Second primary malignancy in diffuse large B-cell lymphoma patients: A SEER database analysis

Previously, studies have shown increased risks of second primary malignancies (SPM) after Hodgkin lymphoma and non-Hodgkin lymphoma. Nevertheless, investigation quantifying risks of SPM in patients with diffuse large B-cell lymphoma (DLBCL) remains scarce.

We used the US population-based SEER 9 Regs Custom Data, Nov 2016 Sub to analyze the risks of SPM in patients with DLBCL. The standardized incidence ratio (SIR), absolute excess risk (AER), and 95% confidence intervals (CIs) were calculated.

Among patients with DLBCL as a primary malignancy, 3751 patients had second cancer episodes identified, with a SIR of 1.19 (95% CI: 1.16-1.23, P < 0.05). There was a significantly higher risk of tumors/malignancies in the following sites of patients with DLBCL compared with the general population: Oral cavity and pharynx, hepatobiliary system, head and neck, thorax, bone and soft tissue, skin, breasts, urinary tract, and endocrine system. Additionally, leukemia, myeloma and lymphoma, and Kaposi sarcoma occurred more frequently in patients with DLBCL than in the general population. Risk for a subsequent colon/rectum/anus cancer, bone and joint malignancy, and melanoma were significantly elevated in DLBCL patients received beam radiation, while the risk for these malignancies was not significantly increased in those without a radiation record. Notably, for patients under 45 years of age, the risk for SPM was higher than their counterparts in other age groups.

Our results offer insight into the occurrence of SPM among patients with DLBCL, suggesting awareness of the increased risk of subsequent malignancies is crucial for DLBCL survivors as well as for their physicians.