Background: Precision medicine has revolutionized cancer care in advanced NSCLC and new actionable biomarkers and targeted therapies are emerging at an unprecedented pace, creating myriad opportunities to improve care and mitigate the often-dire sequelae of traditional cancer therapy. Delays in uptake of testing and biomarker-guided treatment for patients with NSCLC and EGFR activating mutations or ALK fusions are well documented despite clear evidence-based practice, guidelines, and expert recommendations. In this study, we analyze healthcare professionals (HCPs) awareness and application of RET fusion testing and integration of recently approved selective RET inhibitors into practice for appropriate patients with advanced NSCLC. Methods: From 1/2020-6/2022, multiple educational activities were developed to provide HCPs with evidence-based expert and guideline recommendations on assessment of and therapy selection for RET fusion–positive NSCLC. The activities comprised live symposia associated with 4 major oncology and pathology conferences (AMP, USCAP, ASCO, AACR), 3 regional live workshop series across the US, 3 live webinars, and 2 on-demand videos. Baseline polling questions designed to assess key aspects of HCP knowledge and practice patterns were repeated at each activity. Results: Across all activities at baseline, on average only 38% of responding HCPs correctly identified RNA NGS as the most sensitive testing assay for detection of RET fusions and 36% accurately selected the appropriate targeted therapy for patient case with a KIF5B-RET gene fusion. From 2020 through 2022, with each new group of learners across different scopes of practice, we found suboptimal awareness of optimal RET fusion testing methodology and choice of therapy for patients with RET fusion–positive NSCLC (table). Optimal responses were slightly higher among learners attending conference-associated symposia vs live workshop series and online education. Conclusions: The use of optimal testing assays for RET alterations across patients with NSCLC remains low and many HCPs continue to lack awareness of appropriate targeted therapy for patients with RET–fusion positive NSCLC > 2 years after the first approved indication for this biomarker. These results underscore a lag in adoption of optimal precision medicine approaches for NSCLC among oncology HCPs and the need for expert guidance and educational activities to optimize individualized, biomarker-driven treatment approaches. An analysis of patterns by HCP role (MD, NP/PA, RN, Pharmacist) will be presented.