Abstract
PURPOSE: Men 80 and over are not well represented on randomized clinical trials, including the studies that examined the addition of androgen deprivation (ADT) to radiation therapy (RT). However, octogenarians may be a group particularly susceptible to the side effects of ADT due to the rapid increase in age-related changes as one enters their 9th decade. We hypothesized that ADT, when added to RT in octogenarians with intermediate-risk prostate cancer, might be associated with worse overall survival, and that this effect would not hold for their younger counterparts. METHODS AND MATERIALS: The National Cancer Database (NCDB) was queried for men ≥60 years old who received dose-escalated RT (EQD2(α/β=2) ≥ 74 Gy) for intermediate-risk prostate cancer. Intermediate risk was defined as prostate specific antigen (PSA) > 10 and ≤ 20, Gleason score 7 (either 3+4 or 4+3), or T2 disease. Men were separated by age (60-69, 70-79, ≥80) and receipt of ADT. Overall survival was evaluated using Kaplan-Meier analysis. Cox proportional hazards were used to determine the relationship between ADT usage on survival in different age cohorts. RESULTS: There were 10,168 men who received RT + ADT versus 12,396 who received RT alone. In the RT + ADT group, a larger percentage of men had Gleason 4+3 disease (43% vs 26%, P = .004), T2 stage (35% vs 25%, P = .019), and a higher PSA (median 7.6 vs 6.8, P < .0001). There were 672 (6.6%) octogenarians who received ADT versus 772 (6.2%) who did not. Hazard ratios (HRs) for overall survival, accounting for Gleason score, T stage, PSA, and comorbid conditions, showed improved survival in those 60 to 69 with the addition of ADT to dose-escalated RT (HR = 0.90 [95% CI, 0.81-0.99], P = .039), while no difference in those 70-79 (HR = 0.98 [0.90-1.06], P = .541) or 80 and older (HR = 1.13 [0.97-1.32], P = .124). CONCLUSIONS: In this NCDB analysis, the addition of ADT to dose-escalated radiation in men between the ages of 60 and 70 with intermediate-risk prostate cancer showed improved overall survival. However, adding ADT to dose escalation in those 80 and older did not demonstrate an overall survival benefit.