Impact of age at diagnosis of de novo metastatic prostate cancer on survival

Abstract

Background: An older age at the diagnosis of prostate cancer has been linked to worse prostate cancer-specific survival (PCSS). However, these studies were conducted before the approval of many life-prolonging drugs. This study was aimed at describing outcomes in a contemporary cohort of men diagnosed with de novo metastatic prostate cancer (mPCa) and assessing associations with the age at diagnosis while controlling for known prognostic factors.

Methods: The Surveillance, Epidemiology, and End Results registry was used to identify men diagnosed with mPCa from 2004 to 2014. Men were classified by 4 age groups: ≤54, 55 to 64, 65 to 74, and ≥75 years. The median overall survival, PCSS, and restricted mean survival times for any-cause mortality and prostate cancer-specific mortality (PCSM) were calculated. Multivariable and subdistribution hazard ratios for PCSM according to age group and with controlling for race, marital status, and income were estimated.

Results: Compared with men aged ≤54 years, men aged ≥75 years experienced a mean PCSS at 5 years that was 6.7 months shorter (95% confidence interval [CI], 5.5-7.8 months). In multivariable analyses, men aged ≥75 years had a 49% increase in the rate of PCSM in comparison with those aged ≤54 years (95% CI, 1.39-1.60). The subdistribution hazard ratio for PCSM between these groups was 1.41 (95% CI, 1.32-1.50).

Conclusions: Age was found to be an independent predictor of shorter PCSS in men diagnosed with de novo mPCa even in an era with more effective therapies. Further work is needed to determine the reason for poor outcomes in older men with mPCa.

Keywords: age at onset; metastases; prostate cancer; survival.