Patient factors influencing conversion from laparoscopically assisted to open surgery for colorectal cancer

Background: Intraoperative conversion from laparoscopically assisted to open surgery for colorectal cancer is thought to be influenced by several patient factors. Analysis of the Conventional versus Laparoscopic-Assisted Surgery In Colorectal Cancer (CLASICC) Trial data aimed to identify these risk factors. Methods: Of 488 laparoscopically assisted procedures attempted, 143 (29·3 per cent) were converted to open operation. Patient factors considered in multivariable analyses were age, sex, previous abdominal incisions, body mass index (BMI), tumour site, tumour diameter, pathological tumour (pT) and pathological node (pN) stage, extent of tumour spread from the muscularis propria, liver and peritoneal metastases, and American Society of Anesthesiologists (ASA) grade. As BMI was missing for 30·7 per cent of patients, two approaches were employed: one considered BMI as a possible risk factor and one did not. Results: When BMI was taken into consideration, male sex (odds ratio (OR) 2·07; P = 0·020), BMI (OR 1·10; P = 0·006) and extent of tumour spread from the muscularis propria (OR 1·08; P < 0·001) were independent predictors of conversion. When BMI was not considered, extent of tumour spread (OR 1·07; P < 0·001) and male sex (OR 2·05; P = 0·004) were again identified, as were tumour site (OR 2·11; P = 0·005) and ASA grade (II versus I, OR 0·92; III versus I, OR 2·74; P = 0·012). Conclusion: Intraoperative conversion is more likely with larger BMI, in men, patients with rectal cancer, those graded ASA III or when there is greater local tumour spread