Does IBD Portend Worse Outcomes in Patients with Rectal Cancer? A Case-Matched Analysis

BACKGROUND: Patients with IBD are at increased risk for developing colorectal cancer. However, overall survival and disease-free survival for rectal cancer alone in patients with IBD has not been reported. OBJECTIVE: This study aimed to determine overall survival and disease-free survival for patients with rectal cancer in IBD versus non-IBD cohorts. DESIGN: This is a retrospective cohort study. SETTING: This study was conducted at an IBD referral center. PATIENTS: All consecutive adult patients with IBD diagnosed with rectal cancer and at least 1 year of postsurgery follow-up were included and matched in a 1:2 fashion (age, sex, preoperative stage) with patients with rectal cancer who did not have IBD. MAIN OUTCOMES MEASURES: Five-year overall survival and disease-free survival, 30-day postoperative complication, readmission, reoperation, and mortality rates were measured. METHODS: Survival rates were calculated using Kaplan-Meier estimates. The association of risk factors and long-term outcomes was assessed using Cox proportion hazard models. RESULTS: A total of 107 study patients with IBD who had rectal cancer were matched to 215 control patients; preoperative stages were as follows: 31% with stage I, 19% with stage II, 40% with stage III, and 10% with stage IV. Differences were observed (IBD vs non-IBD) in neoadjuvant chemotherapy (33.6% vs 52.6%,p= 0.001) and preoperative radiotherapy (35.5% vs 53.5%,p= 0.003). Postoperative complication rates were similar. On surgical pathology, patients with IBD had more lymphovascular invasion (12.9% vs 5.6%,p= 0.04) and positive circumferential resection margins (5.4% vs 0.9%,p= 0.03). On multivariable analysis, the diagnosis of IBD did not significantly impact long-term mortality (HR, 0.91; 95% CI, 0.53-1.57;p= 0.73) or disease-free survival (HR, 1.36; 95% CI, 0.84-2.21;p= 0.22). LIMITATIONS: This study was limited by its retrospective design and the use of single-center data. CONCLUSIONS: Patients have rectal cancer with IBD and without IBD have similar long-term and disease-free survival, despite lower rates of neoadjuvant treatment and higher margin positivity in patients with IBD. See Video Abstract at http://links.lww.com/DCR/B271.