Characteristics of incidental prostate cancer in the United States

Abstract

Background: Data regarding North-American incidental (cT1a/b) prostate cancer (PCa) patients is scarce. To address this, incidental PCa characteristics (age, PSA values at diagnosis, Gleason score [GS]), subsequent treatment and cancer-specific survival (CSS) rates were explored. Methods: Incidental PCa patients were identified within the Surveillance, Epidemiology, and End Results (SEER) database (2004-2015). Descriptive statistics, annual percentage changes (EAPC), Kaplan-Meier estimates, as well as Cox regression models were used. Bootstrapping technique was used to generate 95% confidence intervals for CSS at 6 years. Results: Of all 344,031 newly diagnosed non metastatic PCa patients, 5155 harbored incidental PCa. Annual rates of incidental PCa increased from 1.9% (2004) to 2.5 % (2015; p = 0.02). PSA values at diagnosis were 0-4 ng/ml in 48% vs. 4-10 ng/ml in 31% vs. > 10 ng/ml in 21%. Of all incidental PCa patients, 64% harbored GS 6 vs. 25% GS 7 vs. 11% GS >= 8. Of all incidental PCa patients, 47% were aged < 70, 35% were between 70 and 79 and 18% were >= 80 years. Subsequently, 71% underwent no local treatment (NLT) vs. 16% radical prostatectomy (RP) vs. 14% radiotherapy (RT). Proportions of patients with NLT increased from 65 to 81% (p = 0.0001) over the study period (2004-2015). CSS at six years ranged from 58% in GS >= 8 patients with NLT to 100% in patients who harbored GS 6 and underwent either RP or RT. Conclusion: Incidental PCa in the United States is rare. Most incidental PCa patients are diagnosed in men aged less than 80 years of age. The majority of incidental PCa patients undergo NLT and enjoy excellent CSS.