In a retrospective cohort study using Surveillance, Epidemiology, and End Results (SEER) data reported in JAMA Network Open, Elmehrath et al found that a substantial proportion of men diagnosed with metastatic prostate cancer between 2000 and 2016 in the United States died from causes unrelated to cancer.

As stated by the investigators, “Owing to improved survival among U.S. patients with metastatic prostate cancer, patients tend to live long enough after a prostate cancer diagnosis for non–cancer-related comorbidities to be associated with their overall survival. Although studies have investigated causes of death among patients with localized prostate cancer, data are lacking regarding causes of death among patients with metastatic prostate cancer.”

Study Details

The study involved SEER program data from a sample of 26,168 men who received a diagnosis of metastatic prostate cancer between January 2000 and December 2016. Standardized mortality ratios for causes of death were calculated by dividing the observed number of deaths for each cause of death in the study cohort by the expected number of deaths in the age-matched U.S. male population for the same period with adjustment for age and race/ethnicity.

Key Findings

Among the 26,168 patients: 48.9% were aged 50 to 70 years, with a mean age of 70.8 years at diagnosis of metastatic disease; 74.5% were White; and 72.7% were diagnosed with stage M1b disease. Median overall survival was 29 months (interquartile range = 13–63 months), with 1- and 5-year rates of 77.5% and 26.4%.

A total of 16,732 patients (63.9%) died during the follow-up period. Mean age at death was 74.1 years. Overall, 59.0% of deaths occurred within 2 years after diagnosis, 31.6% at 2 to 5 years, and 9.4% at more than 5 years.

Among the 16,732 deaths, 13,011 (77.8%) were from prostate cancer, 924 (5.5%) from other cancers, and 2,797 (16.7%) from noncancer causes. Among noncancer causes, the most common specific causes were cardiovascular disease (n = 1,147), chronic obstructive pulmonary disease (COPD)/associated conditions (n = 207), cerebrovascular disease (n = 198), and accidents and adverse effects of medications (n = 122); 575 deaths were classified as having “other” causes.

Overall, the standardized mortality ratio for death from cancer other than prostate cancer was 1.60 (95% confidence interval [CI] = 1.50–1.71). The overall standardized mortality ratio for all noncancer causes of death was 1.29 (95% CI = 1.24–1.33), including standardized mortality ratios of 1.32 (95% CI = 1.26–1.39), 1.27 (95% CI = 1.19–1.36), and 1.19 (95% CI = 1.08–1.31) at < 2, 2 to 5, and > 5 years after diagnosis, respectively. Overall, among the most common noncancer causes of death, standardized mortality ratios were 1.34 (95% CI = 1.26–1.42) for cardiovascular disease, 1.19 (95% CI = 1.03–1.36) for COPD, and 1.31 (95% CI = 1.13–1.50) for cerebrovascular disease.

The investigators concluded, “In this cohort study, deaths from noncancer causes, including cardiovascular disease, constituted a substantial number of deaths among men with metastatic prostate cancer. Therapy and follow-up should be tailored to the needs of each patient with metastatic prostate cancer, and counseling regarding future health risks should be provided.”

Omar Alhalabi, MD, of the Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, is the corresponding author for the JAMA Network Open article.

Disclosure: No external funding for the study was reported. For full disclosures of the study authors, visit jamanetwork.com.