Evaluation of imiquimod treatment outcomes in vulvar melanoma.

5540 Background: Vulvar and vaginal melanomas account for approximately 10% of vulvar malignancies and less than 1% of all melanomas. Compared to cutaneous melanoma at other sites, vulvovaginal melanoma is associated with significantly worse outcomes. Wide local excision is the standard treatment for vulvar melanoma, but anatomical challenges and the “field effect” complicate complete resection. The field effect refers to a margin of pre-cancerous intraepithelial cells extending beyond the visible tumor and is thought to contribute to local recurrence. Imiquimod, an immune-modifying cream indicated for genital warts and some types of early keratinocyte carcinomas, is used off-label as an adjunct therapy to prevent marginal recurrence of vulvar melanoma in situ. Its benefit in this setting remains unclear due to limited outcome data, and it is associated with significant side effects. More research is needed to clarify the role of imiquimod and explore alternative therapies. This case series aims to evaluate recurrence and survival outcomes following imiquimod treatment and inform clinical management in this understudied cancer subtype. Methods: Patients were identified by two criteria: (1) confirmed vulvar melanoma and (2) treatment with imiquimod. Cases were drawn from a previously published institutional cohort focused on adjuvant radiation therapy in vulvovaginal melanoma and from MD Anderson’s electronic medical records. Regional progression-free survival and overall survival were defined as study endpoints. Data included demographics, clinical characteristics, and recurrence and mortality outcomes. Kaplan–Meier analysis compared progression-free and overall survival between patients treated with imiquimod and those who were not. Results: Among 124 patients, 19 received imiquimod. The imiquimod group showed a modest improvement in regional progression-free survival, but no significant difference in overall survival (p = 0.1753 and p = 0.2775, respectively). Imiquimod was associated with notable side effects, including burning, itching, and blistering. Conclusions: This case series highlights the limited evidence supporting imiquimod as an effective adjunct therapy for vulvar melanoma. Although there was a trend toward delayed regional progression, differences were not statistically significant, and side effects raise concerns about patient quality of life. These findings underscore the need for more effective and tolerable strategies. A systematic review is underway, and multi-institutional efforts aim to expand the dataset. Greater evidence is essential to guide treatment decisions, optimize outcomes, and ensure survivor-centered care in this rare and understudied cancer.