Barriers and drivers of treatment intensification in metastatic castration-sensitive prostate cancer

Importance: Despite evidence of clinical benefits and guidelines recommending first-line treatment intensification for metastatic castration-sensitive prostate cancer, the majority of patients do not receive it. Objective: The goal of IMPLEMENT was to investigate why first-line treatment intensification is underutilized. Design: IMPLEMENT was conducted from March 2022–August 2024. The study comprised three phases and used a mixed-methods approach. Setting: United States Participants: United States-based urologists and oncologists who were primary treaters for ≥1 patient with metastatic castration-sensitive prostate cancer in the past 6 months, had been practicing for 2–35 years, spent ≥50% of their time in direct patient care, and were able to provide informed consent. Recruited using purposive sampling. Interventions: Phase 1: semi-structured interviews based on the Theoretical Domains Framework. Thematic analysis was used to identify barriers and facilitators to treatment intensification. Phase 2: discrete choice experiment to identify priority barriers and helpful resources. Phase 3: co-creation sessions to ideate potential solutions to underutilization based on the findings of the previous phases. Main Outcomes and Measures: Phase 1: barriers to and facilitators of first-line treatment intensification. Phase 2: perceived helpfulness of potential resources for first-line treatment intensification decisions. Phase 3: potential solutions co-created by urologists and oncologists to increase treatment intensification uptake. Results: Phases 1–3 of IMPLEMENT included 36, 302, and 14 participants, respectively. In each phase, half of participants were oncologists and half were urologists. In phase 1, five domains had the greatest influence on intensification: Memory, Attention, and Decision Processes; Environmental Context and Resources; Knowledge; Beliefs About Consequences; and Social/Professional Role. Urologists more commonly reported barriers to intensification, while oncologists more commonly reported facilitators. In phase 2, urologists found decision-support tools most helpful, while oncologists preferred post-treatment databases and clinical trial summaries. In phase 3, cross-specialty tumor boards were ranked by both specialties as the best solution to address treatment intensification underutilization. Conclusions and Relevance: In this qualitative study, the issues underlying treatment intensification underutilization were numerous and multifactorial. The results of IMPLEMENT suggested that the barriers encountered by physicians, and the resources that could help to address them, varied by specialty. All these findings offer insights into physician-supported strategies that could help improve rates of first-line treatment intensification for mCSPC.