Multiple Myeloma Unusual in Younger Patients, Behaves Differently

BETHESDA, MD — Multiple myeloma (MM) is extremely unusual in adolescents and young adults (AYAs) younger than 45, and, when it does occur, often has some unusual features.

Researchers from Walter Reed National Military Medical Center here and David Grant USAF Medical Center in Fairfield, CA, used real-world data from the American Society of Clinical Oncology’s CancerLinQ Discovery (CLQD) MM dataset and SEER to characterize demographics and outcomes of adolescent and young adult (AYA) patients with multiple myeloma.

In the report in Clinical Lymphoma, Myeloma & Leukemia, the study team’s focus was on young MM patients in the United States in the modern-treatment era. Frequencies of second primary malignancies, clinical venous thromboembolism (VTE), and infections were assessed, as were the overall survival and cause of death.¹

Included in the study were 1,946 AYA patients with MM from SEER and 1,334 from CancerLinQ.

In terms of SPMs, the researchers advised that AYAs were more likely to develop acute lymphocytic leukemia (ALL) (RR 2.6, P = 0.003) and acute myeloid leukemia (AML) (RR 1.7, P = 0.034), and less likely to develop nonmelanoma skin cancer (RR 0.2, P = 0.001) and prostate cancer (RR 0.1, P = 0.013) than MM patients 45 and older.

“AYAs were at lower risk of VTE (RR 0.75, P = 0.002) and slightly higher risk of infections (RR 1.11, P = 0.002),” the authors wrote. “Median OS among AYA MM patients was significantly longer than MM patients ≥ 45 in both datasets.”

The study noted that, in the SEER cohort, characteristics associated with lower hazards of mortality included female sex (HR 0.74, P = 0.003), non-Hispanic ethnicity (HR 0.73, P = 0.005) and annual household income ≥ $65,000 per year (HR 0.67, P = 0.001).

In the CLQD cohort, OS was significantly influenced by female sex (HR 0.6, P = 0.048), the researchers pointed out, adding, “Race did not have a statistically significant impact on OS in either cohort. Most AYAs died of MM (68.3%), other primary malignancy (7.5%, mostly leukemia) and cardiovascular events (5.2%). Infections accounted for 3.2% of deaths.”

1. Gibson S, Thornton J, Sunderland K, Pham K, DeStefano C. Multiple Myeloma in Adolescent and Young Adults: An ASCO CancerLinQ and SEER Analysis. Clin Lymphoma Myeloma Leuk. 2023 Jul 28:S2152-2650(23)00215-X. doi: 10.1016/j.clml.2023.07.005. Epub ahead of print. PMID: 37541820.