Racial/ethnic disparities in risk of second primary malignancies among Diffuse Large B-cell Lymphoma survivors.

Abstract

Background: Previous studies have shown an increased risk of second primary malignancies (SPMs) among diffuse large B-cell lymphoma (DLBCL) survivors; however, this has not been comprehensively examined by race/ethnicity. Methods: From 17 United States population-based Surveillance, Epidemiology and End Results (SEER) program cancer registry areas, we identified 68,358 ≥12-month DLBCL survivors diagnosed between 2000-2022. Standardized incidence ratios (SIRs) and accompanying 95% confidence intervals (CIs) quantified SPM risk that occurred ≥12-month after DLBCL by race/ethnicity. Results: Overall, we observed 6,261 SPMs after DLBCL representing a 1.2-fold significantly increased risk (95% Confidence Interval [CI]=1.16-1.22) compared to the general SEER population and an excess of 23 cases/10,000 person-years. SPM risk varied significantly by race/ethnicity with Asian/Pacific Islanders (APIs) and Hispanics presenting higher overall risk compared to the White or Black patients (Pheterogeneity<0.001). Results from site specific analyses reported significantly higher SIRs for second hematological malignancies compared to solid cancers (SIRhemat=3.40; CI=3.15-3.68 and SIRsolid=1.07; CI=1.04-1.10); and patterns by race/ethnicity also varied significantly by these second cancer sites. Among solid SPMs, strikingly elevated risks were observed for anal cancer among the Black and Hispanic patients (SIRs of 9.29 and 8.55, respectively). Whereas, among the hematological SPMs, risks were particularly elevated for Hodgkin Lymphoma and Acute Non-Lymphocytic Lymphoma among the non-White minority populations. Conclusions: We observed substantial disparities in SPM risk by race/ethnicity, with patients belonging to minority groups experiencing higher risks. Impact: SPMs have emerged as an important challenge for DLBCL survivors, therefore, further research to understand drivers of this observed racial/ethnic heterogeneity is warranted.