toward the clinical importance of colonic polyp. With the development of fiberoptic colonoscopic technics [1,2], a more aggressive, yet less invasive approach is available for the evaluation and management of colonic polypoid disease. As long-term follow-up studies become available, it should be possible to obtain a more thorough understanding of the natural history of neoplastic polyps and their relationship to colonic cancer. At the present time, colonoscopic evaluation of neoplastic polypoid disease offers an opportunity to examine the reliability of more traditional diagnostic methods and to determine the likelihood of polyp and cancer synchronicity. This report examines the need for endoscopic evaluation of the radiographically suspected benign colonic polyp as well as the need to examine the entire colon when a colonic polyp is encountered. Material and Methods Patient Selection. Patients were included in this analysis if radiographic barium study suggested a single polypoid lesion or, as was true for ten patients, two polypoid lesions. It was required that the radiographic interpretation of the lesion be that of a benign polyp and that the lesion not be accessible with the standard rigid proctosigmoidoscope. Patients with suspected colorectal cancer who were being investigated for synchronous polypoid disease were excluded. Patients suspected of having more than two polypoid lesions on barium enema examination or patients with multiple polyposis syndromes were also
From the
Section of Colon and Rectal Surgery, tahey Clinic Foundation, Boston, Massachusetts. Reprint requests should be addressed to John A. Caller, MD, Section of Colon and Rectal Surgery, Lahey Clinic Foundation, 605 Commonwealth Avenue, Boston, Massachusetts 02215. Presented at the Fifty-Sixth Annwl Meeting of the New England Surgical Society, Portsmouth, New Hampshire, September 25-27. 1975.
490
excluded. Patients with bleeding lesions found by colonoscopic investigation were not included unless barium study had suggested a benign polypoid lesion. Colonoscopic Examination. All colonoscopic examinations were performed by a surgeon experienced in coionic endoscopy. Only patients whose entire colon was examined were included. Some patients had more than one examination. These additional examinations were generally required in the course of treating synchronous polypoid disease or in instances when treatment of a distally located polyp prohibited safe total examination at the time of the initial procedure. Patients being evaluated for colonic polypoid disease are admitted to the hospital to ensure satisfactory coionic cleansing and to enable the safe administration of sufficient analgesia for patient comfort during the examination of the entire colon. Colonic preparation is started on the afternoon of admission at which time a clear liquid diet is prescribed and four bisacodyl (Dulcolax@) tablets are given. In the evening, a colonic saline cleansing irrigation is administered. On the morning of the day of examination, castor oil, 45 ml, is administered and oral hydration is maintained. Approximately 4 to 6 hours later another high colonic saline irrigation is administered. The examination is performed within the next 2 hours. Sedation before examination usually consists of an intramuscular injection of meperidine, 100 mg, and Nembutal@, 100 mg. At the onset of the procedure diazepam (Valium@), 10 mg, is given intravenously with supplemental doses given during the procedure as needed. This regime enables the patient to undergo the examination with little recollection of discomfort but does not eliminate involuntary response to excessive colonic manipulation. The lack of patient discomfort provided by adequate sedation insures patient acceptance. This is important when subsequent examinations may be necessary for colonic polypoid disease. All examinations are performed with the patient on a fluoroscopic table. Although fluoroscopic capacity is not essential during many colonoscopic procedures, it frequently expedites negotiation of the sigmoid and hepatic flexures. Fluoroscopy is, however, vital in the accurate documentation of the location of both suspected and unsuspected polypoid lesions that are encountered during the examination. All examinations were performed with the American Cytoscope Makers Inc (ACMI) F9A two-channel colo-
The American Journal Of Surgery
Colonoscopy for Colonic Polypoids
TABLE
I Colonoscopic Finding at Suspected Site (146 patients)
Number of Patients
Mean
Age W
Radiographic Impression
36
56
Benign
83 10 8
63 64 67
Benign polyp Benign polyps Benign polyp
9
64
Benign polyp
Colonoscopic
...
No lesion
polyp
Benign polyp Benign polyps (2) Polyp with invasion cancer Polypoid or ulcerating adenocarcinoma
(2)
noscope using carbon dioxide insufflation. Snare excision of appropriate polypoid lesions was performed with the ACM1 Pneumotone-200 electrosurgical unit. Histopathology of Polypoid Lesions. Only lesions that were submitted to complete histopathologic examination, either after colonoscopic removal or subsequent resection, were included in this analysis. Polyps that were not removed or that were not recovered after removal were not included. Furthermore, only neoplastic lesions arising from colonic epithelium were considered. Mucosal excrescences, hyperplastic polyps, inflammatory polyps, and lipomas were not included. The histologic criteria of neoplastic polyps is essentially that described by Morson and Dawson [3]. Adenomas, papillary adenomas, or villous papillomas containing cytologic carcinomatous change not yet invading the muscularis mucosa are classified as benign polyps. A neoplastic polyp with invasive carcinoma is one in which the cancerous change has breached the muscularis mucosa. A polypoid carcinoma is an exophytic lesion that is entirely cancerous, with no histologic evidence of residual or accompanying benign neoplasia. Colonoscopic Finding at Site of Radiographically Suspected Polyp. Colonoscopic examination of the entire colon was performed in 146 patients because of the radiographically suspected presence of a single benign polyp in 136 patients and because of two benign polyps suspected in 10 patients. Thirty-six patients did not have a lesion at the site of the radiographically suspected polyp. One hundred ten patients had a neoplastic lesion at the radiographically suspected site. A benign neoplastic polyp was found in 83 of these 110 patients, and two benign neoplastic polyps were found in each of the 10 patients suspected of having multiple polyps. Eight patients had a neoplastic polyp with invasive carcinoma, and nine patients had either a polypoid or an ulcerating adenocarcinoma at the site of a suspected benign polypoid lesion on the radiograph. The mean age of patients and lesion diameter for each group of patients are given in Table I. Only one of the eight patients with a polyp containing invasive carcinoma underwent subsequent resection. Residual cancer or lymphatic metastasis was not evident in the resected specimen. All nine patients with polypoid or ulcerating adenocarcinoma underwent subse-
volunw 131, April lB76
Diameter (cm + 1 SD)
Finding
1.69 + 0.81 1.46 + 0.87 1.96 + 0.37 1.88 i- 0.40
went resection. The lesion was located in the sigmoid in five patients, in the distal descending colon in three patients, and in the midascending colon in one patient. One patient with an ulcerating adenocarcinoma and two patients with polypoid adenocarcinomas had lymphatic metastases (Dukes’ Stage C). The remaining five patients were classified as having Dukes’ Stage A disease. Mean size of the lesion in these nine patients was 1.88 f 0.40 cm (range, 1.2 to 2.5 cm). Additional Unsuspected Polyps Found During Total Colonoscopy. In addition to the lesions that were suspected from the barium examination and subsequently found by colonoscopy, 141 neoplastic lesions that had not been suspected on radiographic examination were found by colonoscopy. Of the thirty-six patients who did not have a polyp even though the barium study suggested a polyp, seven (19 per cent) were found to have an unsuspected polyp elsewhere in the colon. In each instance the polyp was a small (0.3 to 0.6 cm) benign polypoid adenoma. In contrast, 132 additional neoplastic lesions were found in 62 of the 110 patients (56 per cent) who had a polyp or cancer at the site of the suspected benign polyp by barium enema study. (Table II.) The majority of these additional unsuspected neoplastic polyps were found proximal to the polyp that was suspected on the radiographic study. Of the additional unsuspected polyps 66 per cent were located proximal to the splenic flexure, whereas only 18 per cent of the radiographically suspected lesions were above the splenic flexure. Table III shows the frequency of finding additional unsuspected polyps and a description of those patients with cancer.
Comments Suspected
Polyp.
Of 146 patients
suspected
of
having a total of 156 polyps on radiographic examination, 36 polyps were not present, giving a radio-
graphic false-positive rate of 23 per cent. One hundred twenty neoplastic lesions that were suspected and 141 that were not suspected by barium study were found during colonoscopic examination, giving a radiographic false-negative rate of 54 per cent.
This
is a rather
harsh
comparison
and must
491
Caller, Corman,
TABLE
and Veidenheimer
I I Additional
Unsuspected
Colonoscopic
Findings Additional Unsuspected Findings
Number of Patients 36
No lesion Lesion
110
TABLE
Colonoscopic Finding at Suspected Site
I II
Additional
Average Age (vr)
Number of Patients
55.5 63.3
7 (19%) 62 (56%)
Unsuspected
(e9.6) (*8.8)
Polyps
Found
Neoplastic Lesions Number
Size (cm)
9 132
0.52 0.94
Number with Cancer
(t0.12) (kO.63)
None 6 (5 patients)
with Colonoscopy Additional Polyps Found
Number Patients 83 10 8 9
Colonoscopic Finding at Suspected Site Benign polyp Benign polyps (2) Polyps with invasive cancer Polypoid or ulcerating adenocarcinema
110
Number of Patients
adenoma
Number with Cancer
75 36 9
4 patients* None None
5 (56%)
12
1 patient 3.2 cm adenocarcinema, stage A, and 1.1 cm polypoid adenoma with invasive carcinoma
62 (56%)
132
Stage A; 1.2 cm polypoid with invasive carcinoma.
be tempered by our evolving criteria for performing a colonoscopic examination for radiographically suspected colonic polypoid disease. The primary objective of this analysis was not to evaluate the sensitivity of barium enema study or air contrast examination. Although most patients had multiple radiographic studies, frequently additional studies were not believed warranted when an initial examination of satisfactory quality strongly suggested the need for endoscopic evaluation. Usually, if the barium study created enough suspicion of polypoid disease to suggest that endoscopy was indicated, colonoscopy was performed without further radiographic examination. No remarkable difference existed in the number of radiographic examinations that preceded colonoscopy in the group of thirty-six patients who did not have the suspected polyp compared with the patients who did have a polyp at the suspected site. However, the criteria for performing colonoscopic examination in pursuit of polypoid disease are not as rigid as the criteria when laparotomy was the major treatment modality. Although the mean patient age for the group without a polyp at the suspected site was less than the mean age of the remaining 110 patients, this 492
Number
42 (51%) 10 (100%) 5 (63%)
*3.5 cm adenocarcinoma, Dukes’ C; and 0.6 cm polypoid
Neoplasms
adenocarcinoma,
Stage A; 1.0 cm adenocarcinoma,
Stage
difference was not statistically significant. In contrast to the patients in whom a lesion was present at the suspected site, a large portion of the thirtysix patients were being investigated for suspected cecal lesions; these lesions were determined to be ileocecal valve abnormalities not of neoplastic origin. The two main criteria used to suggest benignity on radiographic examination of colonic polypoid disease were the presence of pedunculation and small polyp size. Although pedunculation may bear some relationship to the clinical importance of invasive cancer and therapeutic requirement, it does not appear to be a factor in preventing the secondary development of cancer in the substance of the polyp. Although a pedicle may, on teleologic grounds, afford a degree of protection by keeping the developing cancer remote from the bowel wall for a period of time, the inception of invasive cancer appears to be more a function of the adenomatous tissue than of the attachment of the adenomatous structure to the bowel wall. In eight patients who were suspected of having a benign polypoid lesion but instead had polyps with invasive cancer, the pedicles ranged from 0.5 to 4.0 cm in length.
The American Journal of Surgery
Colonoscopy for Colonic Polypoids
The size of a polyp as observed on radiographic study has some relationship to the likelihood of the presence of invasive cancer. However, the overlap in polyp size is so broad that it is not possible to make a meaningful or reliable prediction of the presence of invasive cancer on the basis of size. (Table I.) The mean diameter of the suspected polyp in the eighty-three patients in whom a single polyp was suspected and a benign polyp was found was 1.69 cm f 0.81. The lesion was slightly larger in the eight patients found to have a polyp with invasive cancer: 1.96 cm f 0.37. In the nine patients found to have polypoid or ulcerating adenocarcinoma, the lesion was 1.88 cm f 0.40. Because of this broad range, size is not an appropriate indicator upon which to make a therapeutic decision. Of 110 patients in whom polyps were suspected by radiographic examination, 17 (15 per cent) patients had polypoid lesions with invasive cancer or polypoid or ulcerating cancer rather than the anticipated benign lesion. All of .the nine patients with polypoid or ulcerating cancer underwent resection, three (33 per cent) of whom were found to have regional lymph node metastases. Unsuspected Polyps. Among the thirty-six patients who failed to have a polyp at the suspected site, seven (19 per cent) had an unsuspected polyp elsewhere in the colon. In each instance the unsuspected polyp was morphologically a mucosal elevation of small size, ranging from 0.3 to 0.6 cm. Histologic examination revealed each of these polyps to be a benign polypoid adenoma. Since the polyp for which the examination was undertaken was not present, this group serves, to some degree, as a control population for the remaining patients in terms of the expected incidence of neoplastic polyps* .If the suspected neoplastic polyp is present, the likelihood of finding additional unsuspected polyps is quite high; more than half the patients who had a neoplastic lesion at the suspected site had additional unsuspected polyps elsewhere in the colon. All of the ten patients who were suspected of having two polyps had additional unsuspected neoplastic polyps. The mean diameter of the unsuspected polyps (Table II) was considerably smaller than that observed for the radiographically detected lesion. Although the majority of the unsuspected polyps were benign neoplastic lesions, five patients had either polypoid or ulcerating adenocarcinoma or a polypoid adenoma with invasive carcinoma. In each patient, the malignant lesion was proximal to the polyp that was suspected on radiographic veknw
1a1,
April
1078
SlGMOlD
DESCENDING COLON
TRANSVERSE
ASCENDING
CECUM
SEGMENT
Figure 1. Location of neoplaatk co/o&
lesions.
study. The smallest of these histologically malignant lesions was a 0.6 cm polypoid adenoma with invasive carcinoma in the descending colon. Another patient with a 1.0 cm polypoid adenocarcinoma of the descending colon was found to have lymph node metastases on subsequent resection. In two other patients a 1.2 cm polypoid adenocarcinema of the proximal sigmoid colon and a 3.5 cm ulcerating adenocarcinoma of the descending colon were both Stage A lesions. One patient who had an ulcerating adenocarcinoma of the descending colon (at the site of a suspected lesion) was also found to have an unsuspected 3.2 cm adenocarcinoma, Stage A, of the ascending colon and a 1.1 cm polypoid adenoma with invasive carcinoma in the transverse colon. When it is recalled that 17 of the 110 patients (15 per cent) in whom a lesion was found at the suspected site had a malignant lesion, the addition of the 4 patients just described with benign polyps at the suspected site but who had additional unsuspected malignant lesions elsewhere in the colon gives a total of 21 patients (19 per cent) found to have a malignant lesion as a result of total colonoscopic examination. The anatomic distribution of the lesions detected by radiographic examination was centered in the sigmoid and descending colon. Only 18 per cent of the polyps were proximal to the splenic flexure. However, 66 per cent of the additional unsuspected neoplastic lesions were found proximal to the splenic flexure, resulting in a more uniform distribution of neoplastic colonic polypoid disease. (Figure 1.) Although it is apparent that the anatomic distribution of the malignant lesions paralleled that seen for the radiographically suspected polyp, it is important to recognize that most of the unsuspected benign neoplasms and all of the un493
Caller, Corman, and Veidenheimer
suspected malignant neoplasms were found proximal to the site of the suspected polyp. Summary
Colonoscopic examination of the entire colon was performed on 146 patients for radiographically suspected benign polypoid disease. Of thirty-six patients who did not have a neoplastic lesion at the suspected site, seven (19 per cent) had unsuspected small benign polypoid adenomas elsewhere in the colon. Of the remaining 110 patients who had a neoplastic lesion at the radiographically suspected site, 17 lesions (15 per cent) were either adenocarcinemas or neoplastic polyps with invasive carcinoma. One hundred twenty-eight additional unsuspected neoplastic polyps were found in 62 of the 110 patients (56 per cent). Six of the additional neoplastic lesions were either adenocarcinomas or polyps with invasive carcinoma. Four of these malignant lesions were in patients who had a benign polyp at the radiographically suspected site. Suspected colonic polypoid disease should be evaluated colonoscopically despite radiographic evidence of benignity. Colonoscopic evaluation in colonic polypoid disease should include examination of the entire colon with pathologic documentation of all polypoid lesions encountered. Acknowledgment: We wish to thank Merle A. Legg, MD, and Roger C. Haggitt, MD, Laboratory of Pathology, New England Deaconess Hospital, Boston, for their help in reviewing the pathologic material. References 1. Overholt BF: Flexible fiberoptic sigmoidoscopy. Technique and preliminary results. Cancer 28: 123, 1971. 2. Wolff WI, Shinya H: Polypectomy via the fiberoptic colonoscope. Removal of neoplasm beyond reach of the sigmoidoscope. N Engl J Med 288: 329, 1973. 3. Morson BC, Dawson IMP: Gastrointestinal Pathology. Oxford, Blackwell, 1972, p 539.
Discussion
Charles N. Peabody (Framingham, MA): What goes for benign lesions certainly goes for patients who have carcinoma of the colon. Several years ago we reviewed 100 segments of colon removed at time of operation for cancer and had the same experience of finding, in 25 per cent, additional unsuspected polyoid lesions. Of these unsuspected lesions that were found, 30 per cent were a second carcinoma, many of which were very close to the line of resection.
494
The authors have shown us how to identify and detect polyps and I want to know if they were as successful in removing them. The alternative to removing these lesions endoscopically is transrectal polypectomy and laparotomy for hand guidance of the metal sigmoidoscope . which avoids the problem of sepsis. I have had occasion to use this technic in six instances and have been surprised that my experience has been the same as that of the authors. In half the patients I found additional lesions. Stephen E. Hedberg (Boston, MA): A number of questions are raised, not the least provocative of which is why lesions seen on x-ray film and thought benign are much more often malignant than is the average colonic polyp removed with the colonoscope. The explanation for this apparent paradox lies in the fact that smaller lesions tend to be overlooked on x-ray film, whereas larger lesions tend more often to be malignant. These facts are supported by Shinya’s report on 284 polyps, Williams series, and our own series of 625 polyps. In our series at Massachusetts General Hospital, there were forty-three polyps containing carcinoma-twenty sessile and twenty-three pedunculated. Of the 626 polyps, 63 per cent were seen on x-ray film, whereas 85 per cent of sessile and 91 per cent of pedunculated malignant polyps were seen on x-ray film. Only one of the twenty-one pedunculated malignant polyps seen on x-ray film was suspected to be malignant. Thus, we can explain the paradox presented by the authors: malignant polyps are much more apt to be seen on x-ray film than benign polyps, but the radiologist is usually wrong in his predictions of benignancy. My final point is perhaps a bit off the subject, but it is important to remark that in our series the incidence of lymph node metastasis in patients who came to surgery was great. Even in the nine patients with pedunculated lesions, five (44 per cent) had lymph node metastasis. On the basis of our series, we are left with two admonitions that also emerge from the authors’ statistics perhaps a bit less explicitly. The first is: regard with suspicion the radiologist’s diagnosis of benignancy with respect to a visualized colonic polyp. The second is: beware of the metastatic potential of the polyp containing carcinoma. Invasive lesions whether sessile or pedunculated frequently metastasize to regional lymph nodes. Segmental resection of the colon should be recommended in the majority of good risk patients with carcinomas invasive of the muscularis mucosa. John R. Brooks (Boston, MA): I would just like to ask one question of Doctor Coller. Given a person in whom you find an adenomatous polyp, say 30 cm or perhaps greater, what is your plan of action from there on? How do you follow that individual? Do you perform colonoscopy every six months? Do you perform a barium enema every six months? How do you handle a patient after you have found an adenomatous polyp?
The American Journal
01
Surgery
The association of benign colonic neoplastic disease with colonic cancer is well recognized. However, since most neoplastic polyps do not demonstrate a cancerous change and since most cancers fail to demonstrate benign elements, a somewhat ambivalent attitude has been fostered toward the clinical importance of colonic polyp. With the development of fiberoptic colonoscopic technics [1,2], a more aggressive, yet less invasive approach is available for the evaluation and management of colonic polypoid disease. As long-term follow-up studies become available, it should be possible to obtain a more thorough understanding of the natural history of neoplastic polyps and their relationship to colonic cancer. At the present time, colonoscopic evaluation of neoplastic polypoid disease offers an opportunity to examine the reliability of more traditional diagnostic methods and to determine the likelihood of polyp and cancer synchronicity. This report examines the need for endoscopic evaluation of the radiographically suspected benign colonic polyp as well as the need to examine the entire colon when a colonic polyp is encountered. Material and Methods Patient Selection. Patients were included in this analysis if radiographic barium study suggested a single polypoid lesion or, as was true for ten patients, two polypoid lesions. It was required that the radiographic interpretation of the lesion be that of a benign polyp and that the lesion not be accessible with the standard rigid proctosigmoidoscope. Patients with suspected colorectal cancer who were being investigated for synchronous polypoid disease were excluded. Patients suspected of having more than two polypoid lesions on barium enema examination or patients with multiple polyposis syndromes were also
From the
Section of Colon and Rectal Surgery, tahey Clinic Foundation, Boston, Massachusetts. Reprint requests should be addressed to John A. Caller, MD, Section of Colon and Rectal Surgery, Lahey Clinic Foundation, 605 Commonwealth Avenue, Boston, Massachusetts 02215. Presented at the Fifty-Sixth Annwl Meeting of the New England Surgical Society, Portsmouth, New Hampshire, September 25-27. 1975.
490
excluded. Patients with bleeding lesions found by colonoscopic investigation were not included unless barium study had suggested a benign polypoid lesion. Colonoscopic Examination. All colonoscopic examinations were performed by a surgeon experienced in coionic endoscopy. Only patients whose entire colon was examined were included. Some patients had more than one examination. These additional examinations were generally required in the course of treating synchronous polypoid disease or in instances when treatment of a distally located polyp prohibited safe total examination at the time of the initial procedure. Patients being evaluated for colonic polypoid disease are admitted to the hospital to ensure satisfactory coionic cleansing and to enable the safe administration of sufficient analgesia for patient comfort during the examination of the entire colon. Colonic preparation is started on the afternoon of admission at which time a clear liquid diet is prescribed and four bisacodyl (Dulcolax@) tablets are given. In the evening, a colonic saline cleansing irrigation is administered. On the morning of the day of examination, castor oil, 45 ml, is administered and oral hydration is maintained. Approximately 4 to 6 hours later another high colonic saline irrigation is administered. The examination is performed within the next 2 hours. Sedation before examination usually consists of an intramuscular injection of meperidine, 100 mg, and Nembutal@, 100 mg. At the onset of the procedure diazepam (Valium@), 10 mg, is given intravenously with supplemental doses given during the procedure as needed. This regime enables the patient to undergo the examination with little recollection of discomfort but does not eliminate involuntary response to excessive colonic manipulation. The lack of patient discomfort provided by adequate sedation insures patient acceptance. This is important when subsequent examinations may be necessary for colonic polypoid disease. All examinations are performed with the patient on a fluoroscopic table. Although fluoroscopic capacity is not essential during many colonoscopic procedures, it frequently expedites negotiation of the sigmoid and hepatic flexures. Fluoroscopy is, however, vital in the accurate documentation of the location of both suspected and unsuspected polypoid lesions that are encountered during the examination. All examinations were performed with the American Cytoscope Makers Inc (ACMI) F9A two-channel colo-
The American Journal Of Surgery
Colonoscopy for Colonic Polypoids
TABLE
I Colonoscopic Finding at Suspected Site (146 patients)
Number of Patients
Mean
Age W
Radiographic Impression
36
56
Benign
83 10 8
63 64 67
Benign polyp Benign polyps Benign polyp
9
64
Benign polyp
Colonoscopic
...
No lesion
polyp
Benign polyp Benign polyps (2) Polyp with invasion cancer Polypoid or ulcerating adenocarcinoma
(2)
noscope using carbon dioxide insufflation. Snare excision of appropriate polypoid lesions was performed with the ACM1 Pneumotone-200 electrosurgical unit. Histopathology of Polypoid Lesions. Only lesions that were submitted to complete histopathologic examination, either after colonoscopic removal or subsequent resection, were included in this analysis. Polyps that were not removed or that were not recovered after removal were not included. Furthermore, only neoplastic lesions arising from colonic epithelium were considered. Mucosal excrescences, hyperplastic polyps, inflammatory polyps, and lipomas were not included. The histologic criteria of neoplastic polyps is essentially that described by Morson and Dawson [3]. Adenomas, papillary adenomas, or villous papillomas containing cytologic carcinomatous change not yet invading the muscularis mucosa are classified as benign polyps. A neoplastic polyp with invasive carcinoma is one in which the cancerous change has breached the muscularis mucosa. A polypoid carcinoma is an exophytic lesion that is entirely cancerous, with no histologic evidence of residual or accompanying benign neoplasia. Colonoscopic Finding at Site of Radiographically Suspected Polyp. Colonoscopic examination of the entire colon was performed in 146 patients because of the radiographically suspected presence of a single benign polyp in 136 patients and because of two benign polyps suspected in 10 patients. Thirty-six patients did not have a lesion at the site of the radiographically suspected polyp. One hundred ten patients had a neoplastic lesion at the radiographically suspected site. A benign neoplastic polyp was found in 83 of these 110 patients, and two benign neoplastic polyps were found in each of the 10 patients suspected of having multiple polyps. Eight patients had a neoplastic polyp with invasive carcinoma, and nine patients had either a polypoid or an ulcerating adenocarcinoma at the site of a suspected benign polypoid lesion on the radiograph. The mean age of patients and lesion diameter for each group of patients are given in Table I. Only one of the eight patients with a polyp containing invasive carcinoma underwent subsequent resection. Residual cancer or lymphatic metastasis was not evident in the resected specimen. All nine patients with polypoid or ulcerating adenocarcinoma underwent subse-
volunw 131, April lB76
Diameter (cm + 1 SD)
Finding
1.69 + 0.81 1.46 + 0.87 1.96 + 0.37 1.88 i- 0.40
went resection. The lesion was located in the sigmoid in five patients, in the distal descending colon in three patients, and in the midascending colon in one patient. One patient with an ulcerating adenocarcinoma and two patients with polypoid adenocarcinomas had lymphatic metastases (Dukes’ Stage C). The remaining five patients were classified as having Dukes’ Stage A disease. Mean size of the lesion in these nine patients was 1.88 f 0.40 cm (range, 1.2 to 2.5 cm). Additional Unsuspected Polyps Found During Total Colonoscopy. In addition to the lesions that were suspected from the barium examination and subsequently found by colonoscopy, 141 neoplastic lesions that had not been suspected on radiographic examination were found by colonoscopy. Of the thirty-six patients who did not have a polyp even though the barium study suggested a polyp, seven (19 per cent) were found to have an unsuspected polyp elsewhere in the colon. In each instance the polyp was a small (0.3 to 0.6 cm) benign polypoid adenoma. In contrast, 132 additional neoplastic lesions were found in 62 of the 110 patients (56 per cent) who had a polyp or cancer at the site of the suspected benign polyp by barium enema study. (Table II.) The majority of these additional unsuspected neoplastic polyps were found proximal to the polyp that was suspected on the radiographic study. Of the additional unsuspected polyps 66 per cent were located proximal to the splenic flexure, whereas only 18 per cent of the radiographically suspected lesions were above the splenic flexure. Table III shows the frequency of finding additional unsuspected polyps and a description of those patients with cancer.
Comments Suspected
Polyp.
Of 146 patients
suspected
of
having a total of 156 polyps on radiographic examination, 36 polyps were not present, giving a radio-
graphic false-positive rate of 23 per cent. One hundred twenty neoplastic lesions that were suspected and 141 that were not suspected by barium study were found during colonoscopic examination, giving a radiographic false-negative rate of 54 per cent.
This
is a rather
harsh
comparison
and must
491
Caller, Corman,
TABLE
and Veidenheimer
I I Additional
Unsuspected
Colonoscopic
Findings Additional Unsuspected Findings
Number of Patients 36
No lesion Lesion
110
TABLE
Colonoscopic Finding at Suspected Site
I II
Additional
Average Age (vr)
Number of Patients
55.5 63.3
7 (19%) 62 (56%)
Unsuspected
(e9.6) (*8.8)
Polyps
Found
Neoplastic Lesions Number
Size (cm)
9 132
0.52 0.94
Number with Cancer
(t0.12) (kO.63)
None 6 (5 patients)
with Colonoscopy Additional Polyps Found
Number Patients 83 10 8 9
Colonoscopic Finding at Suspected Site Benign polyp Benign polyps (2) Polyps with invasive cancer Polypoid or ulcerating adenocarcinema
110
Number of Patients
adenoma
Number with Cancer
75 36 9
4 patients* None None
5 (56%)
12
1 patient 3.2 cm adenocarcinema, stage A, and 1.1 cm polypoid adenoma with invasive carcinoma
62 (56%)
132
Stage A; 1.2 cm polypoid with invasive carcinoma.
be tempered by our evolving criteria for performing a colonoscopic examination for radiographically suspected colonic polypoid disease. The primary objective of this analysis was not to evaluate the sensitivity of barium enema study or air contrast examination. Although most patients had multiple radiographic studies, frequently additional studies were not believed warranted when an initial examination of satisfactory quality strongly suggested the need for endoscopic evaluation. Usually, if the barium study created enough suspicion of polypoid disease to suggest that endoscopy was indicated, colonoscopy was performed without further radiographic examination. No remarkable difference existed in the number of radiographic examinations that preceded colonoscopy in the group of thirty-six patients who did not have the suspected polyp compared with the patients who did have a polyp at the suspected site. However, the criteria for performing colonoscopic examination in pursuit of polypoid disease are not as rigid as the criteria when laparotomy was the major treatment modality. Although the mean patient age for the group without a polyp at the suspected site was less than the mean age of the remaining 110 patients, this 492
Number
42 (51%) 10 (100%) 5 (63%)
*3.5 cm adenocarcinoma, Dukes’ C; and 0.6 cm polypoid
Neoplasms
adenocarcinoma,
Stage A; 1.0 cm adenocarcinoma,
Stage
difference was not statistically significant. In contrast to the patients in whom a lesion was present at the suspected site, a large portion of the thirtysix patients were being investigated for suspected cecal lesions; these lesions were determined to be ileocecal valve abnormalities not of neoplastic origin. The two main criteria used to suggest benignity on radiographic examination of colonic polypoid disease were the presence of pedunculation and small polyp size. Although pedunculation may bear some relationship to the clinical importance of invasive cancer and therapeutic requirement, it does not appear to be a factor in preventing the secondary development of cancer in the substance of the polyp. Although a pedicle may, on teleologic grounds, afford a degree of protection by keeping the developing cancer remote from the bowel wall for a period of time, the inception of invasive cancer appears to be more a function of the adenomatous tissue than of the attachment of the adenomatous structure to the bowel wall. In eight patients who were suspected of having a benign polypoid lesion but instead had polyps with invasive cancer, the pedicles ranged from 0.5 to 4.0 cm in length.
The American Journal of Surgery
Colonoscopy for Colonic Polypoids
The size of a polyp as observed on radiographic study has some relationship to the likelihood of the presence of invasive cancer. However, the overlap in polyp size is so broad that it is not possible to make a meaningful or reliable prediction of the presence of invasive cancer on the basis of size. (Table I.) The mean diameter of the suspected polyp in the eighty-three patients in whom a single polyp was suspected and a benign polyp was found was 1.69 cm f 0.81. The lesion was slightly larger in the eight patients found to have a polyp with invasive cancer: 1.96 cm f 0.37. In the nine patients found to have polypoid or ulcerating adenocarcinoma, the lesion was 1.88 cm f 0.40. Because of this broad range, size is not an appropriate indicator upon which to make a therapeutic decision. Of 110 patients in whom polyps were suspected by radiographic examination, 17 (15 per cent) patients had polypoid lesions with invasive cancer or polypoid or ulcerating cancer rather than the anticipated benign lesion. All of .the nine patients with polypoid or ulcerating cancer underwent resection, three (33 per cent) of whom were found to have regional lymph node metastases. Unsuspected Polyps. Among the thirty-six patients who failed to have a polyp at the suspected site, seven (19 per cent) had an unsuspected polyp elsewhere in the colon. In each instance the unsuspected polyp was morphologically a mucosal elevation of small size, ranging from 0.3 to 0.6 cm. Histologic examination revealed each of these polyps to be a benign polypoid adenoma. Since the polyp for which the examination was undertaken was not present, this group serves, to some degree, as a control population for the remaining patients in terms of the expected incidence of neoplastic polyps* .If the suspected neoplastic polyp is present, the likelihood of finding additional unsuspected polyps is quite high; more than half the patients who had a neoplastic lesion at the suspected site had additional unsuspected polyps elsewhere in the colon. All of the ten patients who were suspected of having two polyps had additional unsuspected neoplastic polyps. The mean diameter of the unsuspected polyps (Table II) was considerably smaller than that observed for the radiographically detected lesion. Although the majority of the unsuspected polyps were benign neoplastic lesions, five patients had either polypoid or ulcerating adenocarcinoma or a polypoid adenoma with invasive carcinoma. In each patient, the malignant lesion was proximal to the polyp that was suspected on radiographic veknw
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study. The smallest of these histologically malignant lesions was a 0.6 cm polypoid adenoma with invasive carcinoma in the descending colon. Another patient with a 1.0 cm polypoid adenocarcinoma of the descending colon was found to have lymph node metastases on subsequent resection. In two other patients a 1.2 cm polypoid adenocarcinema of the proximal sigmoid colon and a 3.5 cm ulcerating adenocarcinoma of the descending colon were both Stage A lesions. One patient who had an ulcerating adenocarcinoma of the descending colon (at the site of a suspected lesion) was also found to have an unsuspected 3.2 cm adenocarcinoma, Stage A, of the ascending colon and a 1.1 cm polypoid adenoma with invasive carcinoma in the transverse colon. When it is recalled that 17 of the 110 patients (15 per cent) in whom a lesion was found at the suspected site had a malignant lesion, the addition of the 4 patients just described with benign polyps at the suspected site but who had additional unsuspected malignant lesions elsewhere in the colon gives a total of 21 patients (19 per cent) found to have a malignant lesion as a result of total colonoscopic examination. The anatomic distribution of the lesions detected by radiographic examination was centered in the sigmoid and descending colon. Only 18 per cent of the polyps were proximal to the splenic flexure. However, 66 per cent of the additional unsuspected neoplastic lesions were found proximal to the splenic flexure, resulting in a more uniform distribution of neoplastic colonic polypoid disease. (Figure 1.) Although it is apparent that the anatomic distribution of the malignant lesions paralleled that seen for the radiographically suspected polyp, it is important to recognize that most of the unsuspected benign neoplasms and all of the un493
Caller, Corman, and Veidenheimer
suspected malignant neoplasms were found proximal to the site of the suspected polyp. Summary
Colonoscopic examination of the entire colon was performed on 146 patients for radiographically suspected benign polypoid disease. Of thirty-six patients who did not have a neoplastic lesion at the suspected site, seven (19 per cent) had unsuspected small benign polypoid adenomas elsewhere in the colon. Of the remaining 110 patients who had a neoplastic lesion at the radiographically suspected site, 17 lesions (15 per cent) were either adenocarcinemas or neoplastic polyps with invasive carcinoma. One hundred twenty-eight additional unsuspected neoplastic polyps were found in 62 of the 110 patients (56 per cent). Six of the additional neoplastic lesions were either adenocarcinomas or polyps with invasive carcinoma. Four of these malignant lesions were in patients who had a benign polyp at the radiographically suspected site. Suspected colonic polypoid disease should be evaluated colonoscopically despite radiographic evidence of benignity. Colonoscopic evaluation in colonic polypoid disease should include examination of the entire colon with pathologic documentation of all polypoid lesions encountered. Acknowledgment: We wish to thank Merle A. Legg, MD, and Roger C. Haggitt, MD, Laboratory of Pathology, New England Deaconess Hospital, Boston, for their help in reviewing the pathologic material. References 1. Overholt BF: Flexible fiberoptic sigmoidoscopy. Technique and preliminary results. Cancer 28: 123, 1971. 2. Wolff WI, Shinya H: Polypectomy via the fiberoptic colonoscope. Removal of neoplasm beyond reach of the sigmoidoscope. N Engl J Med 288: 329, 1973. 3. Morson BC, Dawson IMP: Gastrointestinal Pathology. Oxford, Blackwell, 1972, p 539.
Discussion
Charles N. Peabody (Framingham, MA): What goes for benign lesions certainly goes for patients who have carcinoma of the colon. Several years ago we reviewed 100 segments of colon removed at time of operation for cancer and had the same experience of finding, in 25 per cent, additional unsuspected polyoid lesions. Of these unsuspected lesions that were found, 30 per cent were a second carcinoma, many of which were very close to the line of resection.
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The authors have shown us how to identify and detect polyps and I want to know if they were as successful in removing them. The alternative to removing these lesions endoscopically is transrectal polypectomy and laparotomy for hand guidance of the metal sigmoidoscope . which avoids the problem of sepsis. I have had occasion to use this technic in six instances and have been surprised that my experience has been the same as that of the authors. In half the patients I found additional lesions. Stephen E. Hedberg (Boston, MA): A number of questions are raised, not the least provocative of which is why lesions seen on x-ray film and thought benign are much more often malignant than is the average colonic polyp removed with the colonoscope. The explanation for this apparent paradox lies in the fact that smaller lesions tend to be overlooked on x-ray film, whereas larger lesions tend more often to be malignant. These facts are supported by Shinya’s report on 284 polyps, Williams series, and our own series of 625 polyps. In our series at Massachusetts General Hospital, there were forty-three polyps containing carcinoma-twenty sessile and twenty-three pedunculated. Of the 626 polyps, 63 per cent were seen on x-ray film, whereas 85 per cent of sessile and 91 per cent of pedunculated malignant polyps were seen on x-ray film. Only one of the twenty-one pedunculated malignant polyps seen on x-ray film was suspected to be malignant. Thus, we can explain the paradox presented by the authors: malignant polyps are much more apt to be seen on x-ray film than benign polyps, but the radiologist is usually wrong in his predictions of benignancy. My final point is perhaps a bit off the subject, but it is important to remark that in our series the incidence of lymph node metastasis in patients who came to surgery was great. Even in the nine patients with pedunculated lesions, five (44 per cent) had lymph node metastasis. On the basis of our series, we are left with two admonitions that also emerge from the authors’ statistics perhaps a bit less explicitly. The first is: regard with suspicion the radiologist’s diagnosis of benignancy with respect to a visualized colonic polyp. The second is: beware of the metastatic potential of the polyp containing carcinoma. Invasive lesions whether sessile or pedunculated frequently metastasize to regional lymph nodes. Segmental resection of the colon should be recommended in the majority of good risk patients with carcinomas invasive of the muscularis mucosa. John R. Brooks (Boston, MA): I would just like to ask one question of Doctor Coller. Given a person in whom you find an adenomatous polyp, say 30 cm or perhaps greater, what is your plan of action from there on? How do you follow that individual? Do you perform colonoscopy every six months? Do you perform a barium enema every six months? How do you handle a patient after you have found an adenomatous polyp?
The American Journal
01
Surgery
