Trends in Multiple Myeloma Incidence in the United States (US): Demographic and Geographic Considerations and Focus on Young Adults

Abstract Background: The incidence of multiple myeloma (MM) in the US is increasing among non-Hispanic (NH) White males and females as well as NH Black males (Costa LJ, Blood Advances 2017). However, more specific incidence studies accounting for geographic and age subgroups are limited. There is also a growing concern that incidence of many cancers is increasing in the younger population. Utilizing the Surveillance, Epidemiology, and End Results Program (SEER), we investigated the trends in MM incidence in the US according to demographic and geographic subgroups with a focus on the young adults. Methods: Incidence rates (case/100,0000) were calculated using SEER*Stat and 2000-2015 data from SEER-18 registries age-adjusted to the U.S. 2000 standard population. We calculated the annual percentage change (APC) of incidence rates according to age groups and stratified by sex, race, and registry. Age at diagnosis was analyzed in 10-year intervals starting at 20 years. All analyses used ICD-O-3 codes 9732/3 with microscopically confirmed MM. Results: There were 69,613 MM patients included in the analysis. The mean age at diagnosis was 68 years and decreased over time from 68.5 years in 2000 to 67.6 years in 2015. Men comprised 55.5% of the population. Patients <50 years constituted 7.9% of the population with 6.6% between 40-49 years. The incidence significantly (all p values <0.01) increased from 2000-2015 for the entire cohort (incidence 6.9-9.5; APC 1.1) and for males (8.6-9.5; 1.1) and females (5.7-6.3; 0.8). The highest increase in incidence among the age groups (Figure) was in 40-49 years (1.9-2.7; 2.1). When analyzing the trends for age groups stratified by sex, women ages 40-49 years had the highest increase in incidence (1.6-2.6; 2.4). The APCs of SEER-18 registries stratified by age and sex are reported in the Table. The highest APCs (>3.0) were observed in the registries of Atlanta, Greater Georgia, Hawaii, and New Jersey. When the SEER-18 registries were further stratified by race, white men ages 40-49 years in Seattle and New Jersey had APCs of 5.5 and 2.9 respectively, while Black women ages 40-49 years in Greater Georgia had an APC of 3.3. Only 3 groups of individuals had a significant decline in the incidence: Asian women ≥70 years in Los Angeles (APC -6.4), White women ≥70 years in Los Angeles (APC -1.9), and men 50-59 years in San Jose (APC -1.5). Conclusions: The overall incidence of MM is increasing in the US with the highest increment among young adults between the age groups 40-49 years. We observed geographic and demographic differences in the incidence rates, which may reflect genetic and environmental influences. Interestingly, a few geo-demographic subgroups had a decline in the incidence. Further research is needed to determine the reasons behind the observed trends. Disclosures Kapoor: Celgene: Research Funding; Takeda: Research Funding.