Smoldering multiple myeloma (SMM) is less likely to progress to active multiple myeloma (MM) among African American patients compared with White patients, according to the results of a retrospective study presented at the 19th Annual Meeting and Exposition of the International Myeloma Society.

The incidence of MM is higher among African Americans, and MM outcomes are worse among these patients. However, it is unknown if race affects the risk of SMM progression to MM.

This retrospective study evaluated data from 575 patients diagnosed with SMM at Memorial Sloan Kettering Cancer Center between 2000 and 2019. African Americans represented 13% of the cohort. The mean age of the cohorts was 61 among African Americans and 64 among Whites, and 58% and 44% of patients in each group were female, respectively. The Mayo 2018 risk scores was similar between the groups.

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The median follow-up was 3 years among African Americans and 4 years among Whites in the cohort. A multivariate analysis demonstrated that African American race was associated with a significant reduction in risk for SMM progression (hazard ratio [HR], 0.41; 95% CI, 0.17-0.95; P =.039).

The time to progression was significantly longer among African Americans, with a median of 9.7 years compared with 6.2 years among Whites (P =.027). The 2- and 5-year progression rates were 12.6% and 34% for African Americans, respectively, compared with 20.1% and 44.6% for Whites, respectively.

However, when stratified by age, the risk of progression was similar between races for patients aged younger than 65. The risk of progression remained lower for African Americans aged 65 or older with a median of 9.8 years compared with 5.2 years among Whites of the same age group (P =.02).

Other factors associated with SMM progression were 20% or higher of bone marrow plasma cells (HR, 1.8; 95% CI, 1.2-2.8; P =.007), an M-spike of 2 g/dL or higher (HR, 3; 95% CI, 1.8-4.8; P <.001), FLC ratio of greater than 20 (HR, 2.5; 95% CI, 1.6-3.7; P <.001), and an albumin level less than 3.5 g/dL (HR, 2; 95% CI, 1.1-3.6; P =.019).

The authors concluded that “the prognostic impact of tumor sidedness in ovarian cancer is small and perhaps still inconclusive.” They added that this “needs to be investigated in well conducted prospective studies with genetic profiling and deep assessment of involved lymph nodes.”

Disclosures were not available for this presentation.


Akhlaghi T, Maclachlan K, Korde N, et al. African American patients with smoldering multiple myeloma may have a lower risk of progression compared to white patients. Presented at IMS 2022; August 25-27, 2022. Abstract P-171.