EP1009 - Outcomes of Rectal Cancer Surgery After Prior Prostate Cancer Treatment: A Single-Institution Matched Retrospective Analysis

Purpose/Background: Prior prostate cancer treatment, including prostatectomy or pelvic radiation, can distort pelvic planes and impair vascularity, complicating subsequent rectal cancer surgery. Studies have shown that patients-especially those exposed to pelvic radiation-experience higher rates of anastomotic leak, permanent stoma, and local recurrence. However, recent registry data suggest that prostate cancer history may not worsen oncologic outcomes. Given these mixed findings, we evaluated perioperative and oncologic outcomes among patients with and without prior prostate cancer treatment at a tertiary academic center.

Methods/Interventions: We retrospectively reviewed all patients undergoing rectal cancer resection at a tertiary academic center between 2021 and 2025. Of 642 patients, 34 (5.3%) had a history of prostate cancer. After inclusion criteria requiring definitive prostate cancer treatment (surgery and/or pelvic radiation) and rectal cancer resection excluding local or transanal excision, 13 patients remained. These patients with a history of treated prostate cancer were propensity score matched 1:3 to 39 controls without prior prostate cancer based on age, sex, body mass index, neoadjuvant therapy, rectal tumor location (upper vs. mid/lower), and T stage (T1-2 vs. T3-4) using nearest-neighbor matching. The primary outcome was major postoperative morbidity (Clavien-Dindo ≥III). Secondary outcomes included anastomotic leak, 30-day readmission, operative time, conversion to open surgery, hospital length of stay, permanent ostomy, local recurrence, and overall survival. Wilcoxon rank-sum tests were performed on continuous variables, and Fisher's exact tests were performed on categorical variables.

Results/Outcomes: After matching, baseline characteristics were similar between groups. There were no significant differences in major morbidity, operative time, conversion rate, anastomotic leak, length of stay, readmission, or permanent ostomy. Median operative time was longer in patients with a history of prostate cancer (378 vs 298 minutes, p=0.08). Local recurrence was also higher (27.3% vs 5.1%, p=0.06), though not statistically significant, likely reflecting small sample size. Overall survival was not statistically different between groups (15.4% vs 2.6% mortality, p=0.15) (Table 1).

Conclusion/Discussion: In this small matched cohort, differences in outcomes for rectal cancer patients with prior prostate cancer therapy did not reach statistical significance. Patients with prior prostate cancer trended toward longer operative times and higher local recurrence rates, outcomes that may reflect increased operative complexity, altered pelvic anatomy, limitations in neoadjuvant therapy, and difficulty obtaining R0 resection status. Larger multi-institutional studies are warranted to further explore these findings and to suggest alternate approaches for improving outcomes in this very challenging group of patients.

Perioperative and Oncologic Outcomes After Rectal Cancer Resection in Patients With and Without a History of Prostate Cancer
Table 1: Perioperative and oncologic outcomes after rectal cancer resection in patients with and without prior prostate cancer treatment. IQR: interquartile range.