Effect of demographic characteristics on the outcome of prostate cancer salvage radiotherapy: analysis from a randomized controlled trial

BACKGROUND: This study investigated the impact of advanced molecular imaging, race, socioeconomic status, and metabolic dysregulation on the outcome of salvage radiotherapy (sRT) for prostate cancer recurrence in a clinical trial setting. METHODS: The authors randomized post‐prostatectomy men with detectable prostate‐specific antigen to sRT guided by conventional imaging (arm A) or 18F‐fluciclovine‐positron emission tomography/computed tomography (arm B) and followed them up for up to 48 months to determine failure‐free survival (FFS). The authors computed socioeconomic status (SES) and allostatic load (AL) scores to quantify socioeconomic status and level of metabolic dysregulation. They stratified patients by race as African American men (AAM) versus men of other races (MOR) and compared FFS between them using the z‐test. RESULTS: Eighty‐one (AAM = 29, MOR = 52) and 76 (AAM = 26, MOR = 50) men completed per‐protocol sRT in arms A and B, respectively. Across study arms, AAM showed a higher FFS rate than MOR (72.8% [95% CI, 53.8%‐85.0%] vs. 58.7% [95% CI, 46.6%‐68.9%]; p = .002). In arm A, FFS rate was better for AAM than MOR, (64.0% [95% CI, 34.4%‐82.9%] vs. 45.3% [95% CI, 28.8%‐60.4%]; p = .008). In arm B, FFS improved for both groups but less so for AAM, (81.5% [95% CI, 57.2%‐92.7%] vs. 73.0% [95% CI, 56.3%‐84.1%]; p = .131). The authors found lower SES scores and higher AL scores for AAM in both study arms than MOR. CONCLUSION: Despite lower socioeconomic status and higher burden of metabolic dysregulation, in a clinical trial setting that controls for disparities in health care access, AAM have a more favorable sRT outcome than MOR.