Other and All-Cause Mortality among Men Diagnosed with Prostate Cancer in the PLCO Trial

Abstract

Men with prostate cancer have high cause-specific survival, and most deaths are from other causes. This study aimed to investigate other and all-cause mortality in a large cancer screening cohort. From the PLCO (Prostate, Lung, Colorectal and Ovarian) Cancer Screening Trial cohort, we selected men diagnosed with prostate cancer from 1994-2014. We examined other and all-cause survival by prostate cancer risk level, defined as the D'Amico categories for localized disease (low, intermediate and high risk) plus nonlocalized disease. We developed 3 Cox proportional hazards models to assess the relationship between risk level and survival. Model I controlled for age, race, study arm and diagnosis year. Model II additionally controlled for other demographic and medical history factors. Model III additionally controlled for initial treatment. Of 76,672 men in PLCO and 10,859 prostate cancer cases, 9,248 (85.2%) had known prostate cancer risk level (mean±SD age 70.4±6.2 years). Median followup time from diagnosis was 10.8 years (IQR 6.8-15.0). Of 3,318 deaths 81% were from other causes. Compared to the low risk group, other-cause mortality HRs were 1.13 (95% CI 1.04-1.23), 1.35 (95% CI 1.21-1.50) and 1.63 (95% CI 1.35-1.97) for intermediate risk, high risk and advanced disease, respectively, in model II. Model III HRs were similar to model II except for advanced disease, where the HR decreased to 1.35. Other-cause survival was greater in lower vs higher risk disease, even after controlling for lifestyle characteristics and comorbidities. Further research is needed to identify factors contributing to this higher other-cause mortality to help mitigate the risk.