Second Primary Malignancies in Multiple Myeloma by Race

Researchers for a recent study evaluated the prevalence and characteristics of second primary malignancies (SPMs) in Black and white patients with multiple myeloma (MM) in the National Veterans Affairs (VA) healthcare system.

The analysis retrospectively reviewed electronic health record (EHR) and cancer registry data recorded in the VA’s Corporate Data Warehouse between Jan. 1, 1999, and Jan. 1, 2018. SPMs were defined as malignancies occurring after the diagnosis and treatment initiation of MM. Adjusted analyses were conducted, accounting for age, race, gender, treatment era, smoking status, and stage at MM diagnosis.

Final analysis included 8,467 veterans (97.4% were male. Self-reported race breakdown was white, 5,029 (59.4%); Black, 2178 (25.7%); and other/unknown, 1260 (14.9%). Follow-up time was 7.5 years, at which time SPMs were identified in 430 patients with MM (5.1%). A total of 982 patients underwent hematopoietic stem cell transplant (HSCT); a greater proportion of those who underwent HSCT than those who did not developed SPM (6.62% vs. 4.87%). A greater proportion of those with SPM had solid tumors (n=380, 88.3%) than hematological malignancies (n=50, 11.6%). In the solid tumor group, SPMs included: prostate cancer, 113 (29.7%); digestive tract cancers, 63 (16.6%); lung cancer, 55 (14.4%); and GU (bladder/renal/testicular), 48 (12.6%).

The median age at time of diagnosis was older for white patients than Black patients (68.2 years vs. 64.3 years). Compared to white patients, the hazard ratio (HR) for develop SPMs for Black patients was 1.21, but the adjusted HR for developing prostate cancer was 1.81.

The results were published in the Journal of Clinical Oncology.