Long-term time trends in incidence, survival, and mortality of malignant melanoma in the United States.

Abstract

e21599 Background: While there have been newer treatments that were developed in the last decade for metastatic melanoma, there is lack of data that directly looks at survival in melanoma before and after introduction of these new agents. We tried to explore the epidemiology of malignant melanoma including incidence to look at the trends of its incidence, survival and mortality in different groups over the last two decades. Methods: Data was obtained from the Surveillance, Epidemiology, and End Results Program (SEER Research Data, 18 Registries from 2000-2018) and data was cleaned and analyzed in STATA 16. 363,517 records were included in analysis from which baseline characteristics and median were obtained for survival time and survival analysis was done by Cox regression method to compare survival time between different groups. Pearson correlation was calculated to look for association between survival time and Breslow thickness. Results: Mean age group was 55-64 years, with 58% males and 42% females. 95% were White, 0.43% were Black, 0.63% were Asian and 3.79% were other races. 87% were localized, whereas 13% were metastatic. Mean Breslow thickness was 1.27mm (1.26-1.28). Overall median survival time was 62 months for malignant melanoma and 27 months for metastatic malignant melanoma. 42.63% were diagnosed before 2009 and 57.37% were diagnosed from 2009 to 2018. Cumulative incidence rate of melanoma increased from 4.78 to 6.57 per 100,000 persons whereas mortality rate increased from 0.29 to 2.23 per 100,000 persons from years 2000 to 2012 respectively. With contrast to age below 65, patients with age 65 and above had lower survival time (HR 4.78 95% CI 4.71-4.85, p < 0.01). There seemed to be an increase in incidence of melanoma among patients above 65 compared to below 65. When compared to males, females had significantly higher survival time (HR 0.62 95% CI 0.61-0.63, p < 0.01). Similarly, when compared to White population, Black and Asian population had lower survival time (HR 2.27 95% CI 2.11-2.43, p < 0.01 & HR 1.57 95% CI 1.14-1.68, p > 0.01) respectively. Comparing to localized disease, both regional and distant involvement had significantly lower survival time (HR 3.21 95% CI 3.15-3.28, p < 0.01 & HR 11.34 95% CI 11.07-11.61, p < 0.01) respectively. Breslow thickness had a negative correlation with survival months [regression coefficient (R) of -2.21 p < 0.01 (95% CI -2.35 to -2.07)]. Compared to patients who died before 2012, patients who died in 2012 or after had significantly better survival (HR 0.46, 95% CI 0.46-0.47, p < 0.01). Conclusions: Both, the incidence, and mortality of melanoma are rising, with more increase in age above 65 years. There appears to be an improvement in survival among patients who died after 2012, which may be an indirect indicator of the effectiveness of newer therapies. Risk factors for lower survival time were male sex, Black & Asian race, metastatic disease, and higher Breslow thickness.