Precision medicine and multidisciplinary care in gastric and gastroesophageal junction (G/GEJ) cancers: Challenges and practice gaps in community cancer clinics.

385 Background: The advent of biomarker-driven therapeutic strategies brings increasing precision to the treatment of G/GEJ cancer, placing biomarker testing at the forefront of patient management. The management of evolving logistics for testing and related decision-making can be challenging, especially in community clinics. As part of a multi-center quality improvement initiative, we evaluated current gaps in biomarker testing and practice patterns including multidisciplinary care for G/GEJ cancers in community oncology centers. Methods: Between 5/2024 and 8/2024, oncology team members (N = 60) from 5 US-based community oncology practices completed surveys assessing attitudes, knowledge, competence, practice patterns, challenges, and gaps regarding biomarker testing and multidisciplinary care in G/GEJ cancers. Results: Despite practice guidelines, many patients with G/GEJ cancer did not receive testing for recommended biomarkers. While most providers report that biomarkers HER2 (67%) and PD-L1 (62%) are routinely reported in pathology reports, less than half said testing for MSI/MMR, TMB, and BRAF p.V600E were reported, and less than 25% reported analysis of NTRK1/2/3 , RET , CLDN.18.2, and FGFR2 . Biomarkers most frequently requested if not included in the original pathology work-up were PD-L1 (48%), TMB (32%), and BRAF p.V600E (32%). Top challenges reported by providers in integrating biomarker testing into practice were prioritizing testing for limited tissue (38%), determining whether to begin treatment prior to receipt of molecular testing results (35%), and optimizing specimen collection for molecular testing (27%). Only 23% of providers reported feeling very or extremely comfortable (4/5 on 5-point Likert scale) with interpreting and applying biomarker testing results to treatment decision-making. Additional challenges included turnaround time for biomarker testing, uncertainty interpreting biomarker results, and inconsistent or infrequent multidisciplinary tumor boards. Indeed, some providers (12%) reported not participating in multidisciplinary tumor boards at all, while others reported participating weekly (16%), once or twice a month (21%), every other month (12%), or less frequently (23%). Providers believed improving test ordering process (47%), decreasing testing turnaround time (42%), and standardizing panels for biomarker testing (40%) would be most impactful in implementation of biomarker testing into clinical workflows. Conclusions: Although most oncology teams reported use of some form of biomarker testing in treatment of G/GEJ cancer, testing was inconsistent and not as comprehensive as currently recommended. These data will be leveraged to develop multidisciplinary action plans with participating clinics to improve biomarker testing for treatment selection in G/GEJ cancers.