1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
IJSU1930_proof ■ 10 June 2015 ■ 1/6
International Journal of Surgery xxx (2015) 1e6
Contents lists available at ScienceDirect
International Journal of Surgery journal homepage: www.journal-surgery.net
Original research
Q4 Q3
The current role of intraoperative ultrasound during the resection of colorectal liver metastases: A retrospective cohort study Sarah A. Knowles a, *, Kimberly Bertens a, Kristopher P. Croome b, Roberto Hernandez-Alejandro a a b
Western University, Division of General Surgery, 339 Windermere Rd, PO Box 5339, London, ON N6A 5A5, Canada Mayo Clinic, Division of Gastroenterologic and General Surgery, 15, 1st Street SE 501, Rochester, MN 55904, USA
h i g h l i g h t s Q1
A retrospective cohort study examining the role of intraoperative ultrasound (IOUS) during the resection colorectal liver metastases (CRLM). IOUS provides novel information about the lesions that can lead to a change in the operative plan, ensuring complete resection. There is a trend toward improved disease free survival in the IOUS group. Despite improvement in preoperative imaging, IOUS still plays an important role during hepatic resections for CRLM.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 13 October 2014 Received in revised form 6 March 2015 Accepted 29 May 2015 Available online xxx
Introduction: Liver resections with negative margins improve survival in patients with colorectal liver metastases (CRLM). Intraoperative ultrasound (IOUS) is a valuable tool that gives information about lesions that ultimately changes surgical strategy to ensure complete removal, which subsequently improves disease free survival (DFS). Methods: A retrospective review of patients who underwent a resection for CRLM from 2009 to 2012 was completed to determine the impact of IOUS. Results: A total of 103 patients had a hepatic resection for CRLM. All patients had a preoperative imaging to assist with operative planning. IOUS was performed in 72 cases. Surgical strategy changed in 31 (43.1%) cases with IOUS, compared to three (9.7%) with no IOUS (P < 0.001). A new lesion was detected in 13 (18.1%) of the cases. A higher proportion of nonanatomic liver resections were performed in the IOUS group (N ¼ 27, 37.5%) compared to the non-IOUS group (N ¼ 6, 19.4%) (P ¼ 0.07). Conclusion: Achievement of a negative resection margin was comparable between the two groups. However, there was a trend toward improved DFS in the IOUS group. Despite advances in preoperative imaging, IOUS demonstrates utility in providing novel information that allows removal of the entire tumor burden, using parenchymal-preserving techniques when feasible, leading to improved DFS. © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.
Keywords: Colorectal cancer Liver/hepatic metastases Intraoperative ultrasound
1. Introduction Colorectal cancer is the third most commonly diagnosed cancer and is the second leading cause of cancer-related death in the United States [1]. Metastatic disease is the cause of death in over half of these patients. The most common site of metastases is the liver. Approximately 15e30% of patients will present with synchronous metastases, while another 20% will develop
* Corresponding author. E-mail address: [email protected] (S.A. Knowles).
metachronous disease by 5 years. It is estimated that 35e55% of patients will develop liver metastases at some point during the course of their disease [2,3]. Currently, resection of the liver metastases plus or minus the addition of chemotherapy is the only option for curative intent. Liver resections with negative margins improve survival in patients with colorectal liver metastases (CRLM). In a recent study, 5-year survival was up to 55% when R0 resection was achieved, compared to less than 26% with positive margins [4]. Intraoperative ultrasound is a valuable tool during liver surgery for CRLM. Despite advances in preoperative imaging, IOUS still provides important information at the time of surgery. Several
http://dx.doi.org/10.1016/j.ijsu.2015.05.052 1743-9191/© 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: S.A. Knowles, et al., The current role of intraoperative ultrasound during the resection of colorectal liver metastases: A retrospective cohort study, International Journal of Surgery (2015), http://dx.doi.org/10.1016/j.ijsu.2015.05.052
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
IJSU1930_proof ■ 10 June 2015 ■ 2/6
2
S.A. Knowles et al. / International Journal of Surgery xxx (2015) 1e6
small studies suggest that IOUS can help detect additional lesions not seen on preoperative imaging or have developed in the interim between imaging and surgery. This subsequently changes the surgical strategy to either a more extensive or conservative resection. Detection rates for additional lesions vary from 10 to 20% and changes in surgical strategy occurred in up to 30% of the studies [5e9]. There is however, a lack of evidence on the impact of IOUS on both intraoperative blood loss and the achievement of negative resection margins. Many studies have shown that excessive blood loss is an independent predictor for major postoperative complications following a hepatic resection [10,11]. Using IOUS during hepatic resection helps to visualize the tumor in relation to adjacent vascular structures in order to incorporate or exclude them during resection and potentially minimize blood loss. Additionally, intraoperative visualization of the tumor using ultrasound imaging conveys a greater ability to achieve negative resection margins by offering dynamic feedback to the surgeon. The purpose of this study is to determine the benefit of IOUS during the resection of CRLM. Specifically, we aim to demonstrate the role of IOUS in 1) detecting new lesions and verifying lesions compared to preoperative imaging, 2) guiding surgical decisionmaking which could potentially lead to a change in the operative plan, 3) ensuring a complete resection which subsequently improves disease free survival and 4) minimizing blood loss. 2. Materials and methods This study was reported according to the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) checklist for cohort studies, found at http://www.strobe-statement. org/ [12]. 2.1. Patient population This is a retrospective cohort study of patients who underwent a liver resection for CRLM at London Health Sciences Centre (LHSC) from March 2009 to December 2012. Cases were identified using a database compiled by the HPB Fellow of all hepatic resections performed at this institution. Only cases where a hepatic resection was performed for CRLM who had preoperative imaging were included. All patients were at least 18 years old. Patients were divided into two groups depending on if they had an IOUS performed or not. 2.2. Preoperative imaging and operative planning Patients either had contrast-enhanced triphasic computed tomography (CT) imaging or magnetic resonance (MR) imaging preoperatively. Both the staff surgeons and radiologists reviewed all imaging prior to surgery in order to determine the location and number of metastases and to plan the operative approach. Patients were also discussed at interdisciplinary tumor board rounds. 2.3. Intraoperative ultrasound The surgeons at LHSC are experienced in performing and interpreting the findings of IOUS with the assistance of a qualified ultrasound technician present in the operating room. Radiologists are available for consultation if needed. There are a select few HPB surgeons who do not perform IOUS regularly as part of their practice, which makes up the cohort of patients who did not have IOUS.
2.4. Types of resections The type of resection was also recorded. Anatomic resections were subdivided into major and minor. Major anatomic resections were defined as three or more liver segments as defined by Couinaud [13,14]. Minor anatomic resections were defined as one to two anatomic hepatic segments. Nonanatomic resections were defined as any wedge or partial resection of one or multiple segments. 2.5. Change in surgical strategy A change in surgical strategy was defined as any change in the actual procedure from the planned procedure. The planned procedure was ascertained from the preoperative clinic notes. It was then determined whether or not the IOUS findings were responsible for the change based on the operative note. The reason for change in surgical strategy was also recorded: new or more lesion(s), disappearing lesion(s), appearance of the lesion(s) as benign, location of the lesion(s) and size of the lesion(s). 2.6. Blood loss Blood loss is a difficult and often subjective variable to measure. The most objective approach to estimate bloods loss was to use a validated formula as described by Wu et al. for major surgical procedures: BL ¼ (31.265 preop HCT) (29.83 postop HCT) þ (269.67 units PRBCs), where HCT ¼ hematocrit and PRBs ¼ packed red blood cells [15,16]. 2.7. Patient follow up All patients were seen in follow up at one month from surgery then every three months for the first year by the surgical team. There were then seen annually in follow up by the surgical team. Some patients would have been seen more frequently if there were any postoperative issues, such as a wound infection. They were also followed by an interdisciplinary team that included medical oncologists. 2.8. Statistical analysis All statistics were computed using IBM SPSS Statistics (Version 21). Analysis of variance (ANOVA) was used for the continuous variables such as time to preoperative imaging and blood loss. Chisquare or Fisher exact tests were used for the categorical variables such as achievement of negative resection margins and change in the operative plan. A KaplaneMeier survival analysis was performed for disease free survival. A P value of
IJSU1930_proof ■ 10 June 2015 ■ 1/6
International Journal of Surgery xxx (2015) 1e6
Contents lists available at ScienceDirect
International Journal of Surgery journal homepage: www.journal-surgery.net
Original research
Q4 Q3
The current role of intraoperative ultrasound during the resection of colorectal liver metastases: A retrospective cohort study Sarah A. Knowles a, *, Kimberly Bertens a, Kristopher P. Croome b, Roberto Hernandez-Alejandro a a b
Western University, Division of General Surgery, 339 Windermere Rd, PO Box 5339, London, ON N6A 5A5, Canada Mayo Clinic, Division of Gastroenterologic and General Surgery, 15, 1st Street SE 501, Rochester, MN 55904, USA
h i g h l i g h t s Q1
A retrospective cohort study examining the role of intraoperative ultrasound (IOUS) during the resection colorectal liver metastases (CRLM). IOUS provides novel information about the lesions that can lead to a change in the operative plan, ensuring complete resection. There is a trend toward improved disease free survival in the IOUS group. Despite improvement in preoperative imaging, IOUS still plays an important role during hepatic resections for CRLM.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 13 October 2014 Received in revised form 6 March 2015 Accepted 29 May 2015 Available online xxx
Introduction: Liver resections with negative margins improve survival in patients with colorectal liver metastases (CRLM). Intraoperative ultrasound (IOUS) is a valuable tool that gives information about lesions that ultimately changes surgical strategy to ensure complete removal, which subsequently improves disease free survival (DFS). Methods: A retrospective review of patients who underwent a resection for CRLM from 2009 to 2012 was completed to determine the impact of IOUS. Results: A total of 103 patients had a hepatic resection for CRLM. All patients had a preoperative imaging to assist with operative planning. IOUS was performed in 72 cases. Surgical strategy changed in 31 (43.1%) cases with IOUS, compared to three (9.7%) with no IOUS (P < 0.001). A new lesion was detected in 13 (18.1%) of the cases. A higher proportion of nonanatomic liver resections were performed in the IOUS group (N ¼ 27, 37.5%) compared to the non-IOUS group (N ¼ 6, 19.4%) (P ¼ 0.07). Conclusion: Achievement of a negative resection margin was comparable between the two groups. However, there was a trend toward improved DFS in the IOUS group. Despite advances in preoperative imaging, IOUS demonstrates utility in providing novel information that allows removal of the entire tumor burden, using parenchymal-preserving techniques when feasible, leading to improved DFS. © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.
Keywords: Colorectal cancer Liver/hepatic metastases Intraoperative ultrasound
1. Introduction Colorectal cancer is the third most commonly diagnosed cancer and is the second leading cause of cancer-related death in the United States [1]. Metastatic disease is the cause of death in over half of these patients. The most common site of metastases is the liver. Approximately 15e30% of patients will present with synchronous metastases, while another 20% will develop
* Corresponding author. E-mail address: [email protected] (S.A. Knowles).
metachronous disease by 5 years. It is estimated that 35e55% of patients will develop liver metastases at some point during the course of their disease [2,3]. Currently, resection of the liver metastases plus or minus the addition of chemotherapy is the only option for curative intent. Liver resections with negative margins improve survival in patients with colorectal liver metastases (CRLM). In a recent study, 5-year survival was up to 55% when R0 resection was achieved, compared to less than 26% with positive margins [4]. Intraoperative ultrasound is a valuable tool during liver surgery for CRLM. Despite advances in preoperative imaging, IOUS still provides important information at the time of surgery. Several
http://dx.doi.org/10.1016/j.ijsu.2015.05.052 1743-9191/© 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: S.A. Knowles, et al., The current role of intraoperative ultrasound during the resection of colorectal liver metastases: A retrospective cohort study, International Journal of Surgery (2015), http://dx.doi.org/10.1016/j.ijsu.2015.05.052
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
IJSU1930_proof ■ 10 June 2015 ■ 2/6
2
S.A. Knowles et al. / International Journal of Surgery xxx (2015) 1e6
small studies suggest that IOUS can help detect additional lesions not seen on preoperative imaging or have developed in the interim between imaging and surgery. This subsequently changes the surgical strategy to either a more extensive or conservative resection. Detection rates for additional lesions vary from 10 to 20% and changes in surgical strategy occurred in up to 30% of the studies [5e9]. There is however, a lack of evidence on the impact of IOUS on both intraoperative blood loss and the achievement of negative resection margins. Many studies have shown that excessive blood loss is an independent predictor for major postoperative complications following a hepatic resection [10,11]. Using IOUS during hepatic resection helps to visualize the tumor in relation to adjacent vascular structures in order to incorporate or exclude them during resection and potentially minimize blood loss. Additionally, intraoperative visualization of the tumor using ultrasound imaging conveys a greater ability to achieve negative resection margins by offering dynamic feedback to the surgeon. The purpose of this study is to determine the benefit of IOUS during the resection of CRLM. Specifically, we aim to demonstrate the role of IOUS in 1) detecting new lesions and verifying lesions compared to preoperative imaging, 2) guiding surgical decisionmaking which could potentially lead to a change in the operative plan, 3) ensuring a complete resection which subsequently improves disease free survival and 4) minimizing blood loss. 2. Materials and methods This study was reported according to the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) checklist for cohort studies, found at http://www.strobe-statement. org/ [12]. 2.1. Patient population This is a retrospective cohort study of patients who underwent a liver resection for CRLM at London Health Sciences Centre (LHSC) from March 2009 to December 2012. Cases were identified using a database compiled by the HPB Fellow of all hepatic resections performed at this institution. Only cases where a hepatic resection was performed for CRLM who had preoperative imaging were included. All patients were at least 18 years old. Patients were divided into two groups depending on if they had an IOUS performed or not. 2.2. Preoperative imaging and operative planning Patients either had contrast-enhanced triphasic computed tomography (CT) imaging or magnetic resonance (MR) imaging preoperatively. Both the staff surgeons and radiologists reviewed all imaging prior to surgery in order to determine the location and number of metastases and to plan the operative approach. Patients were also discussed at interdisciplinary tumor board rounds. 2.3. Intraoperative ultrasound The surgeons at LHSC are experienced in performing and interpreting the findings of IOUS with the assistance of a qualified ultrasound technician present in the operating room. Radiologists are available for consultation if needed. There are a select few HPB surgeons who do not perform IOUS regularly as part of their practice, which makes up the cohort of patients who did not have IOUS.
2.4. Types of resections The type of resection was also recorded. Anatomic resections were subdivided into major and minor. Major anatomic resections were defined as three or more liver segments as defined by Couinaud [13,14]. Minor anatomic resections were defined as one to two anatomic hepatic segments. Nonanatomic resections were defined as any wedge or partial resection of one or multiple segments. 2.5. Change in surgical strategy A change in surgical strategy was defined as any change in the actual procedure from the planned procedure. The planned procedure was ascertained from the preoperative clinic notes. It was then determined whether or not the IOUS findings were responsible for the change based on the operative note. The reason for change in surgical strategy was also recorded: new or more lesion(s), disappearing lesion(s), appearance of the lesion(s) as benign, location of the lesion(s) and size of the lesion(s). 2.6. Blood loss Blood loss is a difficult and often subjective variable to measure. The most objective approach to estimate bloods loss was to use a validated formula as described by Wu et al. for major surgical procedures: BL ¼ (31.265 preop HCT) (29.83 postop HCT) þ (269.67 units PRBCs), where HCT ¼ hematocrit and PRBs ¼ packed red blood cells [15,16]. 2.7. Patient follow up All patients were seen in follow up at one month from surgery then every three months for the first year by the surgical team. There were then seen annually in follow up by the surgical team. Some patients would have been seen more frequently if there were any postoperative issues, such as a wound infection. They were also followed by an interdisciplinary team that included medical oncologists. 2.8. Statistical analysis All statistics were computed using IBM SPSS Statistics (Version 21). Analysis of variance (ANOVA) was used for the continuous variables such as time to preoperative imaging and blood loss. Chisquare or Fisher exact tests were used for the categorical variables such as achievement of negative resection margins and change in the operative plan. A KaplaneMeier survival analysis was performed for disease free survival. A P value of
