Is Time to Biochemical Failure a Surrogate Endpoint in Locally Advanced Prostate Cancer?
Posted: Tuesday, January 29, 2019
The time interval free of biochemical failure may prove to be a surrogate endpoint in clinical trials and also may be of assistance in risk-monitoring after initial treatment with radiotherapy plus long-term androgen-deprivation therapy for locally advanced prostate cancer. An analysis of the NRG/RTOG 9202 trial, by James J. Dignam, PhD, of the Department of the University of Chicago, and colleagues, was published in the Journal of Oncology.
“On the basis of the evidence, the [interval free of biochemical failure] would seem to have a clear role in clinical decision making, informing when more intensive surveillance or treatment is warranted,” the authors concluded.
A total of 762 study patients received radiotherapy plus short-term androgen deprivation (4 months), and 758 patients received long-term androgen deprivation (28 months).
Long-term androgen deprivation was found to be “superior” to short-term androgen deprivation for both biochemical failure and the clinical endpoints. Researchers observed a 39% overall survival risk reduction in men who were free of biochemical failure for 3 years as well as a 73% risk reduction for prostate cancer–specific survival.
“Analysis accounting for 3-year [interval to biochemical failure] status reduced the [long-term androgen deprivation] vs [short-term androgen deprivation] overall survival benefit from 12% (hazard ratio = 0.88) to 6% (HR = 0.94) and the [long-term androgen deprivation] prostate cancer–specific survival benefit from 30% (HR = 0.70) to 6% (HR = 0.94),” the authors reported.
Of the men who had experienced biochemical failure, 50% of the subsequent deaths by 12 years were attributed to prostate cancer, whereas 19% of subsequent deaths attributed to prostate cancer among men who did not have biochemical failure.
Disclosure: The study author’s full disclosures can be found at ascopubs.org.