Prognostic features and clinical panthological factors of acral malignant melanoma.

e21591 Background: Extremity-type malignant melanoma (EMM) can occur at the ends of fingers/toes, under nails, and other extremity sites. This study explores the relationship between clinicopathological features and prognosis in patients with EMM to inform clinical decision-making and treatment strategies. Methods: We retrospectively collected clinicopathological data from 201 patients with EMM treated at the Fourth Hospital of Hebei Medical University between January 1, 2013, and June 30, 2024. Variables included gender, age, metastasis, lymph node involvement, surgery, preoperative and postoperative treatments, tumor stage, and genetic testing. Statistical analysis was performed using SPSS 27.0, with survival curves generated by Kaplan-Meier and multivariate analysis using Cox regression. Results: Among 268 patients, 201 with complete data were included. As of July 15, 2024, 80 (39.8%) patients had died, and 121 (60.2%) were alive. The cohort included 108 males (53.7%) and 93 females (46.3%). Metastasis occurred in 12 (6.0%) patients, with common sites being lung (3.0%), liver (0.5%), brain (1.0%), and bone (2.0%). Forty-seven patients (23.4%) had baseline lymph node metastasis, and 91.0% underwent surgery, with 33.9% receiving postoperative adjuvant therapy. Genetic testing in 33 patients revealed mutations in BRAF (1.0%), NRAS (4.0%), KIT (0.5%), and CTNNB1 (0.5%). Survival analysis showed a median overall survival (OS) of 42.3 months, with 1-year, 3-year, 5-year, and 10-year survival rates of 77%, 49%, 36%, and 27%, respectively.Univariate analysis identified baseline lymph node metastasis (HR 0.44, P = 0.001), lack of surgery at initial diagnosis (HR 0.30, P < 0.001), and advanced tumor staging (HR 0.99, P = 0.024) as significant factors for worse OS. Baseline organ metastasis showed a trend towards poorer OS (HR 0.43, P = 0.069). Gender, age, and postoperative adjuvant therapy were not significantly associated with OS. Multivariate analysis revealed that surgery (HR 0.37, P = 0.026) was an independent prognostic factor for OS, and lymph node metastasis showed a statistically significant trend towards worse OS (HR 0.58, P = 0.061). Conclusions: The 5-year survival rate for EMM was 36%, consistent with prior research. Survival analysis identified surgery as a key independent prognostic factor for OS, with baseline lymph node metastasis showing a trend towards worse OS. These findings underscore the importan.