0306~3016/79/0701~0935/502

(Xl/O

l Original Contribution

THE EFFECT OF PELVIC IRRADIATION ABSORPTION OF BILE ACIDS JOHN A. STRYKER, M.D.” The Departments

ON THE

and LAURENCE M. DEMERS, Ph.D.’

of Radiology” and Pathologyh, of the Milton S. Hershey Medical Pennsylvania State University, Hershey, PA 17033, U.S.A.

Center

of the

The pathophysiology of radiation-induced diarrhea was evaluated in 17 patients undergoing pelvic irradiation for gynecological malignancies. The glycine conjugates of cholic acid (GC) and chenodeoxycholic acid (GCDC) were measured in serum by radioimmunoassay. Fasting and 2 hr post prandial (pp) determinations were performed prior to and in the fifth week of radiotherapy. The pre-treatment fasting and 2 hr pp GC levels were 0.20? 0.29 (mean +- SD) and 0.48 2 0.47 PM. In the fifth week the fasting and 2 hr pp CC levels were 0.16 5 0.23 and 0.25 ? 0.27 PM. The first week fasting and 2 hr pp GCDC levels were 0.32 + 0.47 and 0.80? 0.83 ).LM: in the fifth week they were 0.1050.06 and 0.33kO.27 PM. The differences between the first and the fifth week post prandial increases in serum GC and GCDC levels were significant (P < 0.02). The reduced post prandial increases in serum GC and GCDC in the fifth week of radiotherapy occurred at a time when the patients’ daily stool frequencies were significantly increased (P < 0.01). The data suggest that a cholerrheic enterouathy is the major determinant in the pathophysiology of radiation-induced diarrhea. YI

Bile, Diarrhea,

_

-

Intestine, effect of radiation on.

INTRODUCTION

acid compared to unirradiated controls suggesting that reduced absorption by the ileum had occurred. In related work, Archambeau et al. used dogs prepared with a gallbladder-colon fistula to demonstrate that the presence of bile in sufficient concentrations in the colon induced diarrhea in the dogs2 More recently, Stryker, et al” used the 14C cholylglycine breath test to assess ileal function in patients during pelvic irradiation and demonstrated an increase in 14C02 breath excretion in the fifth week of radiotherapy when most of the patients were experiencing diarrhea suggesting that bile acid malabsorption had occurred with resultant bacterial deconjugation of unabsorbed bile acids in the colon. These investigations support the concept that radiation-induced diarrhea results from a cholerrheic enteropathy as a result of ileal dysfunction with resulting malabsorption of bile salts which, in turn, induce water and electrolyte secretion in the colon.‘2 We have further evaluated this possible mechanism in patients undergoing pelvic irradiation by measuring serum levels of immunoreactive glycine conjugated bile acids prior to and in the fifth week of radiotherapy when patients usually experience gastrointestinal symptoms.

a side effect of pelvic irradiation for pelvic malignancies. The pathophysiologic mechanisms associated with the onset of diarrhea in these patients have not been worked out. Radiationinduced diarrhea is thought to result from the effect of abdominal irradiation on the small intestine which is usually included in the treatment portals.” Previous investigations suggest that a number of factors may be involved in the pathophysiology of radiationinduced diarrhea. Jackson and Entemann found that survival time in rats was increased and gastrointestinal electrolyte losses decreased following whole body irradiation if the bile duct was ligated prior to irradiation.14 Sullivan demonstrated in rats that diversion of bile from the intestine via bile duct-cannulation prior to abdominal irradiation prevented radiation-induced diarrhea.” However, diarrhea occurred in the irradiated rats if bile was injected into the duodenum in quantities comparable to the daily output of bile. In a later study, Sullivan’* showed that within 5 days after irradiation, measurement of radioactivity in the bile of bile duct-cannulated rats was reduced by 70% following injection into the ileum of 14C-labeled bile Diarrhea

Reprint Radiation

is

requests Oncology,

to: J. A. Stryker, M.S. Hershey

Medical

PA 17033, U.S.A. Accepted for publication

M.D., Division of Center, Hershey, 935

13 February

1979.

Radiation

936

Oncology

0 Biology 0 Physics

Table

Patient

Age

Primary

site

I. Patient

Stage’

1.

58

Endometrium

IIG2

2. 3. 4.

77 72 66

Cervix Endometrium Cervix

IIIB IAG2 IIA

5.

46

Endometrium

IIGl

6. 7. 8.

54 63 61

Cervix Endometrium Cervix

IIA 163 IB

9. 10. 11.

42 41 67

Cervix Cervix Endometrium

IIIA IIIA IBGl

12.

56

Cervix

Recurrent

13.

76

14. 15. 16. 17.

55 57 56 70

Cervix Endometrium Endometrium Ovary Endometrium

IVA (bladder) IAG2 IIG 1 IIA IIG3

tTota1 abdominal METHODS

hysterectomy

Chemical

AND MATERIALS

Company,

information

Surgical

history

Time of surgery prior to radiation therapy

Bowel surgery for diverticular disease None TAH & BSOt Pelvic & paraaortic node Bx.

6 years

Resection of ca. cecum None

4 years

TAH & BSO+ Pelvic & paraaortic node Bx. None None Appendicitis & peritonitis Radical hysterectomy & pelvic node dissection None TAH & BSOl None TAH & BSOt None

IO week5 2 weeks

3 weeks 2 weeks

37 years 7/12 months

9 weeks 12 weeks

and bilateral salpingo-oophorectomy

Seventeen patients were selected who were to undergo pelvic irradiation for a gynecological malignancy (Table 1). None of the patients had evidence of disease of the small bowel or liver,6 but one (patient no. 6) had a cholecystectomy 2 years previously.’ Ten of the patients had previous pelvic surgery; 4 of these were to receive post-operative pelvic irradiation for endometrial cancer. Three of the patients were to receive pre-operative pelvic irradiation prior to total abdominal hysterectomy (TAH) and bilateral salpingo-oophorectomy (BSO) for endometrial cancer. One patient (no. 3) was found to have idiopathic thrombocytopenic purpura in the third week of pelvic irradiation and was placed on prednisone. The patients were treated by standard radiotherapy techwere given pelvic irradiation with niques.8 Thirteen anterior and posterior portals and in 3 anterior, posterior and lateral portals were used (box). Fifteen patients were given 850 rad per week in 5 fractions for 5-6 weeks. One was given 900 rad per week. The patient with ovarian cancer was treated by the moving strip technique (2800rad/strip) and a pelvic boost (2000 rad). All of the patients were treated on a linear accelerator with 10 MV X-rays. tMaybridge England

July 1079, Volume 5, No. 7

Tintagel,

Cornwall,

All of the patients came in fasting on the day of their initial radiation treatment. Ten cc of venous blood were drawn for fasting serum cholylglycine (GC) and chenodeoxycholylglycine (GCDC) determinations. The patients were then given a breakfast consisting of 2 scrambled eggs, toast, orange juice and coffee. Two hours following breakfast 1Occ of venous blood were drawn for 2 hr post prandial (2”pp) GC and GCDC determinations. The fasting and 2”pp GC and GCDC determinations were repeated during the fifth week of the patient’s radiation treatments. Radioimmunoassay of bile acids in serum Following blood collection the serum was obtained until it was analyzed. The and stored at -70°C radioimmunoassay procedures for the primary glytine-conjugated bile acids: cholylglycine (GC) and chenodeoxycholylglycine (GCDC) have been described previously.’ Standards of GC and GCDCt purified by thin-layer silicic acid chromatography and patient serum samples were incubated in the presence of specific bile acid antiserum and tritium labeled bile acids.+ Following equilibrium, bile acid-free normal rabbit serum was added and the antibody-bound and free bile acids were separated with polyethylene gly$New England Nuclear, Worcester,

Mass.

Radiation-induced

diarrhea

0 J. A. STRYKER and

questionnaire

The patients were questioned at least once weekly regarding the symptoms of nausea, vomiting and diarrhea and were asked for the number and consistency of their stools for the previous day.

Statistical

analysis

Means and standard deviations were determined by standard methods.22 The paired t-test was used to compare pre-treatment and fifth week serum bile acid determinations. It was also used to compare the first week and fifth week stool frequencies. The unpaired t-test was used to compare the serum bile acid data from the patients who had previous pelvic surgery with the data from the patients who did not have previous surgery. The correlation coefficient was used to correlate serum bile acid levels with the patients’ stool frequencies in the fifth week of radiotherapy. The significance of all tests was based on two-tailed probabilities. RESULTS The results of the fasting and 2”pp serum GC determinations appear in Fig. 1. The pretreatment fasting and 2”pp GC levels were 0.202 0.29 (mean+SD) PM and 0.48 2 0.47 PM respectively. The mean difference between the pretreatment fasting and 2”pp GC levels was 0.28 FM, t = 4.00, DF = 16, P = 0.001. In the fifth week of radiotherapy the fasting and 2”pp GC levels were 0.16 ? 0.23 PM and 0.25 ? 0.27 PM. The mean difference between the fifth week fasting and 2”pp determinations was 0.09 PM, t = 3.75, DF = 16, P (0.01. The pretreatment post prandial rise in serum GC (AGC,) was 0.28 kO.30 PM; in the fifth week of treatment the post prandial rise in serum GC(AGQ was only 0.09? 0.10 PM. The mean difference between AGC, and AGC2 was - 0.19 PM, t = 2.71, DF = 16, P O.l. The 10 patients who had previous pelvic surgery were compared with the 7 who did not have previous surgery. For the pelvic surgery group AGC, was

Radiation

938

Oncology

r&ENODEOXYCHOLYLGLYCiNE 3.4 --

0

Biology

0

Physics

(GCDC)

3.2 3.02.82.62.42.22.01.81.61.41.2l.O.8.6.4.2 F

2”PP

PRETREATMENT

F

2”PP

5th week of Treatment

Fig. 2. Fasting (F) and 2 hr post prandial (pp) serum chenodeoxycholylglycine (GCDC) determinations performed on 17 patients prior to and in the fifth week of pelvic irradiation. 0.30 ? 0.33 PM and AGCZ was 0.10 ? 0.12 PM. For the patients who did not have pelvic surgery AGC’ was 0.26 ? 0.27 PM and AGCZ was 0.08 5 0.07 PM. The mean difference between AGC’ and AGC? in the surgery group was - 0.20 PM and the mean difference between AGC’ and AGCz in the no surgery group was - 0.19 PM. The difference between the means of the 2 groups was only 0.01 PM, t = 0.07, DF = 15, P > 0.5. DISCUSSION Our $ata suggest that pelvic irradiation induces bile acid malabsorption since the post prandial rise in serum GC and GCDC levels was not as great in the fifth week of treatment as it was prior to treatment. Bile acids are formed in the liver from cholesterol, stored and concentrated in the gallbladder and secreted into the intestine after the ingestion of a meal.4 After facilitating the absorption of dietary lipids, bile acids are absorbed by the small intestine and carried in portal blood to the liver where uptake and resecretion occurs. Efficient hepatic clearance from portal blood maintains serum bile acid concentrations at low levels. In normal subjects serum bile acid concentrations increase after meals and peak at 90-120 min; they return to baseline levels within 4 hr.“,” Since bile acids are normally reabsorbed most

July

1979,

Volume

5, No. 7

efficiently in the terminal ileum, a reduction in the peak serum GC and GCDC concentrations at 2 hr following a meal (as occurred in our patients) suggests that abnormal absorptive function by the terminal ileum has occurred. We conclude, therefore, that abnormal bile acid transport occurred in our patients because of ileal dysfunction. Diarrhea occurs in patients who have ileal dysfunction because conjugated bile salts pass into the colon where they induce secretion of free water by the colon. Our patients experienced a significant increase in stool frequency during their treatment course but the severity of the diarrhea could not be correlated with the degree of ileal dysfunction. The reason for the lack of correlation may have been the result of differences in the colon’s ability to reabsorb water between patient? and also because other factors may be involved in the severity of diarrhea in addition to bile acid malabsorption.2’ The diarrhea experienced by most of our patients was not marked, suggesting that the ileal dysfunction was not severe; it is possible that better correlation would have been observed had the physiologic alterations been greater. However, our data suggest that the bile acid pool may become somewhat reduced following pelvic irradiation because of fecal losses since the fasting GC and GCDC in the fifth week of treatment were somewhat lower than pretreatment levels althe differences were though not statistically significant. There was no evidence that bile acid metabolism was different in our patients who had undergone previous pelvic surgery from those who had not undergone pelvic surgery. This observation was somewhat unexpected but it is possible that the surgical procedures performed on our patients did not result in significant pelvic fixation of small intestine. The results of our investigation support the use of cholestyramine in the management of patients having radiation-induced diarrhea. Cholestyramine is a nonabsorbable ion exchange resin that binds bile salts before they pass into the colon to induce water and electrolyte secretion with resulting watery diarrhea. This drug has been used in the treatment of cholerrheic enteropathy following ileal resectionI and, in rats, Burke and Seay3 were able to reduce mortality from abdominal irradiation by pretreatment with cholestyramine. More recently, Heusinkveld et al” used cholestyramine to successfully treat 7 patients with acute or chronic radiation-induced diarrhea that was refractory to routine methods of control. In conclusion we believe that our data tend to support the concept that one of the causes of radiation-induced diarrhea is a cholerrheic enteropathy. Further studies are needed to evaluate the possible role of cholestyramine in the prophylaxis and treatment of radiation-induced diarrhea.

Radiation-induced diarrhea 0

J. A. STRYKER and

L. M. DEMERS

939

REFERENCES 1. American joint committee for cancer staging and endresults reporting (AJCCS): In Manual for Staging of Cancer, Chicago, AJCCS. 1977, pp 89-100. 2. Archambeau, J.O., Maetz, M., Jesseph, J.E., Brenneis, H.J.: Production of diarrhea in dogs prepared with a gallbladder-colon fistula. Arch Surg. 95: 230-235, 1967. 3. Berk, R.N., Seay, D.G.: Cholerheic enteropathy as a cause of diarrhea and death in radiation enteritis and its prevention with cholestyramine. Radiology 104: 153156, 1972. 4. Davenport, H.W.: Secretion of the bile, In Physiology of the Digestive Tract, 3rd Edn, Chicago, Illinois, Year Book Medical Publishers, Inc., 1971, Chap. 10, pp 129138. 5. Davenport, H.W.: Absorption and excretion by the colon, In Physiology of the Digestive Tract, 3rd Edn, Chicago, Illinois, Year Book Medical Publishers, Inc., 1971, Chap. 18, pp 211-217. 6. Demers, L.M., Hepner, G.W.: Levels of immunoreactive glycine-conjugated bile acids in health and hepatobiliary disease. Am. J. Clin. Path. I%: 831-839, 1976. 7. Demers, L.M., Hepner, G.W.: Radioimmunoassay of bile acids in serum. Clin. Chem. 22: 602-606, 1976. 8. Fletcher, G.H.: Female pelvis, In Textbook of Radiotherapy, Philadelphia, Lea & Febiger, 1966, Chap. 10, pp 434-474. 9. Hepner, G.W.: Effect of decreased gallbladder stimulation on enterohepatic cycling and kinetics of bile acids. Gastroenterology 68: 1574-1581, 1975. 10. Hepner, G.W., Demers, L.M.: The dynamics of the enterohepatic circulation of the glycine conjugates of cholic, chenodeoxycholic, deoxycholic and sulfolithocholic acid in man. Gastroenterology 72: 499-501, 1977. 11. Heusinkveld, R.S., Manning, M.R., Aristizabal, S.A.:

Control ramine.

of radiation-induced Int. J. Radiat.

diarrhea

with cholesty-

Oncol. Biol. Phys. 4: 687-690,

1978. 12. Hofmann,

13.

14.

15. 16.

17.

18. 19.

20.

A.F.: The syndrome of ileal disease and the broken enterohepatic circulation: Cholerrheic enteropathy. Gastroenterology 52: 752-757, 1976. Hofmann, A.F., Poley, J.R.: Cholestyramine treatment of diarrhea associated with ileal resection. N. Engl. J. Med. 281: 397-402, 1969. Jackson, K.L., Entenman, C.: The role of bile secretion in the gastrointestinal radiation syndrome. Radiat. Res. 10: 67-79, 1959. LaRusso, N.F., Korman, M.G., Hoffman, N.E., Hofmann, A.F.: Dynamics of the enterohepatic circulation of bile acids. N. Engl. J. Med. 291: 689-692, 1974. Robard, D.: Statistical quality control and routine data processing for radioimmunoassays and immunoradiometric assays. Clin. Chem. 20; 1255-1264, 1974. Clinical Radiation Rubin, P., Casarett, G.W.: Pathology. Philadelphia, WB Saunders, 1968, pp 193240. Sullivan, M.F.: Bile salt absorption in the irradiated rat. Am. J. Physiol. 209(l): 158-164, 1965. Sullivan, M.F.: Dependence of radiation diarrhea on the presence of bile in the intestine. Nature 195: 1217-1218, 1962. Stryker, J.A., Hepner, G.W., Mortel, R.: The effect of pelvic irradiation on ileal function. Radiology 124: 213-

216, 1977. 21. Stryker, J.A., Mortel, R., Hepner,

pelvic irradiation

G.W.: The effect of on lactose absorption. Int. J. Radiat.

Oncol. Biol. Phys. 4: 859-863, 1978. 22. Swinscow, T.D.V.: Statistics at Square

Br. Med. Assoc., 1978.

One. London,