Real-world data on the clinical impact of molecular tumor boards in high- and low-grade serous ovarian cancer.

Background: The clinical impact of molecular tumor boards (MTBs) in epithelial ovarian cancer remains insufficiently characterized, particularly with regard to rare histologic subtypes. We evaluated the real-world implementation and therapeutic relevance of MTB recommendations in high-grade (HGSOC) and low-grade serous ovarian cancer (LGSOC). Methods: We retrospectively analyzed 69 patients with HGSOC or LGSOC who underwent comprehensive molecular profiling and were presented at the interdisciplinary MTB of the University Hospital LMU Munich between November 2017 and June 2023. Molecular alterations, actionability, MTB recommendations, and clinical implementation were assessed. Results: At least one molecular alteration was detected in 50/69 patients (0.71). Actionable alterations were identified in 8/69 cases (0.12), including 4/58 HGSOC (0.07) and 4/11 LGSOC patients (0.36). MTB recommendations resulted in targeted treatment suggestions in eight patients. In three patients, treatment recommendations were clinically implemented, with a median treatment duration of 246 days (range 72-254). Non-implementation was primarily attributable to rapid clinical deterioration. LGSOC patients showed a markedly higher proportion of actionable alterations and MTB-driven therapeutic options compared with HGSOC. Conclusion: In this real-world cohort, actionable mutations in serous ovarian cancer were infrequent, particularly in HGSOC. Clinical benefit was limited by molecular targetability but also by timing and patient deterioration in late-line settings. Our findings suggest that MTB referral may be most valuable in the recurrent/refractory setting for HGSOC, whereas earlier molecular testing, potentially at first relapse, could be considered in LGSOC.