Future Burden of Multiple Myeloma in the United States
Authors: Rosenberg Philip S , Barker Kimberly A , Anderson William F 
Published: October 2019

Abstract
BACKGROUND: Multiple myeloma (MM) is the second most common hematological malignancy in the United States (US), representing 1.4% of all new cancers. MM incidence increases rapidly with age, is twice as common among African Americans versus other groups, and is a top ten cause of cancer deaths among African Americans. Although the absolute number of new MM cases per year, or MM burden, is expected to be higher in future years because of predictable changes in the demographic profile of the US, to date no study has made detailed forecasts of future MM incidence or burden by age, race/ethnicity, and sex. In this study we construct such forecasts for the period 2011 through 2034 using cancer incidence data from the National Cancer Institute’s Surveillance Epidemiology and End Results (SEER) Program, a novel age-period-cohort (APC) forecasting model, and official projections of population sizes produced by the US Bureau of the Census.
METHODS: We obtained MM case and population data from the SEER 13 Registries Database for 1993 – 2010 for all men and women, and for non-Hispanic whites, Hispanics, Blacks, and Asian and Pacific Islanders (API). To obtain stable APC estimates for each population, we aggregated single-year data into sixteen 3-year age groups (37 – 39 through 82 – 84) and six 3-year periods (1993 – 1995 through 2008 – 2010) spanning 21 partially overlapping 6-year birth cohorts centered on birth-years 1911, 1914, through 1971. Cohort effects in our APC models enabled us to make incidence forecasts allowing for different time trends in different age groups and to extrapolate incidence trends to future birth cohorts. We estimated future numbers of new cases for each sex by race/ethnic group by multiplying APC incidence rate forecasts from SEER 13 (which covers 14% of the US) by US Census population projections for the entire US for each sex and race/ethnic group.
RESULTS: APC-based age incidence curves estimated from SEER13 data for incorporation into national projections reflected the contemporary epidemiology of MM: age incidence was higher among men than women in every race/ethnic group especially at ages 64 – 84 years, was highest in Blacks and lowest in API, and was similar in non-Hispanic Whites and Hispanics. In APC analyses, observed MM incidence from 1993 – 2010 was stable among men ages 37 – 63, increasing by around 0.5 percent per year among men ages 64 – 84, and stable among women in all age groups. Projected incidence for 2011 – 2034 was stable or slightly increasing in every age group. Projected MM burdens (numbers of new cases per year) were stable or slightly increasing for men and women ages 37 – 63. In contrast, large increases in the numbers of Americans ages 64 – 84 are expected to result in substantial increases in MM burden in this age group. In 2011-2013 we estimate a total of 11,200 new MM cases in men and 8,500 new cases in women. For 2032-2034 we forecast a total of 18,500 new cases in men and 13,700 new cases in women (65% and 61% increases, respectively). Among older persons ages 64 – 84, corresponding estimates are 7,300 male and 5,400 female cases in 2011 – 2013 approximately doubling to 14,100 male and 10,300 female cases in 2032-2034. Among older black men, who have the highest MM incidence and whose population is expected to increase by 4.3% per year, the projected increase in burden is 152% (from 1,210 to 3,050 cases per year). Among older Hispanic men (stable MM incidence, population increasing by 5.5% per year) the burden is expected to triple (from 460 to 1,370 cases per year). Among all older men, increases in MM burden above population growth reflect a modest increase in MM incidence. Increases in MM burden in other groups are in line with corresponding increases in population.
DISCUSSION: MM incidence has been relatively stable in the US during 1993 – 2010. Our forecast is that MM incidence will continue to be quite stable during 2011 – 2032. Nonetheless, because of predictable demographic shifts in the US, the number of new MM cases per year is expected to increase by 65% in men and 61% in women between 2011-2013 and 2032-2034. Almost all of these increases will occur among older Americans ages 64 – 84. In this age group, the number of new cases overall will double, and more than double among Black and Hispanic men and women.
IMPACT: Detailed forecasts quantify increasing demands for health services personnel and resources, and highlight the need for more effective MM therapies, especially for patients ages 64 – 84.

Disclosures
No relevant conflicts of interest to declare.