Obesity is a risk factor for multifocal disease and recurrence after colorectal cancer surgery: a case-control study.

Background: Several studies have demonstrated that obesity is a risk factor for colorectal cancer (CRC), but few data are available regarding its role in multifocal disease and postoperative recurrence. The present study aimed to assess the role of obesity as a risk factor for multifocal disease and postoperative recurrence in patients with CRC. Patients and Methods: The records of 940 consecutive patients with CRC admitted to three surgical centres between January 2006 and January 2011 were retrospectively analysed. The 595 individuals whose preoperative body mass index (BMI) values were available were included in the study. Following WHO guidelines, the patients were stratified into four groups depending on their BMI values. Age at disease onset, clinical presentation, tumor invasiveness, the presence of multiple foci, and the colon cancer recurrence rate in the four groups were assessed and compared. Results: At multivariate analysis, diagnosis of familial adenomatous polyposis ( PAP) and a BMI>30 were found to be independent predictors of synchronous polyps (Odd Ratio [OR]=10.7, 95% Confidence interval (CI)=2-75, p=0.005; and OR=2.2, 95% p=0.003, respectively). The cancer recurrence rate in the patients with stage 2 CRC was significantly higher in the obese with respect to the non-obese (p=0.05). At multivariate analysis, BMI>30, FAP, and positivity by the Bethesda criteria were found to be independent predictors of recurrence after CRC surgery. Conclusion: Obese patients diagnosed with CRC require throrough colonic exploration prior to surgery and necessitate more frequent postoperative endoscopic examinations with respect to patients without any risk factors.