Mucosal melanoma treatment patterns and outcomes in real clinical practice: Single institution experience.

Abstract

e21571 Background: Mucosal melanoma (MM) is a challenging malignancy to diagnose and treat, even with the advent of modern drug therapies. There is a lack of established surgical, radiological, or pharmacological treatment approaches for locally advanced or metastatic mucosal melanoma. This study analyzes the treatment practices and clinical outcomes at a single institution over a five-year period to understand real-world clinical practices. Methods: A сomprehensive, continuous, retrospective study analyzed medical records of adults with histologically confirmed MM at the N.N. Blokhin Russian Cancer Research Center from January 2018 to December 2023. Data was digitized into an electronic questionnaire, with patient follow-up conducted via telephone. Results: A total of 87 patients were identified, comprising 72 females (82.8%) from 31 regions of Russia. The median age was 67.8 years (ranging from 29.5 to 90.1 years). The patient breakdown was as follows: 6 with head&neck MM (6.9%), 41 with vulvovaginal MM (47.1%), 5 with penile MM (5.7%), 27 with anorectal MM (31.0%), and 8 with gastrointestinal MM (9.2%). A significant portion of the patients presented with locally advanced (22.9%) or metastatic disease (67.8%), while 9.2% of the patients had undergone surgery and were being considered for adjuvant treatment. The most common sites of metastasis were regional lymph nodes (23%), liver (14%), and lungs (11.5%), with one patient having CNS metastasis. Mutational status was determined for 48 of the 87 patients, revealing driver mutations in 12 patients (Table). The majority of patients were initially treated with immunotherapy. The most frequently used therapies included monotherapy with anti-PD-1 agents (nivolumab or pembrolizumab, accounting for 41.6%) and a combination of ipilimumab and nivolumab (33.3%). After a median follow-up of 17.7 months, the median overall survival (OS) for the entire cohort was 18.1 months (with a 95% confidence interval ranging from 6.8 to 23.2 months), showing no significant statistical differences in outcomes based on the location of the mucosal melanoma or the type of treatment received. Conclusions: Mucosal melanoma remains an under-researched malignancy. There is a critical need for prospective, randomized trials to explore more effective treatment options for patients with this condition. [Table: see text]