Barriers to and facilitators of first-line treatment intensification (TI) in metastatic castration-sensitive prostate cancer (mCSPC) by practice setting and intensification frequency: A sub-analysis of IMPLEMENT.

48 Background: First-line TI (i.e., androgen-deprivation therapy + chemotherapy, androgen receptor pathway inhibitors, or both) is recommended for mCSPC but is underutilized. Phase 1 of IMPLEMENT identified barriers to and facilitators of TI. Phase 2 prioritized these factors and identified resources to increase TI. This sub-analysis describes the results in academic and nonacademic settings, and among high and low intensifiers (physicians who use first-line TI in >50% vs ≤50% of patients, respectively). Methods: Phase 1: Semi-structured virtual interviews with 18 oncologists and 18 urologists, using an implementation science approach based on the Theoretical Domains Framework to analyze themes by setting and intensification frequency. Phase 2: Discrete choice experiment with 302 physicians who reviewed descriptions of potential resources across 12 scenarios and selected the most helpful for increasing TI. We used a mixed-effects logistic regression model to calculate a coefficient of helpfulness for each resource to identify those with the strongest impact on TI decisions. Results: Phase 1:Low intensifiers and nonacademic physicians more frequently reported barriers to TI. Low intensifiers had gaps in clinical trial knowledge, tended to reserve TI for later, and had low-intensifier peers; nonacademic physicians had concerns about side effects, cost, and impact on quality of life. High intensifiers and academic physicians more frequently reported facilitators such as good clinical support and anticipated regret about missing the best chance at improving survival. Phase 2: Significant differences were noted between high and low intensifiers in the utility of decision support and clinical trial summaries (Table). Conclusions: Decision support tools and databases of post-treatment options may help address barriers to TI and improve guideline-concordant care. Resource, mean COH (±SD) Academicn = 81 Nonacademicn = 221 High intensifiersn = 184 Low intensifiersn = 118 Database of post-treatment options 1.89(0.38) 1.80(0.38) 1.94(0.39) 1.65(0.36) Decision support tool linking patient characteristics to first-line treatment options 1.60(0.53) 1.75(0.53) 1.45*(0.52) 2.12*(0.51) Summaries of key clinical trial data 1.39(0.40) 1.25(0.44) 1.55*(0.44) 0.88*(0.37) Cross-specialty treatment guidelines 0.57(0.26) 0.59(0.25) 0.48(0.22) 0.75(0.30) Information comparing clinical outcomes of first-line vs later TI 0.41(0.21) 0.37(0.18) 0.40(0.19) 0.36(0.19) Tools to reduce administrative burden 0.13(0.06) 0.23(0.11) 0.18(0.10) 0.25(0.11) COH, coefficient of helpfulness (scaled to have average value of 1, i.e., >1: above average utility; <1: below average utility). * P < 0.05 from bootstrap testing of subgroup averages.