Surrogate End Points for All-Cause Mortality in Men With Localized Unfavorable-Risk Prostate Cancer Treated With Radiation Ther

Several surrogates for prostate cancer-specific mortality satisfying the Prentice criteria exist, but whether these are surrogates for all-cause mortality, and how their performance compares, is unknown. To ascertain and compare the performance of 4 candidate surrogates (prostatespecific antigen [PSA] failure, PSA nadir >0.5 ng/mL, PSA doubling time <9 months, and interval to PSA failure <30 months) for all-cause mortality using the proportion of treatmenteffect metric. For this randomized clinical trial, 206 men with unfavorable-risk prostate cancer who were seen at a Harvard-affiliated academic hospital or an associated community hospital between December 1, 1995, to April 15, 2001, were identified, randomized to radiation therapy alone or radiation therapy followed by 6 months of androgen deprivation therapy, and followed for a median 16.62 years. This analysis looks at the subgroup of 157 men with minimal comorbidities or no comorbidity (median follow-up, 16.49 months). Patients were previously randomized to receive radiation therapy or radiation and 6 months of androgen deprivation therapy. Risk of all-cause mortality. Overall, a cohort of 157 men (median [interquartile range] age, 72.43 [68.75-75.53]) with unfavorable-risk prostate cancer and minimal or no comorbidities were selected for this study. Three tested metrics met all 4 Prentice criteria for surrogacy for the surrogate covariate in the adjusted model for all-cause mortality: PSA nadir greater than 0.5 ng/mL (adjusted hazard ratio [aHR], 1.72; 95% CI, 1.17-2.52; P = .01), PSA doubling time less than 9 months (aHR, 2.06; 95% CI, 1.29-3.28; P = .003), and interval to PSA failure less than 30 months (aHR, 1.76; 95% CI, 1.06-2.92; P = .03); while PSA failure did not. For the 3 successful surrogates, the proportion of treatment effect values were 103.86%, 43.09%, and 41.26%, Format: Abstract 1 2 2 3 4 5 3 Author information Full text links Surrogate End Points for All-Cause Mortality in Men With Localized ... https://www.ncbi.nlm.nih.gov/pubmed/28097317 1 di 2 16/09/2017, 04.51 CONCLUSIONS AND RELEVANCE: