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ADT decreases survival among black men with favorable-risk prostate cancer
Definitive treatment with androgen deprivation therapy increased the risk for death among black men with low- or favorable-risk prostate cancer, according to study results published in Cancer.
ADT should be reserved for black men with high-risk disease, according to the researchers.
Anthony V. D’Amico
ADT is frequently combined with radiation therapy for the treatment of men with intermediate- or high-risk prostate cancer. No evidence suggests that this treatment platform benefits patients with low- or favorable-risk disease.
“African American men are more likely than non–African American men to have comorbid illness that could interact with ADT and shorten survival,” Anthony V. D’Amico, MD, PhD, professor of medicine at Harvard Medical School and chief of genitourinary radiation oncology at Brigham and Women’s Hospital and Dana-Farber Cancer Institute, and colleagues wrote. “However, they are also more likely to harbor occult high-grade/stage prostate cancer despite low-risk prostate cancer indices, and ADT use is often required to maximize survival. Because of this dilemma, it remains unanswered whether the use of neoadjuvant ADT in favorable-risk prostate cancer to reduce prostate size and facilitate brachytherapy (but with no known curative benefit) is helpful or harmful in African American men.”
D’Amico and colleagues evaluated data from 7,252 men (median age, 68.1 years; interquartile range [IQR], 62.2-73.1) treated for low- or favorable-risk prostate cancer at the Chicago Prostate Cancer Center between October 1997 and May 2013.
All men received brachytherapy with (n = 1,501) or without (n = 5,751) neoadjuvant ADT for 4 months (IQR, 3-4).
Black men comprised 7.3% of the study cohort.
Risks for all-cause mortality, disease-specific mortality and other-cause mortality served as the study’s primary endpoint. The researchers defined follow-up as the period between the end of brachytherapy to either date of death or date of final data update.
Median follow-up for the entire cohort was 8.04 years (IQR, 5.62-10.9).
Black men tended to be younger (median age, 65.3 years vs. 68.4 years; P < .001); receive treatment later in the study period (median year of brachytherapy, 2007 vs. 2005; P < .001); have favorable-risk disease rather than low-risk disease (36% vs. 29.5%; P = .001); and have a baseline cardiometabolic comorbidity (27.8% vs. 23%; P = .01).
Owing to treatment delays, median follow-up was significantly shorter for black men, for both those who received ADT (6.12 years vs. 9.62 years; P < .001) and those who did not (6.16 years vs. 7.84 years; P < .001).
The researchers observed 869 deaths during follow-up: 48 deaths (5.52%) were attributable to prostate cancer, and the remaining 821 (94.48%) were due to other causes.
Multivariate analyses showed that black men who received ADT had an increased risk for all-cause mortality (adjusted HR = 1.77; 95% CI, 1.06-2.94) and other-cause mortality (adjusted HR = 1.86; 95% CI, 1.08-3.19).
In contrast, black men did not have a significantly increased risk for all-cause mortality (adjusted HR = 1.33; 95% CI, 0.93-1.91) or other-cause mortality (adjusted HR = 1.39; 95% CI, 0.96-2.02) if they did not receive ADT.
No disease-specific deaths occurred among black men included in the study cohort.
The researchers acknowledged study limitations, including the retrospective design and the significantly shorter follow-up period among black men who received ADT, which may have influenced the number of mortality events.
“The use of ADT in African American men should be reserved for treating higher-risk prostate cancer, for which level-one evidence supports its use,” D’Amico and colleagues wrote. “Further study of the biological basis of the increased mortality risk in African American men receiving ADT is warranted.” – by Cameron Kelsall
Disclosure: The researchers report no relevant financial disclosures.