Clinical Correlations between Treatment with Anticoagulants/Antiaggregants and Late Rectal Toxicity after Radiotherapy for Prostate Cancer

Aim: To assess variables related to grade 2 or higher late rectal toxicity (LRT) in prostate cancer treated with external radiotherapy. Patients and Methods: A retrospective analysis was carried out of 232 patients with T1-T3 prostate cancer treated with 3-dimensional conformal radiotherapy (3DCRT) (106 patients) or intensity modulated radiotherapy (IMRT) (126 patients) between June 2000 and May 2007. One hundred and seventy-seven patients received androgen deprivation therapy (ADT);fifty patients used anticoagulants/antiaggregants for vascular disease. Results: The median follow-up was 31 months (range, 6-79). At 5 years, the cumulative incidence of grade 2 or 3 LRT was 5.6%. On multivariate analysis, medication with anticoagulants/antiaggregants was correlated with grade 2 or 3 LRT (p=0.027), whereas age, National Comprehensive Cancer Network risk group classification, use of ADT, radiotherapy technique (3DCRT vs. IMRT) and total irradiated dose were not. Conclusion: Treatment with anticoagulants/antiaggregants appears to be a factor in grade 2 or 3 LRT.