The Impact of Agent Orange Exposure on Prostate Cancer Outcomes

Abstract

PurposeThis study explores the effect of Agent Orange (AO) exposure on prostate cancer (PCa) survival in Veterans Affairs (VA) patients receiving androgen deprivation therapy (ADT) for advanced PCa. Materials and MethodsWe retrospectively examined the association between AO exposure in men with PCa being treated with ADT in national VA databases. Patients were diagnosed with PCa from 2000-2008 with follow-up through May 2016. Clinical, pathologic and demographic variables were compared by AO exposure. Associations between AO and overall survival (OS), skeletal related events (SRE), and cancer specific survival (CSS) were performed using adjusted Cox proportional hazard models after inverse propensity score weighted (IPSW) adjustment. ResultsOverall, 87,344 patients were identified. AO exposed (n=3,475) were younger (p<0.001), had lower PSAs (p=0.002), and more likely to receive both local therapy and chemotherapy (p<0.001) compared to non-exposed (n=83,869). Charlson Comorbidity Indices were similar between groups (p=0.40). After IPSW adjustment, AO exposure was associated with improved OS (HR 0.84, 95% CI 0.73-0.97, p=0.02); however, no difference in risk of SRE (HR 1.04, 95% CI 0.80-1.35, p=0.77) or CSS (HR 0.79, 95% CI 0.60-1.03, p=0.08) was observed. ConclusionsAO exposure was associated with decreased risk of death in men receiving ADT for advanced PCa and does not appear to be associated with worse oncologic outcomes.