Survival and peri-operative outcomes among patients with rectal cancer: the role of prior radiotherapy due to prostate cancer.

PURPOSE: Patients with rectal cancer (RCa) and prior radiation for prostate cancer (PCa) are clinically complicated and may have worse outcomes than other RCa patients. This study investigates the impact of previous radiation for PCa on survival for patients with RCa. METHOD: We conducted a population-based study identifying men who underwent surgical treatment of RCa from 2002 to 2010. Patients were classified into three cohorts: no prior PCa, prior PCa treated without radiotherapy, and prior PCa treated with radiotherapy. The primary outcome was overall survival. Secondary outcomes included RCa surgical approach, ICU admission, length of stay, ER visits, and delayed formation of a new stoma. RESULTS: Seven thousand ninety-six men underwent surgery for RCa; 6867 patients had no prior PCa, 58 had prior PCa treated without radiotherapy, and 171 had prior PCa treated with radiotherapy. The 5-year overall survival was 62% (95% CI 61-64%) for patients without prior PCa, 46% (95% CI 25-65%) for patients with prior PCa treated without radiotherapy, and 42% (95% CI 29-54%) for patients with prior PCa treated with radiotherapy (p < 0.0001). In multivariable analysis, patients with prior PCa treated with radiotherapy were at increased risk of death (aHR 1.38, 95% CI 1.12-1.69) compared to those without prior PCa. Furthermore, patients with prior PCa treated with radiotherapy had a significantly increased risk of resection with permanent stoma. CONCLUSIONS: Prior radiotherapy for PCa is a poor prognostic factor in RCa patients with significantly increased risk of death. Additionally, patients with prior radiotherapy for PCa are more likely to require a permanent stoma.