Men with higher-risk prostate cancer more likely to die from other causes

Men with low-risk prostate cancer have better other-cause survival than those with higher-risk disease even after controlling for lifestyle characteristics and comorbidities, a study has shown.

“Men with prostate cancer have high cause-specific survival, and most deaths are from other causes,” the investigators said.

To examine other- and all-cause mortality, the investigators selected men diagnosed with prostate cancer from 1994 to 2014 from the Prostate, Lung, Colorectal and Ovarian Cancer (PLCO) Screening Trial cohort. Other- and all-cause survival were assessed by prostate cancer risk level, defined as the D’Armico categories for localized disease (low, intermediate, and high risk) plus nonlocalized disease.

Three Cox proportional hazards models were developed to evaluate the association 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; and model III additionally controlled for initial treatment.

A total of 76,672 men participated in the PCLO study, of whom 10,859 had prostate cancer. Of the latter cases, 9,248 (85.2 percent) had known prostate cancer risk level (mean age 70.4±6.2 years). Median follow-up time from diagnosis was 10.8 years (interquartile range, 6.8–15.0).

Overall, 3,318 deaths occurred, of which 81 percent were from other causes. Compared to the low-risk group, higher-risk groups had greater other-cause mortality in model II (intermediate risk: hazard ratio [HR], 1.13, 95 percent confidence interval [CI], 1.04–1.23; high risk: HR, 1.35, 95 percent CI, 1.21–1.50; advanced disease: HR, 1.63, 95 percent CI, 1.35–1.97).

HRs in model III were comparable to those in model II, except for advanced disease where the HR decreased to 1.35.

“Further research is needed to identify factors contributing to this higher other-cause mortality to help mitigate the risk,” the investigators said.