Cardiovascular comorbidity linked to prostate cancer-specific mortality in elderly
MedWire News: Study results show that elderly prostate cancer patients with cardiovascular disease (CVD) are less likely to die from prostate cancer than those without the concurrent condition.
CVD was associated with an 80% reduced risk for prostate cancer-specific mortality (PCSM) among the US cohort, after adjusting for age, treatment, year of brachytherapy, and known prostate cancer prognostic factors.
Akash Nanda from Brigham and Women’s Hospital in Boston, Massachusetts, and colleagues, identified competing risks for PCSM among 1978 men with a median age of 71 years and intermediate-risk prostate cancer, defined as Gleason score 7, with a prostate-specific antigen (PSA) of 20 ng/ml or less, and tumor stage T2c or less. All patients had been treated with brachytherapy alone, or in conjunction with external beam radiotherapy (EBRT).
A total of 928 men had CVD. Of the 1050b men without CVD, 746 were treated with brachytherapy alone, and 304 underwent EBRT with a brachytherapy boost.
After a median follow-up of 3.2 years, 15 men died of prostate cancer and 184 died of other causes. Importantly, in the men without CVD, 13 (12.7%) of 102 deaths were due to prostate cancer, compared with only two (2.1%) of 97 among men with CVD who died.
In multivariable analysis adjusting for covariables including CVD, age, treatment, PSA level, and tumor stage, the presence of CVD was significantly associated with a decreased risk for PCSM with a hazard ratio of 0.20. Conversely, each unit increase in PSA level during follow-up gave a 1.14-fold increased risk for PCSM.
In men without CVD, a PSA level above the median of 7.3 ng/ml conferred a greater risk for PCSM compared with having a PSA below the median. The 7-year PCSM estimates for men with a PSA above or equal to 7.3 ng/ml were 4.8%, compared with 0.5% for men with a PSA below the median.
By contrast, a PSA level above or below the median conferred no difference in PCSM risk for men with CVD.
“This suggests that in the design of future prospective studies... prerandomization stratification should be considered because the treatment effect, similar to prognostic factors like pre-treatment PSA level, may differ in men with and without CVD,” conclude the researchers in the International Journal of Radiation Oncology Biology Physics.
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By Sarah Guy