34466 Invasive melanoma among Veterans: A comparative analysis with the SEER registry, 2009-2017

Abstract

Veterans constitute a high-risk population for melanoma, but they are often underrepresented in national registries. We examined differences in melanoma patient and tumor characteristics and melanoma-specific survival between Surveillance, Epidemiology, and End Results (SEER) registry patients and patients in the Veteran Affairs Central Cancer Registry (VACCR). Data were collected from SEER (18 registries) and the VACCR from 2009 to 2017. A total of 15,334 VA enrollees were diagnosed with a primary invasive melanoma vs. 166,265 SEER registry patients. VA enrollees were more frequently greater than 65 years at diagnosis and male compared with their SEER counterparts. VA enrollees were more likely to present with regional or distant disease (17.5% vs. 13.0% in SEER) and more likely to present with tumors greater than 2.00 mm in thickness (20.6% vs. 14.5% in SEER). Comparing melanoma-specific survival, 2-year survival for stage IV melanomas improved from 37.8% in 2011-2014 to 51.5% in 2015-2017. Survival also improved in SEER during these timeframes from 36.4% to 44.8%, respectively. We found that Veterans more commonly present with thicker tumors at more advanced stages than the general population. However, it appears that Veterans with metastatic melanoma are likely benefitting from novel therapies such as PD-1 inhibitors, with a greater increase in survival for stage IV melanomas diagnosed in recent years. Further research is needed to determine if this survival benefit is attributable to novel therapies or if other factors contributed.