Abstract
e21570 Background: Primary penile melanoma (PPM) is an exceedingly rare variant of skin cancer, estimated to account for less than 0.18% of all melanomas. As the incidence of melanoma is projected to increase, it is crucial to further understand subtypes of melanoma like PPM. We sought to use the National Cancer Database (NCDB) to describe the epidemiology, clinical features, and treatment modalities of PPM. Methods: We conducted a retrospective review of adults diagnosed with malignant PPM between 2004 and 2021 using the NCDB. Demographic factors analyzed included age, year of diagnosis, insurance status, and facility type. Clinical features studied included regional lymph node examination and treatments. SPSS was utilized to calculate descriptive statistics and chi-square tests for differences between categorical variables. Results: A total of 137 patients met inclusion criteria. The median age at diagnosis was 73 years. The majority of patients were insured by Medicare (n = 86, 63%) or private insurance (n = 46, 34%). About 50% (n = 69) of patients received care at an academic institution with other popular care centers being comprehensive community cancer centers (n = 33, 24%) and integrated network cancer programs (n = 28, 20%). Of the 91 (66%) patients examined for regional lymph node metastasis, 46% (n = 42/91) tested positive. The treatments of choice were partial amputation (n = 70, 51%), excisional biopsy (n = 30, 22%), total amputation (n = 15, 11%), and local excision (n = 10, 7%). After surgical intervention, 74% of patients (n = 101) showed no residual margins. Immunotherapy treatment, which was typically used as an adjuvant (n = 21,15%), increased from 7% (n = 5) of 68 cases diagnosed between 2004 and 2012 to 32% (n = 22) of 69 cases diagnosed between 2013 and 2021 (p < 0.001). Only 7% (n = 9) of patients underwent chemotherapy. Conclusions: To our knowledge, we present the largest study of PPM. Most patients were of older age, covered by Medicare, and examined for regional lymph node metastasis. In line with existing literature that demonstrates increased adoption of organ-sparing procedures over more aggressive approaches for PPM, partial amputation and excisional biopsy were the most common treatments. We observed a rise in the utilization of immunotherapy in the last decade, which is consistent with the timeline of FDA approval of several immune-based therapies for advanced melanoma. Current literature regarding immunotherapy in penile melanoma is scarce. Further research should investigate patient survival and the impact of different treatment modalities on outcomes.