Effects of obesity in rectal cancer surgery

Increased local recurrence after total mesorectal excision (TME) in obese rectal cancer patients has been attributed to technical difficulties associated with adiposity. In this study, we evaluate whether higher body mass index (BMI) compromises surgical resection in patients with locally advanced, mid-to-low rectal cancer after neoadjuvant therapy, adversely affecting long-term oncologic outcomes.

Five-hundred and ninety-six patients with uT3/4 and/or uN1 rectal adenocarcinoma were treated from 1998 to 2007 with neoadjuvant therapy, followed by radical resection using TME. Outcomes were analyzed according to BMI: obese (BMI >or=30) and nonobese (BMI <30). Median follow-up was 39 months.

In all, 26.7% of patients were obese. The rate for positive circumferential margin in nonobese was 4.9% versus 2.5% in obese (p = 0.21). The sphincter-sparing rate in nonobese was 79.5% versus 80.5% in obese (p = 0.77). Five-year overall survival for nonobese was 84% versus 90% for obese (p = 0.92). Five-year disease-free survival for nonobese was 76% versus 73% for obese (p = 0.75). Operative time was longer in obese than nonobese; 4.3 versus 3.7 hours, respectively (p < 0.01). Length of stay was longer in obese than nonobese; 8 versus 7 days, respectively (p < 0.01). Similar results were obtained in analysis stratified by gender.

After neoadjuvant therapy for mid-to-low rectal cancer, higher BMI did not compromise sphincter preservation or complete resection or negatively affect long-term outcomes. These findings might be related to the fact that resection was performed in a specialty center with dedicated oncologic surgeons. However, higher BMI was associated with longer operative time, indicating a more technically demanding procedure and longer hospital stay.