Improved Overall Survival in Prostate Cancer With Increasing Dose

Abstract

Purpose/Objective(s): Patients treated with radiation therapy for prostate adenocarcinoma (PCA) experience both acute and late genitourinary (GU) and gastrointestinal (GI) toxicity. Recent publications indicate a possible association between aspirin use and GI toxicity during radiation therapy for PCA. We sought to assess the effect of daily low-dose aspirin on acute and late GI and GU toxicity associated with radiation therapy for PCA in a large patient population. Materials/Methods: We queried an IRB-monitored, prospectively-acquired database of patients treated for PCA at our affiliated hospitals. For patients treated with definitive radiation therapy for PCA, we measured the association between aspirin use and Common Terminology Criteria for Adverse Events (CTCAE) GI/GU toxicity scores. Patient and treatmentrelated factors, such as age, race, total dose, T stage, hormonal therapy, use of pelvic nodal irradiation, length of time with acute toxicity records, and follow-up time were used as covariates. Univariate and multivariate analyses were performed using ordinal logistic regression models. Results: Between 1991 and 2013, 972 patients were eligible for analysis. 210 patients were on daily low-dose aspirin during treatment. On multivariate analysis, aspirin use was significantly associated with reduced acute GU toxicity (OR 0.73, 95% CI Z 0.55-0.99, p Z 0.040). There was no statistically significant worsening of acute GI (OR 0.77, 95% CI Z 0.581.03, p Z 0.079) or late GU toxicity (OR 0.93, 95% CI Z 0.69-1.25, p Z 0.632) associated with aspirin use. There was a trend for reduced late GI toxicity in patients taking daily aspirin (OR 0.69, 95% CI Z 0.48-1.01, p Z 0.056). Conclusions: Aspirin use was independently associated with reduced acute GU toxicity in patients undergoing radiation therapy for PCA. Late GU and GI toxicity were not worsened by aspirin use during radiation, and late GI toxicity trended towards improvement with aspirin use. While these results require validation in a prospective study, aspirin use during radiation therapy for PCA should be considered, as low-dose aspirin is a safe, inexpensive medication already separately recommended for many patients planned for radiation therapy. Author Disclosure: J.L. Mikell: None.W.A. Hall: None. D.C. Nickleach: None. N.K. Jegadeesh: None. P.J. Rossi: None. A.B. Jani: None.