Age, comorbidity should inform decisions on how to treat low- or intermediate- risk prostate cancer

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

Specifically, risk for other-cause mortality increased with the number of major comorbid conditions, particularly in older men, the study noted. Prostate cancer mortality varied according to disease risk but not by number of comorbid conditions.

Researchers conducted a nationally representative, population-based, prospective cohort study among 3,183 men with nonmetastatic prostate cancer. Data were drawn from the Prostate Cancer Outcomes Study, a population-based cohort of men diagnosed with prostate cancer reported to the National Cancer Institute Surveillance, Epidemiology and End Results program.

Results were published in the May 21 Annals of Internal Medicine.

Fourteen-year cumulative other-cause mortality rates were 24%, 33%, 46% and 57% for men with zero, one, two and three or more comorbid conditions, respectively. For men diagnosed at age 65 years, subhazard ratios for other-cause mortality among those with one, two or three or more comorbid conditions versus none were 1.2 (95% CI, 1.0 to 1.4), 1.7 (95% CI, 1.4 to 2.0), and 2.4 (95% CI, 2.0 to 2.8), respectively.

Among men with three or more comorbid conditions, 10-year mortality rates for other causes were 26%, 40% and 71% for those age 60 or younger, those age 61 to 74, and those age 75 or older at diagnosis, respectively. Prostate cancer-specific mortality was 3% in patients with low-risk disease, 7% for those with intermediate-risk disease and 18% for those with high-risk disease. It varied by 10% to 11% among all numbers of comorbid conditions.

Aggressive therapy may benefit men with little or no comorbid disease, but it is not as valuable in men with more comorbidities, a competing-risks model suggested. Men with zero or one comorbid condition who were managed conservatively had increases of 2.4 (95% CI, 1.6 to 3.5) and 2.2 (95% CI, 1.5 to 3.3), respectively, in the subhazard of prostate cancer mortality compared with those treated aggressively. Men with two comorbid conditions (hazard ratio [HR], 1.6; 95% CI, 1.0 to 2.7) or three or more comorbid conditions (HR, 1.5; 95% CI, 0.9 to 2.5) who were managed conservatively did not have a statistically significant increase in prostate cancer mortality.

Researchers also conducted an analysis that included men who chose androgen deprivation therapy as primary treatment in the aggressive management group in order to explore the decision of any therapy versus none. The results were virtually identical, except for those from the competing-risks model analyzing the subhazard of prostate cancer mortality associated with no treatment. Although men with no comorbid conditions still had an increased risk (HR, 2.0; 95% CI, 1.3 to 3.0), men with one (HR, 1.1; 95% CI, 0.7 to 1.9), two (HR, 1.2; 95% CI, 0.7 to 2.2), or three or more (HR, 1.1; 95% CI, 0.6 to 2.0) comorbid conditions were not at increased risk.

The authors wrote, “These data provide a basis on which to counsel men about their risk for prostate cancer-specific and other-cause mortality and are based on simple variables commonly available to the clinician at the time of treatment decision: age, number of major comorbid conditions at diagnosis, and tumor risk. Older men with multiple major comorbid conditions should be informed of their higher probability of death from other causes before deriving a survival benefit from surgery or radiation therapy for low- and intermediate-risk disease.”