Influence of Comorbidity on the Risk of Mortality in Men With Unfavorable-Risk Prostate Cancer Undergoing High-Dose Radiation Therapy Alone

To explore whether a subgroup of men with unfavorable-risk prostate cancer (PC) exists in whom high-dose radiation therapy (RT) alone is sufficient to avoid excess PC death due to competing risk from cardiometabolic comorbidity.

This was a cohort study of 7399 men in whom comorbidity (including congestive heart failure, diabetes mellitus, or myocardial infarction) was assessed and recorded with T1-3NxM0 PC treated with brachytherapy with or without neoadjuvant RT, October 1997 to May 2013 at a single providing institution. Cox and competing risks regression analyses were used to assess whether men with unfavorable-intermediate/high-risk versus favorable-intermediate/low-risk PC were at increased risk of PC-specific, all-cause, or other-cause mortality (PCSM, ACM, OCM), adjusting for number of comorbidities, age at and year of brachytherapy, RT use, and an RT treatment propensity score.

After a median follow-up of 7.7 years, 935 men died: 80 of PC and 855 of other causes. Among men with no comorbidity, PCSM risk (adjusted hazard ratio [AHR] 2.74 [95% confidence interval (CI) 1.49-5.06], P=.001) and ACM risk (AHR 1.30 [95% CI 1.07-1.58], P=.007) were significantly increased in men with unfavorable-intermediate/high-risk PC versus favorable-intermediate/low-risk PC, with no difference in OCM (P=.07). Although PCSM risk was increased in men with 1 comorbidity (AHR 2.87 [95% CI 1.11-7.40], P=.029), ACM risk was not (AHR 1.03 [95% CI 0.78-1.36], P=.84). Neither PCSM risk (AHR 4.39 [95% CI 0.37-51.98], P=.24) or ACM risk (AHR 1.43 [95% CI 0.83-2.45], P=.20) was increased in men with 2 comorbidities.

To minimize death from PC, high-dose RT alone may be sufficient treatment in men with 2 or more cardiometabolic comorbidities and unfavorable-intermediate- and high-risk PC.

International journal of radiation oncology, biology, physics. 2016 Mar 11 [Epub ahead of print]

Mai Anh Huynh, Ming-Hui Chen, Jing Wu, Michelle H Braccioforte, Brian J Moran, Anthony V D'Amico

Harvard Radiation Oncology Program, Brigham and Women's Hospital, Boston, Massachusetts. Electronic address: ., Department of Statistics, University of Connecticut, Storrs, Connecticut., Department of Statistics, University of Connecticut, Storrs, Connecticut., Prostate Cancer Foundation of Chicago, Westmont, Illinois., Prostate Cancer Foundation of Chicago, Westmont, Illinois., Department of Radiation Oncology, Brigham and Women's Hospital-Dana-Farber Cancer Institute, Boston, Massachusetts.