Clinicopathological predictors of survival and disease progression in melanoma: A real-world cohort from the MENA region.

Abstract

e21601 Background: Melanoma exhibits marked heterogeneity in clinical behavior, with survival outcomes strongly influenced by primary tumor biology. While established histopathological features are known to predict prognosis, real-world data from the Middle East and North Africa (MENA) region remain limited. Methods: We conducted a retrospective cohort study using electronic health record data from the American University of Beirut Medical Center, including adult patients diagnosed with melanoma between January 1, 2014 and August 1, 2024. The study aimed to identify clinicopathologic predictors of survival and disease progression in a real-world melanoma cohort. Overall survival (OS), progression-free survival (PFS), and recurrence-free survival (RFS) were estimated using Kaplan-Meier methods and compared using the log-rank test. Univariable and multivariable Cox proportional hazards models were used to identify independent predictors of mortality and disease progression. Results: The overall 5-year survival rate for the cohort was 82.8%, though outcomes were heavily influenced by primary tumor biology. Univariable Cox regression identified mitotic activity as the most potent predictor of mortality, where a count of ≥7 mitoses carried a hazard ratio (HR) of 4.11 (95% CI: 2.12-7.95, p < 0.001) compared to tumors with no mitoses. In the adjusted multivariable model, Breslow thickness category remained the sole independent predictor of death (adjusted HR 1.72 per category increase, 95% CI: 1.09-2.71, p = 0.020), confirming that the vertical depth of the primary lesion is the most reliable independent indicator of long-term mortality risk. PFS was significantly superior in early-stage patients compared to those with advanced disease (log-rank p = 0.020), with median PFS for the advanced group limited to 44.0 months. Multivariable analysis for PFS identified the Clark Level of invasion as a critical independent risk factor (adjusted HR 1.82, 95% CI: 1.07-3.08, p = 0.026), indicating that the anatomical layer of skin reached by the tumor significantly dictates the speed of disease advancement. Similarly, RFS was strongly influenced by stage, where advanced-stage patients faced a significantly higher risk of relapse (log-rank p = 0.003), driven primarily by the interrelated factors of tumor thickness and high mitotic counts. Conclusions: In this real-world cohort from the MENA region, primary tumor biology was the main determinant of long-term outcomes in melanoma. After multivariable adjustment, Breslow thickness remained the sole independent predictor of death, while measures of anatomic invasion independently predicted disease progression and recurrence. These findings highlight the continued prognostic value of classical histopathological features in routine clinical practice.