Abstract
e21565 Background: Malignant blue nevus (MBN) is a rare and aggressive melanoma that arises in a blue nevus and tends to metastasize to the lymph nodes. Metastasis has been described in up to 55% of cases, and the 10-year survival rate is 51%. Current literature on MBN is limited. Data from the National Cancer Database (NCDB) on the demographic and socioeconomic characteristics of patients with MBN could provide insightful information regarding the epidemiology of this rare disease. Methods: The 2004-2020 NCDB was used to perform a retrospective cohort analysis of patients diagnosed with malignant blue nevus (N = 118) using ICD-O-3 code 8780/3. This study used descriptive statistics to analyze factors such as age, sex, income status, insurance status, Charlson-Deyo score, treatments, and survival rates. Results: A total of 118 patients diagnosed with MBN were recorded in the NCDB with an average age at diagnosis of 56.7 ± 17.2 years with a female preponderance (59%). Nearly all patients were insured (99%), mostly by private insurance (59%) or Medicare (27%). Over half of patients (54%) were enrolled in research programs, and 62% of patients comprised the top two income quartiles based on median household income. The vast majority of patients (81%) had no major comorbidities (Charlson-Deyo = 0). The top primary sites were the skin of the scalp and neck (36%) and the trunk (21%). The average tumor size was 21.2 ± 30.3 mm ranging from 2 mm-120 mm. The most frequent treatment performed was surgery, with 92% of patients undergoing surgical procedures of the primary site. Among these, the most common procedures were wide excision or re-excision (52%), excisional biopsy (14%), and shave biopsy followed by gross excision (10%). After resection, 77% of patients showed no residual tumor. In place of surgery, a smaller number of patients received alternate treatments as their main therapy, such as radiation therapy (11%), chemotherapy (6%), or immunotherapy (12%). The 2-year and 5-year survival rates were 88% and 68% respectively. Conclusions: Based on our literature review, this study is the first NCDB analysis on MBN and presents data from the largest cohort of patients to date. Patients with MBN are more likely to be female, and most lack major comorbidities. The most common sites are the scalp, neck, or trunk, in line with current literature. Review of socioeconomic factors revealed that an overwhelming majority of patients are likely to be insured and in the top two income quartiles. These findings could implicate that those who are more socioeconomically advantaged may have more resources for recognition of disease and proper diagnosis, especially considering the challenges of diagnosing MBN due to poorly defined histological criteria. Further research efforts should investigate the impacts of socioeconomic factors on diagnosis, treatments, and prognosis.