New data presented at ASCO Annual Meeting 2023 suggest racial disparities may lead to increased risk of second primary malignancies (SPMs) among patients with diffuse large B-cell lymphoma (DLBCL) in the United States. Researchers explored a large-scale population-based database and found substantial disparities in SPM risk by race/ethnicity.
Pragati Advani MD, MPH, an assistant professor of Oncology at Roswell Park Comprehensive Cancer Center, Buffalo, New York noted in an email interview that risks of second primary malignancy were significantly higher in Asian/Pacific Islander and Hispanic DLBCL survivors compared to White patients and that disparities in race/ethnicity in these patients existed beyond their initial cancer diagnosis well into their survivorship.
Using the United States population-based Surveillance, Epidemiology and End Results (SEER) program cancer registry data, the researchers identified 57,262 patients with ≥12-month first-primary DLBCL diagnosed between 2000 and 2019. When looking at standardized incidence ratios (SIRs), the risk for SPMs was significantly higher in Asian/Pacific Islander (API) and Hispanic patients compared to the general population.
All the patients were followed beginning 12 months after initial DLBCL diagnosis and until their first diagnosis for a secondary cancer, death, age 85, last follow-up, or end of study (December 31, 2020). The researchers identified 5210 SPMs after DLBCL and there was a 1.2-fold significantly increased risk for non-White patients compared to the general population. The difference was an excess of 24 cases per 10,000 person-years.
The SIRs for all second cancers combined varied significantly by race/ethnicity with APIs. Hispanics had higher overall SPM risk with 1.34 (95% CI, 1.23-1.46). The SIR for White was patients 1.17 (95% CI, 1.14-1.21) and for Black patients was 1.17 (95% CI, 1.04-1.30). “To the best of our knowledge, it is one of the largest population-based studies to examine risk of second cancers among DLBCL survivors, and examined disparities by race/ethnicity in the contemporary treatment era,” said Dr Advani.
When looking at the age of diagnosis, heterogeneity by race/ethnicity was even more pronounced in patients with DLBCL diagnosed at a younger age. The same was true for those who were ≥5 years into their survivorship and those who had received chemotherapy, or those who had received no radiation as their initial treatment.
Heterogeneity by race/ethnicity in SPM risk was significant regardless of the stage of the disease. However, SIRs for SPM were significantly higher for patients with advanced stage DLBCL compared to those with localized/regional disease. Analyzing results for site specific disease, the researchers found significantly higher overall SIRs for second hematological malignancies for hematologic cancers (SIR, 3.51; 95% CI, 3.22-3.82) compared to solid cancers 1.08 (95% CI, 1.05-1.11).
In terms of clinical implications, these findings may have dual motivations: to gain etiologic insight into racial/ethnic variation in SPMs after DLBCL as well as in DLBCL risk itself, and second to inform more personalized cancer surveillance/prevention recommendations among DLBCL survivors, according to Dr Advani. “In terms of treatment, we did find that patients who had received any chemotherapy for their initial DLBCL treatment were significantly more at risk for a second malignancy.”
However, SEER data do not provide detailed treatment data, and so there is a need for additional studies. The current study showed significant variety in the secondary tumor type and race/ethnicity. It was most notable for secondary primary anal cancer, Hodgkin’s lymphoma (HL), and acute non-lymphocytic leukemia (ANLL; P <0.001 for each). There were striking differences for second primary anal cancer, HL, and ANLL among the Black patients, and HL among the APIs and Hispanic DLBCL survivors compared to the White patients.
“These findings form a strong base to support the rationale for future studies to include detailed genetic, environmental, behavioral, and treatment-related data, to better understand specific drivers of the observed racial ethnic heterogeneity in SPM risk after DLBCL,” Dr Advani noted.
Advani PG, Attwood K, Herr M, et al. Racial and ethnic disparities in risk of second primary malignancies among diffuse large B-cell lymphoma survivors. ASCO 2023. June 2-6, 2023. Abstract 7567.