Treatment of rectal cancer after previous prostate cancer: A single institution experience.

Clinical guidelines typically recommend a combination of chemotherapy, radiotherapy and surgery for the management of newly diagnosed rectal cancer. However, standard-of-care treatment may be high risk or not feasible after prior treatment for prostate cancer. Very few case reports describe outcomes or treatment options in this instance. The aim of the present retrospective study was to determine local treatment patterns and outcomes in patients with this diagnosis. The study population consisted of patients with rectal cancer who were treated at Westmead Hospital (Western Sydney, Australia) between January 2008 and January 2020, and had a background of previously treated or synchronous prostate cancer. A review of electronic medical records was conducted and a descriptive analysis was performed. In total, 15 (6.4%) male patients with rectal cancer had a synchronous or previously treated prostate cancer. Stage II, III and IV rectal cancer was recorded in 60.0, 26.7 and 13.3%, respectively. Overall, 8 patients had previously received definitive intent radiotherapy and did not receive neoadjuvant radiotherapy for their rectal cancer. After a median follow-up time of 2.4 years, 25.0% had experienced loco-regional recurrence and the overall survival rate was 87.5%. A total of 3 patients with higher-stage disease underwent neoadjuvant chemotherapy without radiotherapy, resulting in three R0 resections and no recurrences, at the time of data cut-off. At the centre in the present study, prior prostate cancer affected treatment decisions for newly diagnosed rectal cancer. Neoadjuvant chemotherapy was well tolerated and is an option for patients with stage III disease. Outcomes in patients who did not receive neoadjuvant radiotherapy were acceptable but with high rates of loco-regional recurrence. These findings provide some guidance for other clinicians when making decisions regarding treatment of this challenging disease.