Incidence Of Second Primary Malignancies In Veterans After Prostate Cancer Diagnosis.

5093 Background: With the advancement of diagnostic and treatment modalities in prostate cancer (PC) over the past 20 years, PC specific survival rates have improved. The aim of this study was to evaluate the incidence of second primary malignancies in our veteran population after diagnosis of PC. Methods: We reviewed the records of 548 patients (pts) diagnosed with PC between 1999 and 2011. Data including demographics, veteran status (Vietnam vs. non-Vietnam), Gleason score, PSA, PC stage, treatment, incidence of second primary malignancy and survival were studied. Cox regression analysis was performed using SAS v 9.2. Results: There were 548 pts with a median (M) age of 71 years (45-98). 265 pts (48%) were Caucasian, 256 pts (47%) African American and 28 pts (5%) of other races; 158 pts (31%) were Vietnam veterans. The M Gleason score was 7 (4-10) and PSA 9.3 (0.7-7870). 153 pts (28%) had one or more second primary malignancies after PC diagnosis. The incidence of second malignancy was significantly higher among Vietnam veterans (OR: 2.08, p<0.0003) and pts with localized PC (OR: 5.53, p<0.0001) in univariate analysis. Sites for second malignancy were lung 42 (28%), hematologic 21 (14%), bladder 19 (12%), colorectal 11 (7%) and liver 10 (6.5%). Of the 95 pts who received radiotherapy for PC and later developed a second malignancy, 28 (29%) developed the second malignancy in the radiotherapy field (bladder, colon and rectal cancer) and 12 (11%) developed a hematologic malignancy. In 72 (47%) pts the second malignancy was diagnosed ≥4 years after the diagnosis of PC, 62 (41%) between 1-3 years and 18 (12%) within 12 months of the diagnosis of PC. Age (OR: 0.95, 95% CI: 0.93-0.97, p<0.0001), PC stage (OR: 0.18, 95% CI: 0.08-0.38, p<0.0001) and veteran status (Vietnam vs. non-Vietnam; OR: 1.65, 95% CI: 1.07-2.55, p<0.02) were independent and significant predictors of a second primary malignancy by multivariate analysis. Conclusions: In this cohort, 28% of veterans with prior PC developed a second primary malignancy. Vietnam veterans had 1.7 times greater risk to develop a second primary malignancy and patients with localized PC had 18% higher risk of developing a second primary malignancy compared to patients with metastatic PC.