Cancer
Population differences in the association between lactate dehydrogenase and survival outcomes in multiple myeloma Malaika Jade Mason* Malaika Jade Mason Mason University of Chicago
Elevated lactate dehydrogenase (LDH) is an established prognostic factor in multiple myeloma (MM). Studies of lymphoma and some solid tumors have reported racial differences in elevated LDH and survival, but whether this difference exists in MM is largely unknown. We evaluated the association between elevated LDH and overall survival (OS)/progression-free survival (PFS) among African American (AA) and European American (EA) patients with newly diagnosed MM in two prospective cohorts: the UChicago Multiple Myeloma Epidemiology study (UCMME) and the Multiple Myeloma Research Foundation (MMRF) CoMMpass study. Vital status for both studies was ascertained from the National Death Index. LDH was defined as normal (≤240 U/L) or elevated (>240 U/L). OS was defined as time from diagnosis to death from any cause. PFS was defined as time from diagnosis to a progression event or death. Multivariable Cox proportional hazards models adjusted for age and relevant clinical factors were used to calculate HRs and 95% CIs for survival outcomes. Among patients with available LDH measurements (UCMME: EA=325, AA=124; MMRF: EA=441, AA=88), 147 deaths (EA=94, AA=49) occurred in the UCMME cohort (median follow-up 69.2 months) and 134 deaths (EA=105, AA=29) occurred in the MMRF cohort (median follow-up 38.3 months). In both cohorts, elevated LDH was associated with worse OS [UCMME HR: 1.7 (1.2, 2.5); MMRF HR: 1.6 (1.0, 2.3)]. When stratified by race, elevated LDH was associated with worse OS among EA patients [UCMME HR: 2.0 (1.3, 3.3); MMRF HR: 1.6 (1.0, 2.5)], while elevated LDH was not significantly associated with OS for AA patients in either cohort [UCMME HR: 1.3 (0.7, 2.3); MMRF HR: 0.4 (0.1, 1.3)]. Similar patterns were observed for PFS. In both datasets, elevated LDH was associated with worse OS and PFS for EA patients, but not AA patients. Our findings suggest that whereas elevated LDH has been associated with poor MM outcomes, this needs to be separately considered for AA patients.