Effect of age, tumor risk, and comorbidity on competing risks for survival in a U.S. population-based cohort of men with prostate cancer

Abstract

Background: Accurate estimation of life expectancy is essential to offering appropriate care to men with early-stage prostate cancer, but mortality risks associated with comorbidity are poorly defined.

Objective: To determine the effect of age, comorbidity, and tumor risk on other-cause and prostate cancer-specific mortality in men with early-stage disease.

Design: Prospective cohort study.

Setting: A nationally representative, population-based cohort.

Patients: 3183 men with nonmetastatic prostate cancer at diagnosis.

Measurements: Baseline self-reported comorbidity (scored as a count of 12 major comorbid conditions), tumor characteristics, initial treatment, and overall and disease-specific mortality through 14 years of follow-up. Survival analyses that accounted for competing risks were performed.

Results: Fourteen-year cumulative other-cause mortality rates were 24%, 33%, 46%, and 57% for men with 0, 1, 2, and 3 or more comorbid conditions, respectively. For men diagnosed at age 65 years, subhazard ratios for other-cause mortality among those with 1, 2, or 3 or more comorbid conditions (vs. none) were 1.2 (95% CI, 1.0 to 1.4), 1.7 (CI, 1.4 to 2.0), and 2.4 (CI, 2.0 to 2.8), respectively. Among men with 3 or more comorbid conditions, 10-year other-cause mortality rates were 26%, 40%, and 71% for those aged 60 years or younger, 61 to 74 years, and 75 years or older at diagnosis, respectively. Prostate cancer-specific mortality was minimal in patients with low-risk (3%) and intermediate-risk (7%) disease but appreciable in those with high-risk disease (18%) and did not vary by number of comorbid conditions (10% to 11% in all groups).

Limitation: Comorbid conditions were self-reported.

Conclusion: Older men with multiple major comorbid conditions are at high risk for other-cause mortality within 10 years of diagnosis and should consider this information when deciding between conservative management and aggressive treatment for low- or intermediate-risk prostate cancer.

Primary funding source: National Cancer Institute.

Appendix Figure. Study flow diagram

PCOS = Prostate Cancer Outcomes Study.

Figure 1

Cumulative incidence curves for other-cause and prostate cancer–specific mortality, by number of comorbid conditions.

Figure 2

Competing-risks model depicting cumulative incidence of other-cause and prostate cancer–specific mortality, by number of comorbid conditions, for men aged <60 y (A and B), 60 to 70 y (C and D), and >70 y (E and F).

Figure 3

Competing-risks model depicting cumulative incidence of other-cause and prostate cancer–specific mortality, by D'Amico risk criteria, for men aged <60 y (A and B), 60 to 70 y (C and D), and >70 y (E and F).