University of Groningen. Colorectal Anastomoses Bakker, Ilsalien

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1 University of Groningen Colorectal Anastomoses Bakker, Ilsalien IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2016 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Bakker, I. (2016). Colorectal Anastomoses: Surgical outcome and prevention of anastomotic leakage [Groningen]: Rijksuniversiteit Groningen Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date:

2 Chapter HIGH MORTALITY RATES AFTER NON-ELECTIVE COLON CANCER RESECTION: RESULTS OF A NATIONAL AUDIT I.S. BAKKER H.S. SNIJDERS I. GROSSMANN T.M. KARSTEN K. HAVENGA T. WIGGERS COLORECTAL DISEASE JAN 8

3 Chapter ABSTRACT BACKGROUND: Colon cancer resection in a non-elective setting is associated with high rates of morbidity and mortality. The aim of this retrospective study is to identify risk factors for overall mortality after colon cancer resection with a special focus on non-elective resections. METHOD: Data were obtained from the Dutch Surgical Colorectal Audit. Patients undergoing colon cancer resection in the Netherlands between January 2009 and December 201 were included. Patient, treatment and tumour factors were analyzed in relation to the urgency of surgery. The outcome was thirty days postoperative mortality. RESULTS: The study included patients. In 19.2% of patients, non-elective colon cancer resection was performed. There was a 4.4% overall mortality rate, with significantly more deaths after non-elective surgery (8.5% vs.4%, P<0.001). Patients with older age, male gender, high comorbidity, advanced tumours, perforated tumours, a tumour in the right or transverse colon and postoperative anastomotic leakage were at risk for postoperative death. In non-elective resections, a right-sided tumour and postoperative anastomotic leakage were associated with high mortality. CONCLUSION: Non-elective colon cancer resection is associated with high mortality. In particular, right-sided resections and patients with a tumour perforation have a high mortality risk. The optimization of patients prior to surgery and operation in an early timeframe after diagnosis might prevent non-elective resections. 42

4 Mortality rates after non-elective colon cancer resection INTRODUCTION Up to thirty percent of patients with colon cancer present with acute symptoms, such as obstruction, perforation or severe bleeding (1-), requiring non-elective surgery (1,2,4). Colon resections in this setting are associated with increased postoperative morbidity, higher anastomotic leakage rates and increased mortality (4-7). Therefore, non-elective surgical management in colon cancer is a challenging clinical problem and should be avoided whenever possible. Optimization of patients prior to surgical resection by creating a defunctioning stoma, placement of a stent for obstructed tumours (8,9) or transfusion for bleeding tumours may result in a better outcome. However, strategies to avoid non-elective surgical resection in perforated colon tumours are lacking (6). In addition to the non-elective setting of surgery, several other risk factors including high age, high American Society of Anesthesiologists classification, stage of disease and intraoperative complications are associated with an increased complication rate, more anastomotic leakage and a higher mortality rate (2,10,11). The type of colon resection seems to be of influence on the outcome. Several studies have shown higher anastomotic leakage rates after left-sided colon resections (12-14), whereas right-sided colectomy and transverse resections seem to be associated with higher mortality rates (2,15). The Dutch Surgical Colorectal Audit (DSCA) is a quality institution in which all Dutch hospitals participate. This audit was initiated in 2009 to monitor and improve surgical outcome for patients with colorectal cancer. The DSCA facilitates individual hospitals in quality improvement projects and is also used to identify treatment and outcome patterns for different patient groups. The DSCA includes information on all operated colorectal cancer patients in the Netherlands, both elective and non-elective. The aim of this study is to use these population-based data from the DSCA to analyze patient, tumour and treatment characteristics as risk factors for overall mortality, with a special focus on non-elective resections. MATERIALS AND METHODS STUDY POPULATION Data were obtained from the DSCA, a prospectively registered database, concerning information on patient factors, comorbidity, disease specific information, diagnostics, treatments and 4

5 Chapter outcome, with a nearly 100% concordance on validation against the National Cancer Registry (16,17). The dataset of the DSCA includes data from 92 hospitals. In the founding year of 2009, 89% of all Dutch hospitals participated, which increased to 100% of all hospitals performing colorectal surgery. All patient information in the DSCA is collected anonymously; therefore, no approval from the medical ethics committee was required for the present study. All patients undergoing colon cancer resection between the 1st of January 2009 and the 1st of December 201 were included in the evaluation. Minimal data requirements for inclusion in analyses were information on the date of surgery, type of surgery, the occurrence of anastomotic leakage and mortality. OUTCOME Potential risk factors for mortality were extracted from the DSCA. We analyzed patient factors (age, gender, body mass index, Charlson s comorbidity score and American Society of Anesthesiologists classification), tumour factors (tumour complications and tumour stage and location) as well as treatment factors (urgency of surgery, anastomosis and/or stoma creation and extensive tumour resections, which were defined as all additional resections performed due to invasive tumours). Tumour location was divided into right-sided (tumour located in the ascending colon or hepatic flexure), transverse (tumour located in the transverse colon, including the splenic flexure) and left sided (tumour located in the descending colon or sigmoid) tumours. Tumour complications were classified into tumour perforation defined as preoperative tumour perforation with clinical signs of fecal peritonitis; obstruction defined as preoperative presence of (partial) mechanical bowel obstruction with symptoms of abdominal cramping, abdominal distention, nausea, vomiting or failure to pass gas or stool; and bleeding, defined as preoperative tumour related blood loss requiring intervention (transfusion or urgent operation) or leading to anemia (Hb <7 mmol in male patients and <6.5 mmol/l in female patients). Non-elective surgery was defined as a surgical intervention required within twenty-four hours after unplanned admission. Anastomotic leakage was defined as clinically relevant leakage requiring surgical or radiological re-intervention. Mortality was defined as both in-hospital mortality and mortality within 0 days after primary surgery. STATISTICAL ANALYSIS Patient, tumour and treatment characteristics were described in relation to the urgency of surgery (elective or non-elective surgery). Univariate analyses were performed to identify possible risk 44

6 Mortality rates after non-elective colon cancer resection factors for overall mortality. Logistic multivariate analysis was performed to adjust for possible confounders with the inclusion of all possible risk factors with a significance level of P<0.05 in univariate analysis. A second multivariate analysis was performed for the elective and nonelective groups. The results were reported in odds ratios and 95% confidence intervals. Analyses were considered to be statistically significant with a p-value <0.05. All data were analyzed using PASW Statistics, Release (SPSS Inc, Chicago, IL). RESULTS Between January 2009 and December 201, a total amount of 46.2 patients with primary colorectal carcinoma undergoing colorectal resection were registered in the database of the DSCA. From these patients underwent rectal cancer resection and patients had a double tumour. After exclusion of these patients, data from patients undergoing colon cancer resection were included in the database of the DSCA. Patient characteristics are shown in Table 1. From all patients undergoing colon cancer resections, (48.2%) patients were female, (80.8%) patients underwent elective surgery and (19.2%) patients were operated in a non-elective setting. From all included patients, 966 (.1%) patients presented with tumour perforation, (14.4%) with obstruction due to the tumour and.985 (12.9%) patients with a bleeding tumour; (69.6%) patients did not have any registered preoperative tumour complications. TABLE 1. PATIENT AND TUMOUR CHARACTERISTICS OF PATIENTS UNDERGOING COLON CANCER SURGERY IN THE NETHERLANDS BETWEEN JANUARY 2009 AND DECEMBER 201 ELECTIVE NON- ELECTIVE N % N % N % Patient factors Age Gender Female ASA classification* I-II III Charlson I II Body mass index < > Tumour factors Tumour Stage ctx ct ct

7 Chapter Tumour Location Left colon Transverse colon Right colon Tumour symptoms None Perforation Obstruction Bleeding Treatment factors Extensive resections Yes No Surgical Procedure Anastomosis Defunctioning stoma End-ileostomy End-colostomy Surgical approach Laparotomy Laparoscopy Results of Chi Squared test. *ASA = American Society of Anesthesiologists RISK FACTORS FOR MORTALITY AFTER COLON CANCER SURGERY Results of univariate analyses of possible risk factors for overall mortality after colon cancer resection are shown in Table 2. There was a 4.4% overall mortality rate, with significantly more deaths after non-elective surgery (8.5% vs.4% in elective setting, p<0.001). Of all patients operated on for colon cancer, 6.4% developed anastomotic leakage. There was a small difference in the leakage rate between elective and non-elective colon resections of 6.2 vs 7.1% (p=0.001), respectively. From the patients with anastomotic leakage, 268 (1.5%) died within 0 days postoperative, compared to a.7% mortality rate in patients without clinical leakage. TABLE 2. UNIVARIATE ANALYSES OF POSSIBLE RISK FACTORS FOR OVERALL MORTALITY OF ALL PATIENTS UNDERGOING COLON CANCER RESECTION, N= OVERALL MORTALITY N % p-value Patient factors Age < < Gender female male ASA classification* I-II <0.001 III Charlson score <0.001 I II Body mass index <

8 Mortality rates after non-elective colon cancer resection > Tumour factors Tumour Stage ctx <0.001 ct ct Preoperative acute symptoms None <0.001 Tumour perforation Obstruction Bleeding Tumour location Right colon <0.001 Transversum Left colon Treatment factors Extensive resections No <0.001 Yes Surgical Procedure Anastomosis <0.001 Defunctioning stoma End-ileostomy End-colostomy Urgency Elective <0.001 Non-elective Anastomotic Leakage No <0.001 Yes Surgical approach Laparotomy <0.001 Laparoscopy *ASA = American Society of Anesthesiologists Mortality rates were highest in elderly patients, as well as patients with a high American Society of Anesthesiologists classification, high Charlson score and a higher tumour stage. Patients with preoperative tumour complications such as perforation and obstruction also had higher mortality, up to 1.% in patients with a tumour perforation. Patients undergoing a transverse resection or right colectomy had higher mortality rates than after left-sided colectomy at 6.8%, 4.7% and.5%, respectively. Additionally, patients with an end-ileostomy or end-colostomy showed high mortality. Body mass index did not influence the overall mortality rate. Patients undergoing laparoscopic resection showed less mortality compared to patients undergoing open resection at 2.5 and 5.8%, respectively. Multivariate analysis showed that older age, male gender, high American Society of Anesthesiologists classification, and high Charlson score were independent risk factors for postoperative mortality (Table ). Additionally, more advanced tumours, preoperative tumour perforation and transverse resection or right-sided colectomy were independent risk factors for mortality. Non-elective resections and open surgical resections were associated with higher 47

9 Chapter mortality rates compared to elective resections. Anastomotic leakage was an independent risk factor for mortality. TABLE. MULTIVARIATE ANALYSES OF POSSIBLE RISK FACTORS FOR OVERALL MORTALITY AFTER COLON CANCER SURGERY, N=0.907 OVERALL MORTALITY OR p-value 95% CI Patient factors Age < < ,201 2,954 Gender Female 1.0 Male 1,1 < ,141 1,502 ASA* I-II 1.0 III+ 2,26 < ,611 Charlson I 1,42 < ,181 1,714 II+ 2,16 < ,825 2,560 Body mass index < , , >0 0,88 0, Tumour factors Tumour Stage ctx ct 2,26 < ,888 2,701 ct4 1, ,950 2,102 Preoperative symptoms None 1.0 Perforation 1, ,250 2,428 Obstruction 1,00 0,989 0,780 1,278 Blood loss 1,05 0,607 0,86 1,288 Tumour location Left colon 1.0 Transversum 1,51 < ,268 1,785 Right colon 2,02 < ,640 2,482 Treatment factors Extensive resections No 1.0 Yes 1, ,096 1,90 Surgical procedure Anastomosis 1.0 Defunctioning stoma 1,6 0,05 0,996 1,857 End-ileostomy 1,86 0,002 1,255 2,760 End-colostomy 1,67 < ,17 2,110 Urgency Elective 1.0 Non elective 1,55 < ,29 1,97 Anastomotic leakage No 1.0 Yes 4,84 < ,074 5,749 Surgical approach Laparoscopy 1.0 Laparotomy 1,4 < ,147 1,56 *ASA = American Society of Anesthesiologists 48

10 Mortality rates after non-elective colon cancer resection Table 4 shows the results of multivariate analysis for risk factors for mortality according to the urgency of surgery. In both the elective and the non-elective groups, patient factors such as older age, higher American Society of Anesthesiologists classification and higher Charlson classification were independent risk factors. A tumour located in the right colon or transversum had higher odds for mortality in both groups, as well as the occurrence of anastomotic leakage. In patients undergoing elective surgery, a higher tumour stage, open surgical resection and extensive resections during surgery were independent risk factors for mortality. Patients in the non-elective surgery group had higher odds for mortality when presenting with a perforated tumour and when an end-ileostomy needed to be constructed during surgery. TABLE 4. MULTIVARIATE ANALYSIS OF RISK FACTORS FOR POSTOPERATIVE MORTALITY IN PATIENTS UNDERGOING ELECTIVE RESECTION (N=24.960) AND AFTER NON-ELECTIVE RESECTION (N=5.947) ELECTIVE SURGERY NON-ELECTIVE SURGERY N= N=5.947 OR p-value 95% CI OR p-value 95% CI Patient factors Age < ,57 < ,112,008 2,70 < ,066,55 Gender Female male 1,41 < ,190 1,655 1, ,880 1,459 ASA* I-II III+ 2,10 < ,757 2,478 2,65 < ,026,45 Charlson I 1, ,162 1,828 1, ,965 1,872 II+ 2,28 < ,857 2,796 1,91 < ,40 2,587 Body mass index < ,404 0,59 1, , ,160 0,461 1,16 > ,49 0, ,72 0,218 0,419 1,219 Tumour factors Tumour Stage ctx ct 2,64 < ,160,217 1,21 0,77 0,792 1,850 ct4 1, ,842 2,7 1,1 0,405 0,696 2,45 Preoperative symptoms None Perforation 1,15 0,7 0,518 2,548 1,87 0,00 1,24 2,82 Obstruction 1,15 0,521 0,757 1,7 0,96 0,829 0,694 1,40 Blood loss 1,10 0,75 0,891 1,58 0,68 0,677 0,426 1,79 Tumour location Left colon Transversum 1,47 < ,206 1,78 1, ,16 2,87 Right colon 1,75 < ,50 2,267 2,61 < ,810,752 Treatment factors Extensive resections No Yes 1, ,988 2,021 1, ,96 2,458 Surgical procedure Anastomosis Defunctioning stoma 1,22 0,78 0,786 1,888 1,51 0,081 0,951 2,8 49

11 Chapter End-ileostomy ,298 0,168 1,725 2,15 0,001 1,61,406 End-colostomy 2,8 < ,775,199 1,14 0,519 0,769 1,68 Anastomotic leakage No Yes 5,45 < ,479 6,68,50 < ,447 5,012 Surgical approach Laparoscopy Laparotomy 1.40 < ,188 1,660 1,10 <0,677 0,72 1,648 *ASA = American Society of Anesthesiologists DISCUSSION The present study on colon cancer resection in the Netherlands shows high mortality rates in patients undergoing non-elective surgery. In particular, patients presenting with tumour perforation, patients undergoing right-sided non-elective colon resection and patients with postoperative anastomotic leakage are all associated with a high mortality risk. In concordance with findings from the literature (1-), almost twenty percent of all colon cancer resections in the Netherlands are performed in a non-elective setting. The present results show an anastomotic leakage rate of 6.4% after colon resection, comparable to the rates from the literature that vary from to 6.5% (11,18-20). When comparing outcomes in elective and non-elective settings, anastomotic leakage rates showed a slight, but clinically irrelevant, rise from 6.4 to 7.1%. However, mortality rates almost tripled from.4 to 8.5% in the non-elective setting. This implies that although anastomotic leakage is still a major contributor to mortality (1,11,18), many patients die due to other causes. COMPARISON TO PREVIOUS STUDIES Previous studies on thirty-day mortality after colorectal cancer surgery based on comparable population-based databases showed similar results (21-24). A Danish study focused on hospital variation in mortality and showed that variation in mortality rates was highest in patients undergoing non-elective surgery. Hospitals with the highest mortality rates treated the oldest patients as well as patients with a higher American Society of Anesthesiologists classification and more advanced tumour stage (21). The French study also showed a higher mortality rate in nonelective surgery, with high age, malnutrition and comorbidity as independent risk factors for mortality (22). Research in the benign surgical field described risk factors for post-operative mortality after non-elective surgery for diverticular disease. They also identified patient factors such as higher age and comorbidity as independent risk factors (25). In concordance with this, the present study also shows that factors leading to mortality are mostly patient and tumour characteristics and are less often treatment factors. Our results showed patient factors such as 50

12 Mortality rates after non-elective colon cancer resection higher age, high American Society of Anesthesiologists classification and higher Charlson score as risk factors for mortality (7,26). In addition, tumour factors such as tumour perforation (27) and a right-sided-colon tumour were independent risk factors for mortality (,15,28). Right colectomy is a frequently performed operation and is one of the first abdominal procedures taught to surgical residents in the Netherlands. A large American database study comparing rightand left-sided resections in an elective setting did not show any differences in postoperative outcome, despite the fact that in this study patients undergoing right-sided resection were older and had more comorbidity (29). In a non-elective setting, right-sided resection is the type of colectomy associated with the highest odds for mortality (,15). This might be caused by a potentially worse condition in right colon cancer patients during an acute setting, such as a poor general condition, a deficient nutritional state and a more advanced tumour stage (12,1). These suggestions are in concordance with our data. Patients undergoing right-sided resection in our cohort were more often older, had a higher American Society of Anesthesiologists classification, higher Charlson score and a more advanced tumour stage. Furthermore, most patients with a body mass index <20, what might been seen as an indicator of low nutritional status, underwent right-sided resection (data not shown). The worse outcome in non-elective surgery might not only be explained by a poor preoperative state of patients but also because surgery in a nonelective setting is frequently performed during the evening and night shifts, sometimes by surgeons with less disease-specific expertise. Some studies suggested that experience and caseload of an individual surgeon are predictors for postoperative mortality (0,1). Unfortunately, our dataset does not contain information on caseload per surgeon. Surgical approach is another treatment factor influencing surgical outcome in the present study. Laparoscopic resection is associated with significant less mortality, also after correction for confounders (22,2). Low mortality after laparoscopy could be caused by selection bias, but it could also be a valid reflection of reality due to inclusion of an entire population also including high-risk patients, who might benefit the most from minimal invasive surgery (,4). In non-elective setting thirteen percent of patients underwent laparoscopic resection, not leading to a significant difference in mortality rate. A previous performed French population study showed comparable results with lower mortality after laparoscopic surgery with more benefit in elective surgery compared to emergency surgery (22). In the present study the absence of survival benefit of laparoscopy in non-elective setting might be explained by patient and tumour factors. Patients undergoing laparoscopy in non-elective setting were younger, had a lower American Society of Anesthesiologists classification, less often ct4 tumours and less often symptomatic tumours (data not shown). 51

13 Chapter STRENGTHS AND WEAKNESSES To our knowledge, the present study on non-elective colon cancer surgery is the first study comparing the outcome between left and right-sided colon cancer resection in a non-elective setting. Furthermore, the present results are based on a nationwide database with an almost complete registration in which all Dutch hospitals performing colorectal surgery participated. Moreover, the collected data has a high concordance in its validation against the National Cancer Registry (16,17). The advantage of using data from a national database is that results are based on all patients operated for colorectal cancer in the Netherlands and that there are no patient selection criteria as in most clinical trials, in which non-elective patients are often excluded. However, there are some limitations that deserve mention. The database of the DSCA only contains data of patients operated on for malignancy, so the outcomes may not apply in colorectal patients with benign conditions. Another limitation, as with all large databases, is that there may be a bias due to inaccuracies in defining variables. Because the DSCA is intended for a nationwide audit, ambiguities in definitions are minimized by supplying suggestions during registration. Additionally, the definition of non-elective surgery can be indistinct. A large proportion of the patients in our cohort were operated in a non-elective setting but had no registered preoperative tumour symptoms. This may be due to registration errors or unclear predefined categories. As a control to our outcomes, we performed the aforementioned analysis on patients with registered symptoms only, which did not show significantly different results. Furthermore, a large amount of patients with symptomatic tumours were operated in an elective setting. It may be that symptoms in these patients were relatively minor. Unfortunately, we did not have information on this. Future research on preoperative optimization of patients could be a valuable contribution. Another deficiency in the database is the lack of intraoperative data regarding the duration of operation, intraoperative blood loss, the use of preoperative bowel preparation, intraoperative bowel lavage and intraoperative complications. These additional parameters could be valuable in the identification of possible risk factors for outcomes in colon cancer surgery. In the future, the DSCA will focus on these items as well. CLINICAL IMPLICATIONS AND FURTHER RESEARCH Clinical management of symptomatic colon cancer remains a difficult challenge. High rates of postoperative mortality suggest that it is the best option to operate shortly after diagnosis to prevent colon tumours from becoming symptomatic and thereby preventing non-elective surgery. Therefore, short waiting lists are crucial. Patients requiring non-elective surgery should 52

14 Mortality rates after non-elective colon cancer resection be optimized preoperatively and preferably be operated on by a dedicated team. A dedicated team is of great value because it is known that an acute presentation of a colon tumour is not only associated with short term complications but also has a worse oncological outcome (,4). Acute surgery for colon cancer is therefore as much about adequate management of the complication, such as an ileus or perforation, as it is about preserving oncological principles. Management and outcome of obstructed tumours have been thoroughly investigated (8,5). Optimization prior to surgery by creation of a temporary defunctioning stoma or placement of a stent as a bridge to surgery provide good solutions in these circumstances (8,9). Additionally, intra-operative deviation by means of a Hartmann resection or primary anastomosis with a defunctioning stoma showed good results, especially in left-sided colon resections (8,15). Studies comparing the outcome of obstructed and perforated tumours showed both higher morbidity and mortality in patients with tumour perforations (5,6), which is also confirmed in our results. Tumour perforation was an independent risk factor for mortality; tumour obstruction did not influence the mortality rate in non-elective surgery. The treatment of patients with a tumour perforation remains challenging. Patients with intraperitoneal perforations often require immediate surgical intervention, while the patient is in suboptimal condition, suffering peritonitis, septic shock, and with the additional presence of a malignant disease. Deviation by means of a defunctioning stoma or exteriorization of the colon, in which the affected bowel part is brought outside the abdomen, might be an alternative for direct resection of the perforated tumour in patients with colon cancer. After exteriorization, another operation is necessary to excise the tumour. This second surgery could be performed within several days in more optimized patients. The present study showed that stomas, both defunctioning and terminal, were significantly more often created in non-elective surgery. In patients with a perforated tumour, only half of the patients had a primary anastomosis. Stoma construction, especially end-ileostomy, was associated with a higher mortality rate. These outcomes can be well explained because the construction of a stoma during non-elective colon surgery is mostly performed for patients with an advanced tumour stage or a severely poor condition. There is not much information in the literature about patients presenting with bleeding colon tumours. Patients with a bleeding tumour could be optimized by transfusion prior to surgery. Unfortunately, our database does not contain information on preoperative optimization, laboratory results and transfusions of patients presenting with symptomatic tumours. Theoretically, patients presenting with severe anemia due to a colon tumour might also be eligible 5

15 Chapter for a single dose of neoadjuvant radiation to stop the tumour from bleeding and optimize the patient prior to resection. However, there is no supporting literature on this theory. CONCLUSION Non-elective colon cancer resection is associated with high postoperative mortality. In particular, patients presenting with tumour perforation and patients requiring right-sided non-elective resection have a high mortality risk. Clinical anastomotic leakage is an independent predictor for postoperative death, particularly in a non-elective setting. Patients should be operated in an early timeframe after diagnosis to prevent tumours from becoming symptomatic and to avoid nonelective surgery. Hopefully, the recently implemented national colon screening programme will reduce the non-elective surgery rate. 54

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