NCTQ-06 PREVALENCE OF MELANOMA BRAIN METASTASES AND PATIENT SURVIVAL OUTCOMES: A POPULATION-BASED STUDY FROM 2014-2024

Abstract Melanoma is the fifth most common cancer diagnosis in the United States and third leading cause of brain metastases (BM). Prior population-based studies reflect only synchronous melanoma BM, and analyses including precocious and metachronous BM may better inform clinical management. Thus, we retrospectively analyzed the prevalence and survival patterns of patients with melanoma BM in the TriNetX Oncology dataset. Data were extracted from 17,466 patients with histologically-confirmed melanoma. Chi-squared and t-test analyses compared demographic and clinical parameters. Kaplan-Meier and Cox regression analyses assessed BM-free and overall survival after propensity matching for age, sex, race, ethnicity, skin lesion excision, stage, extracranial metastases, radiation, and antineoplastic treatment (p<0.0001 for all). Overall, the prevalence of BM in melanoma was 6.9%. Precocious, synchronous, and metachronous BM accounted for 7.4%, 21.9%, and 70.8% of cases, respectively. BM development was associated with male sex, White race, non-Hispanic ethnicity, historical tobacco use, familial cancer history, and extracranial metastases (p<0.0001 for all). The probability of BM-free survival during follow-up was 97.3%, 87.3%, 80.3%, and 59.1% in initial stage 1, 2, 3, and 4 melanoma, respectively, while one-year BM-free survival was 99.9%, 99.3%, 97.4%, and 69.3%. After propensity matching, the median BM-free survival was 32.9 months for stage 4 melanoma but not reached for stage 1-3 melanoma. Regarding overall survival analyses with propensity matching, individuals with BM had a median survival of 45.4 months after melanoma diagnosis, which was reduced relative to patients without BM (not reached; HR [95%CI]: 2.253 (1.957, 2.595), p<0.0001). When assessed from metastasis diagnosis, patients with BM exhibited reduced median overall survival compared to patients with extracranial metastases only (13.5 vs. 123.8 months; HR [95%CI]: 2.754 (2.399, 3.161), p<0.0001). In conclusion, our analyses highlight the chronicity and impact of BM on survival outcomes in melanoma. These findings may inform surveillance and treatment guideline refinement.