Adherence to standard of care (SOC) therapy for the treatment of metastatic hormonesensitive prostate cancer (mHSPC): A single-institution analysis.

103 Background: Androgen deprivation therapy (ADT) has been the backbone of treatment for mHSPC for decades. In recent years, multiple randomized controlled trials demonstrating an overall survival (OS) benefit of combination treatment (e.g. ADT + novel hormonal agent and/or chemotherapy) has made this the current SOC. Large real-world reports have shown a significant number of patients are still being treated below the SOC with ADT alone, but these databases do not include patient level data to help understand the rationale for treatment decisions. We reviewed our institution’s treatment patterns for mHSPC to better understand why some patients are being treated with ADT alone. Methods: We conducted a retrospective analysis on patients who initiated treatment for mHSPC from 2017-2021 at Cleveland Clinic. Patient characteristics were recorded, including age and histology. Treatment characteristics, including location of treatment, treatment regimen, and treatment rationale (if not treated with SOC) were noted. Results: Four hundred forty-nine patients were included, with diagnosis of metastatic disease made at a median of 63 years, of which 446 started treatment with systemic therapy. The vast majority of patients were managed by a medical oncologist (95.5%). About half of the patients (49.8%) received treatment at the main campus, with the remaining patients being treated at an affiliated regional hospital (28.7%) or outpatient medical center (21.5%). Additional characteristics are shown. Out of the 446, 40 (9.0%) patients received ADT alone. Reasons for ADT monotherapy included patient preference (n = 13), cost (n = 2), and poor functional status/comorbidities (n = 4). Twenty (50%) of the patients who got ADT alone had no documented rationale for why this treatment plan was elected. One patient was lost to follow-up. For patients who received only ADT, 12 were treated at main campus, 20 were treated at a regional hospital, and 8 were treated at an outpatient medical center. Conclusions: At our institution, adherence to treatment up to SOC for mHSPC was better than previous real-world reports. There were documented reasons for not treating mHSPC up to SOC combination therapy for half of the patients who got ADT monotherapy. It remains unclear why the remaining half did not get combination therapy up to the SOC. [Table: see text]