Population-based Assessment of Intermittent Androgen Deprivation Therapy Utilization for Relapsed, Nonmetastatic, Hormone-sensitive Adenocarcinoma of the Prostate.

OBJECTIVES: Androgen deprivation therapy (ADT) is the standard of care for men with nonmetastatic hormone-sensitive prostate cancer (nmHSPC) after treatment failure. Although intermittent ADT (iADT) is noninferior to continuous ADT for prostate cancer outcomes, with superior quality of life and cost-to-benefit ratio, little is known regarding its real-world utilization. The authors aimed to determine the utilization of iADT in a Canadian Provincial Cancer Program for relapsed nmHSPC and identified risk factors associated with the nonreceipt of iADT. MATERIALS AND METHODS: This retrospective population-based cohort study used linked administrative databases to identify all patients with relapsed nmHSPC from 2012 to 2016 and quantified ADT prescription history. Patients were defined as iADT eligible if prostate-specific antigen (PSA) was <4 ng/mL and trending downwards on ≥2 sequential PSAs after ≥6 months of ADT. Univariable and multivariable logistic regression analyses were performed to determine factors associated with nonreceipt of iADT. RESULTS: A total of 601 men with relapsed, nmHSPC were included with a median age at relapse of 73 (range, 46 to 96), pre-ADT PSA of 12.2 ng/mL, and a median pre-ADT PSA doubling time of 7.8 months. 80.9% of the cohort were eligible to receive iADT and 74.4% were treated with iADT. On multivariable analysis, patients originally treated with surgery (odds ratio [OR], 0.19; 95% confidence interval [CI], 0.08-0.46) or having a Gleason Score ≥8 (OR, 0.30; 95% CI, 0.12-0.78) had decreased odds of receipt of iADT. Patients with longer PSA doubling times were more likely to receive iADT (OR, 2.71; 95% CI, 1.17-6.31). CONCLUSIONS: The utilization of iADT was relatively common for men in Manitoba during the study period, however, the uptake of iADT can be improved among identified subgroups.