Clinical characteristics, treatment response, and survival outcomes in melanoma patients with cavity carcinomatosis: A retrospective analysis.

The clinical features, treatment efficacy, and prognostic differences in melanoma patients with cavity carcinomatosis, which is of rare occurrence, are still unclear. A retrospective analysis was conducted on melanoma patients with cavity carcinomatosis treated at Fujian Cancer Hospital from 2007 to 2023, with follow-up ending in March 2024. The results showed that among 1430 melanoma patients, 79 had cavity carcinomatosis (5.5%). Median time to cavity carcinomatosis was 6.53 months (interquartile range: 0.23-26.20). The survival after melanoma cavity carcinomatosis was 5.23 months (95% CI: 4.39-6.07). Post-cavity carcinomatosis survival improved to 6.30 months with treatment, versus 1.13 months without (p = .001). Anti-BRAF treatment did not outperform with only 4.83 months of progression-free survival, and the objective response rate was 14.29%. The curative effect of chemotherapy and immunotherapy on BRAF wild-type patients was similar. LDH levels strongly correlated with cavity carcinomatosis survival; patients with LDH ≤ ULN and ULN < LDH ≤ 2.5ULN lived longer than those with LDH > 2.5ULN (6.77 vs. 5.13 vs. 2.67 months, p = .008). This indicated that melanoma with cavity carcinomatosis should be considered a distinct subtype that signifies a high mortality rate. Continuous anti-tumor therapy can still improve survival despite the lack of standout treatments after onset. Serum LDH levels hold the potential to serve as a crucial survival predictor.