Risk of cardiovascular mortality with androgen deprivation therapy in prostate cancer: A secondary analysis of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Randomized Controlled Trial

BACKGROUND

For men with radiation-managed prostate cancer, there is conflicting evidence regarding the association between androgen deprivation therapy (ADT) and cardiovascular mortality (CVM), particularly among those who have with preexisting comorbidities. The objective of this study was to analyze the association between ADT and CVM across patient comorbidity status using prospectively collected data from a large clinical trial.

METHODS

In total, 1463 men were identified who were diagnosed with clinically localized, intermediate-risk/high-risk prostate cancer (T2b-T4, Gleason 7-10, or prostate-specific antigen >10 ng/mL) from 1993 to 2001 and managed with either radiation therapy (RT) alone or RT plus ADT during the randomized Prostate, Lung, Colon, and Ovarian (PLCO) Cancer Screening Trial. Adjusted hazard ratios (aHRs) for cause-specific mortality (prostate cancer-specific mortality vs other-cause mortality-including the primary end point of CVM [death from ischemic heart disease, cerebrovascular accident, or other circulatory disease]) were determined using Fine and Gray competing-risk regression analysis and stratified by comorbidity history.

RESULTS

There was no difference in the risk of 5-year CVM between ADT plus RT and RT alone (2.3% vs 3.3%, respectively; aHR, 0.69; 95% CI, 0.38-1.24; P = .21) overall or on subgroup analysis among men with a history of ≥1 preexisting comorbidities (3.2% vs 5.3%, respectively; aHR, 0.83; 95% CI, 0.43-1.60; P = .58), ≥2 preexisting comorbidities (6.9% vs 8.3%, respectively; aHR, 0.95; 95% CI, 0.40-2.25; P = .90), or cardiovascular disease/risk factors (3.6% vs 4.3%, respectively; aHR, 0.85; 95% CI, 0.44-1.65; P = .63). These results were all similar when each component of CVM was analyzed separately-either cardiac, stroke, or other vascular mortality (P > .05).

CONCLUSIONS

This study provides prospectively collected evidence that the use of ADT plus RT, compared with RT alone, is not associated with an increased risk of CVM, even among subgroups of men who have preexisting comorbidities and cardiovascular disease.

Validation of a subclassification for high-risk prostate cancer in a prospective cohort

BACKGROUND

A subgroup of men with favorable high-risk prostate cancer (T1c with either a Gleason score of 4 + 4 = 8 and a prostate-specific antigen [PSA] level <10 ng/mL or a Gleason score of 6 and a PSA level >20 ng/mL) has been associated with improved outcomes in comparison with other standard high-risk patients. This study was designed to validate the prognostic utility of a subclassification for high-risk disease with a prospectively collected data set.

METHODS

This study identified 3033 men from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial who had been diagnosed from 1993 to 2001 with clinically localized prostate cancer-either intermediate-risk disease (clinical stage T2b-c, a Gleason score of 7, or a PSA level of 10 to 20 ng/mL) or high-risk disease (clinical stage T3-T4, a Gleason score of 8-10, or a PSA level >20 ng/mL)-that was managed with radical prostatectomy or radiation therapy. Multivariable logistic regression was used to calculate adjusted odds ratios (aORs) for pathological T3 to T4 or N1 (pT3-T4/pN1) disease. Fine and Gray competing risks regression was used to determine adjusted hazard ratios (aHRs) of prostate cancer-specific mortality (PCSM).

RESULTS

The median follow-up was 5.7 years. Patients with favorable high-risk disease had lower 8-year PCSM in comparison with patients with standard high-risk disease (2.2% vs 10.8%; aHR, 0.26; 95% confidence interval [CI], 0.09-0.73; P = .01) but similar PCSM in comparison with patients with intermediate-risk disease (2.2% vs 2.2%; aHR, 0.90; 95% CI, 0.32-2.54; P = .84). Among those who underwent surgery, those with favorable high-risk disease had lower odds of pT3-T4/pN1 disease than those with standard high-risk disease (46.2% vs 63.3%; aOR, 0.50; 95% CI, 0.27-0.94; P = .03).

CONCLUSIONS

This study validates the prognostic utility of a subclassification for high-risk disease in a prospectively collected patient cohort. Patients with favorable high-risk disease have PCSM similar to that of patients with intermediate-risk disease and significantly better than that of patients with standard high-risk disease. Future trials are needed to assess possible de-intensification of therapy for favorable high-risk disease.