Epidemiologic factors and survival outcomes of patients with metastatic malignant melanoma.

e21510 Background: Malignant melanoma has become one of the most common malignancies, with high survival rates if treated early. Recent studies have shown an increase in the incidence of melanoma, particularly in older white males in the United States. There are few recent studies looking at rates of overall survival (OS) of metastatic melanoma based on patient’s demographic factors or metastatic sites. Methods: The Surveillance Epidemiology and End Results (SEER) database was used to identify patients diagnosed with malignant melanoma from 2010-2021. Inclusion criteria were diagnosis of superficial spreading, nodular, or malignant melanoma, not otherwise specified (NOS) in patients with only one primary tumor. Pairwise Chi-square tests were used to identify relationships between race, gender and metastatic disease. Kaplan-Meyer curves were used to identify differences in OS. Results: We identified 10,553 patients, 6,166 male and 4,387 female, of which 3,300 had metastatic disease. The median OS (mOS) of the population was 132 months. Females had higher mOS than males (p < 0.001). White and American Indian or Alaskan Native patients had higher mOS than Black, Hispanic, or Asian and Pacific Islanders (p <0.001). The mOS of patients with metastases was 5 months. More males were diagnosed with metastases than females (2,252 vs 1,048, respectively; p < 0.0001). Black, Hispanic, and Asian or Pacific Islander patients had higher incidence of metastatic disease than White patients (p = 0.0008, p = 4.0e-07, p = 0.01). In patients with one metastatic site (n = 1,090), lung was the most common (n = 977) followed by brain (n = 59), liver (n = 30), and bone (n = 24). Patients with metastases only to the lung (mOS = 17 months) had a higher mOS compared to those with only bone (mOS = 11 months), only brain (mOS = 4 months) or only liver metastases (mOS = 1 months) (p = < 0.0001). In patients with two sites of metastases, one including lung, those with lung and liver metastases had a significantly lower mOS than those with or lung and brain or lung and bone metastases (p < 0.0001). There was no statistically significant difference in OS for patients who had three or more metastatic sites, regardless of combination. Conclusions: Metastatic disease in malignant melanoma is more commonly present in males. Compared to White patients, Black, Hispanic, and Asian or Pacific Islander patients have higher incidence of metastatic disease. The most common site of metastases is the lung, with lung metastases having the highest mOS. Patients with metastatic disease to the lung and brain or bone had higher mOS than those with disease to the lung and liver. Metastases to three or more sites had lower mOS regardless of combination. Further research regarding oligometastatic disease is warranted to study factors impacting survival in this population.