A population-based study of complications after colorectal surgery in patients who have received Bevacizumab

Background — Patients receiving Bevacizumab, a vascular endothelial growth factor inhibitor used to treat metastatic colorectal cancer, may be at greater risk of complications after colorectal surgery because of impaired healing.

Objective — The purpose of this study was to describe population-based rates of complications of colorectal surgery after Bevacizumab treatment and evaluate the relationship between time since last treatment and risk of complications.

Design — This was a population-based retrospective cohort study using administrative and cancer registry data.

Settings — The study was conducted in Ontario, Canada.

Patients — Patients with metastatic colorectal cancer receiving Bevacizumab between January 2008 and December 2011 were followed for a year after treatment or until death.

Main Outcome Measures — Administrative data were used to identify patients who underwent colorectal surgery after initiation of Bevacizumab and to determine whether they experienced a complicated postoperative course. The relationship between time since last Bevacizumab treatment (≤28 d, 29 d to 3 mo, and >3 mo) and risk of postoperative complications was evaluated using logistic regression.

Results — Of the 2759 patients who received Bevacizumab for the treatment of metastatic colorectal cancer, 265 underwent a colorectal procedure after exposure. The majority had a bowel resection or repair with no stoma (47.5%) and had emergency surgery (61.1%). Overall, 96 (36.2%) had a complicated postoperative course, including 20.4% readmission, 12.5% wound complications, and 7.9% mortality rate within 30 days of surgery. Adjusted multivariate analysis showed no difference in the likelihood of a complicated postoperative course among patients undergoing surgery within 28 days of receiving their last Bevacizumab dose compared with 29 days to 3 months (OR = 1.23 (95% CI, 0.53-2.84), or 3 to 12 months (OR = 0.98 (95% CI, 0.46-2.09) after receiving Bevacizumab.

Limitations — Reliance on administrative data to measure complications limited the scope of this study.

Conclusions — Patients with metastatic colorectal cancer requiring colorectal surgery after exposure to Bevacizumab experience substantial morbidity and mortality. The risk of complications is not detectably associated with time since exposure.