Stage at presentation and oncologic outcomes for agent orange exposed and non-exposed United States veterans diagnosed with prostate cancer.
259 Background: Exposure of Vietnam War Veterans to the defoliant Agent Orange (AO) has been linked to increased tumor stage of Veterans diagnosed with prostate cancer. However, information on the effect of exposure to treatment outcomes is lacking. The goal of this study was to evaluate oncologic outcomes in Veterans based on AO exposure history, accounting for known prognostic covariates not previously studied. Methods: United States military Veterans diagnosed with prostate adenocarcinoma born between the years 1930-1956 were identified from a large professionally curated institutional database. Evaluable patients had to have known AO exposure status, age, NCCN risk group, Charlson comorbidity score, smoking status, and whether initial therapy was surgical, radiation, or systemic. Risk of death, metastasis, and progression stratified by the type of initial therapy received was analyzed using Cox regression. Results: There were 70 AO exposed and 561 non-exposed Veterans identified, with a median follow-up of 10.0 years. AO exposure Veterans (AOeV) were significantly younger (64.0 versus 65.7 years, p=0.013) at diagnosis and presented at more advanced stages (e.g. Stage 4: 14.3% versus 2.5%) than non-exposed Veterans (non-AOeV). There was no difference for overall survival (HR=0.86, p=0.576, metastasis-free survival (HR=1.5, p=0.212), or progression-free survival (HR=0.67, p 0.060) between AOeV versus non-AOeV in analyses stratified by treatment received accounting for other prognostic covariates. Cigarette smoking was associated with a 2- 3-fold increased risk of death over those who quit or never smoked. Conclusions: Although AOeV do present at younger age and higher clinical stages than non-AOeV, the oncologic outcomes after accounting for treatments received and other prognostic covariates are similar. The implication is that AOeV are more likely to be recommended multimodality or systemic therapies at presentation.