Race and mortality risk after radiation therapy in men treated with or without androgen-suppression therapy for favorable-risk prostate cancer

Despite all of the above, use of ADT in American black men with favorable-risk disease has some intuitive appeals, the authors say. They are more likely than white counterparts to harbor occult high-grade/stage prostate cancer. The hope is that ADT would attack hidden and dangerous disease in some men and thus extend life in such cases.

Because of this complex tableau, Dr Kovtun and colleagues initiated their new study to find out what has gone on when black men with good-risk disease received ADT before radiotherapy.

These authors should be “applauded” for investigating these circumstances, said an expert not involved with the study.

The “study highlights the importance of tailoring therapeutic interventions to individual patients,” said Claire Brady, MD, a medical oncologist at Cork University Hospital in Ireland, who was approached for comment.

“Incredible gains” have been made in improving prostate cancer survival via treatment, she said. However, over time, as the “margin of benefit has become smaller,” Dr Brady said, “the risk of doing more harm than good significantly increases.”

“This study emphasizes the importance of taking into consideration the risk of an individual’s co-morbid risk factors,” she told Medscape Medical News in an email.

No Problem Among Men Not Treated with ADT

As noted above, there was a significant association between black race and an increased risk for all-cause mortality.

The same was also true for other-cause mortality (aHR, 1.86; 95% CI, 1.08 – 3.19; P = .024) among black men vs nonblack men who received ADT.

Importantly, this association between black race and mortality was not found among the men who were not treated with ADT (aHR for all-cause mortality, 1.33 [95% CI, 0.93 – 1.91; P = .12]; aHR for other-cause mortality, 1.39 [95% CI, 0.96 – 2.02; P = .08]).

These multivariate analyses adjusted for the age at brachytherapy, year of brachytherapy, cardiometabolic comorbidity status (history of myocardial infarction, heart failure, or diabetes), risk group, and ADT treatment propensity score.

The authors highlight the fact that the median follow-up for black men receiving ADT was significantly shorter than that for nonblack men (6.12 vs 9.62 years). Thus, there was less time for black men receiving ADT to acquire mortality events, yet a significant association with an increased risk for mortality was observed anyway.

So, a question arises: Why are black men at risk for death from ADT treatment?

Comorbidities are a likely answer because the black men in the study were more likely to have significant cardiometabolic comorbidity. However, the authors adjusted for cardiometabolic comorbidity in their multivariate analysis.

Thus, the authors conclude that “cardiometabolic comorbidity alone does not appear to be sufficient to explain the significant increase” in mortality risk.

The team speculates that other factors, such as noncardiometabolic comorbidity, socioeconomic status, and health insurance status, may have affected the results.

But, as with many studies that are not prospective, randomized clinical trials, the researchers conclude that more study is needed to both confirm the findings and further understand what drives the problem at hand.

The authors and Dr Brady have disclosed no relevant financial relationships.

Cancer. Published online August 4, 2016. Abstract