Risk factors for conversion in laparoscopic surgery for colorectal cancer

Purpose: Recently, laparoscopic surgery has been performed with increasing frequency in cases of various diseases, including colorectal cancer. However, in some cases, laparoscopic surgery should be converted to open procedures because of several factors. In this study, we tried to find the causes of and the risk factors for conversion to open procedures during colorectal cancer surgery. Methods: From June 2002 to May 2008, laparoscopic surgery in 324 patients who were diagnosed as having colorectal cancer was performed by two surgeons. Patients were divided into two groups, non-conversion and conversion groups. We investigated the differences in age, sex, presence of preoperative colonic obstruction, tumor invasion (pT stage), and so on between the two groups. Results: Of the 324 patients, 20 patients experienced an open conversion: 5 of 28 patients who had a colonic obstruction and 15 of 296 patients who had no obstruction (P=0.021). The causes of conversion during the surgery were tumor invasion, peritoneal adhesion, hemorrhage, and cancer perforation. There were 8 conversions out of 92 patients from June 2002 to May 2005 and 12 out of 232 from June 2005 to May 2008 (P=0.231). In regards to the degree of tumor invasion, 9 of 32 who were stage pT4 experienced a conversion to an open procedure (P<0.001). In multivariate analysis, the presence of a colonic obstruction and pT4 stage were meaningful risk factors for conversion to an open procedure. Conclusion: From this study, we can predict a higher rate of conversion to an open procedure in patients with locally advanced colon cancer, especially when a colonic obstruction is present. Therefore, a careful laparoscopic approach is needed in such patients.