Androgen-deprivation therapy (ADT) in combination with radiotherapy (RT) is associated with better cancer-specific and overall survival compared with ADT alone in older men with locally advanced or screen-detected high-risk prostate cancer, according to a new study.
Using the Surveillance Epidemiology and End Results (SEER)-Medicare database, Justin E. Bekelman, MD, of the University of Pennsylvania in Philadelphia, and colleagues identified 3 groups of older men with locally advanced or high-risk prostate cancer (PCa) diagnosed from 1995 to 2007 and observed through 2009. These groups included a randomized clinical trial (RCT) cohort of 4,642 men aged 65–75 years; an elderly cohort of 8,694 men older than 75 years with locally advanced PCa; and a cohort of 2,017 men aged 65 years and older with screen-detected high-risk PCa.
ADT plus RT was used in 64.1% of the RCT cohort, 52.8% of the screen-detected cohort, and 39.4% of the elderly cohort.
In the RCT cohort, ADT plus RT was associated with a 57% decreased risk of cancer-specific mortality and a 37% decreased risk of all-cause mortality compared with ADT alone in propensity score-adjusted analyses, Dr. Bekelman’s team reported online ahead of print in the Journal of Clinical Oncology. In the elderly cohort, ADT plus RT was associated with a 49% and 37% decreased risk of cancer-specific and all-cause mortality, respectively. In the screen-detected cohort, ADT plus RT was associated with a 75% and 50% decreased risk of cancer-specific and all-cause mortality, respectively.
The researchers commented that their findings “raise a provocative hypothesis” that in the United States, men older than 75 years with locally advanced PCa or men older than 65 years with high-risk screen-detected PCa who receive ADT alone are at risk for decrements in cancer-specific and overall survival.
Dr. Bekelman’s group observed that their results are consistent with and extend the findings of previous studies looking at the role of ADT and RT in the management of older men with locally advanced or high-risk PCa. One such study is the Scandinavian Prostate Cancer Group Study 7, in which investigators randomly assigned 875 men with locally advanced or high-risk localized PCa and a mean age of 66 years to receive ADT alone or ADT plus RT. Results showed that ADT plus RT was associated with a large and significant reduction in cancer-specific and all-cause mortality, according to a report published in The Lancet (2009;373:301–308).
In an editorial accompanying the report by Dr. Bekelman and colleagues, Dean A. Shumway, MD, and Daniel A. Hamstra, MD, of the University of Michigan in Ann Arbor, commented that the study “contributes significantly to our understanding of both the age-dependent bias against treatment as well as the benefits of RT added to ADT in elderly men with locally advanced or screen-detected high-risk prostate cancer.”