NCTQ-07 Impact of Sex on Brain Metastasis Prevalence and Survival Outcomes in Melanoma: A Retrospective Analysis of the Trinetx Oncology Database

Melanoma is the third most common cause of brain metastases (BM). While sex-based survival differences in melanoma are well-established, the impact of sex on BM prevalence and survival outcomes is less studied. Moreover, current population-based studies reflect only synchronous BM. This retrospective analysis of melanoma patients from 2014-2024 in the TriNetX Oncology database examined sex in BM prevalence and survival. Demographic and clinical characteristics were evaluated using chi-squared and t-test analyses. BM-free and overall survival were assessed using Kaplan-Meier and Cox regression analyses after propensity matching for age, race, ethnicity, stage, extracranial metastases, skin lesion excision, antineoplastic treatment, and radiation. Our cohort included 9,956 male and 7,614 female patients with histologically-confirmed melanoma. The overall BM prevalence was 6.6%. BM development was associated with male sex (p<0.0001), White race (p=0.0078), non-Hispanic or Latino ethnicity (p<0.0001), and an initial stage 3 or 4 melanoma diagnosis (p<0.0001). After propensity matching, males had a higher probability of developing BM (7.1% vs. 5.0%; HR [95%CI]: 0.703 (0.615, 0.804, p<0.0001). However, BM-free survival did not differ between males (13.4 months) and females (13.5 months; HR [95%CI]: 0.969 (0.835, 1.124), p=0.6774). Survival analysis with propensity matching for patients with BM demonstrated reduced median overall survival from melanoma diagnosis in males (51.5 months) relative to females (97.1 months; HR [95%CI]: 0.731 (0.582, 0.919), p=0.0069). Additionally, median overall survival from BM diagnosis was lower for males (18.9 months vs. 35.3 months; HR [95%CI]:0.773 (0.612, 0.976), p=0.0298). The one-year survival probability from BM diagnosis was 56.4% for males and 65.9% for females (HR [95%CI]: 0.766 (0.585, 1.001), p=0.0500), whereas the five-year survival probability was 39.8% for males and 50.6% for females (HR [95%CI]: 0.750 (0.593, 0.950), p=0.0164). These findings suggest that sex affects BM likelihood and outcomes in melanoma, warranting further investigation into contributing biological or clinical factors.