CLL/SLL Treatment and Risk for Other Cancers: Insights From a Recent Study on Veterans

Initial treatment with monoclonal antibodies alone did not boost the risk for other cancers (OCs) in a group of US veterans who had been diagnosed with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL), but initial treatment with chemoimmunotherapy was associated with a significant increase of OCs, according to results of a recently presented study.¹

Helen Ma, MD, of the VA Long Beach Health System, and the University of California, presented data from a retrospective case-control analysis at the 66th American Society of Hematology (ASH) Annual Meeting & Exposition held in San Diego, CA.

The analysis looked at data on patients diagnosed with CLL/SLL during or after 2016 using the Veterans Affairs Central Cancer Registry (VACCR). Cases were patients with CLL/SLL diagnosed with incident OCs, excluding nonmelanoma skin cancers. Frontline treatment with chemoimmunotherapy, monoclonal antibodies alone, or targeted therapies, such as Bruton tyrosine kinase inhibitors or BCL2 inhibitors, was the exposure of interest compared with patients on active surveillance.

The researchers identified 5244 patients with CLL/SLL who met inclusion criteria, which was described as patients with CLL/SLL diagnosed with incident OCs, excluding nonmelanoma skin cancers. Sixty-six percent of the patients were managed with active surveillance, and 34% of patients required frontline treatment with either ibrutinib (776, 59%), acalabrutinib (246, 19%), zanubrutinib (129, 10%), venetoclax (164, 12%), or a combination of ibrutinib and venetoclax in a clinical trial; 1318 (25%) patients were treated with targeted therapy, 329 (6%) with chemoimmunotherapy, and 137 (3%) with monoclonal antibodies alone.

Ten percent of the patients were diagnosed with OCs, including neoplasms of the lung, prostate, gastrointestinal tract, hematologic malignancies, melanoma, kidney and bladder, head and neck, and other/unknown cancers.

Logistic regression analysis, which adjusted for age at diagnosis, race, and use of tobacco and alcohol, noted a significant association between treatment with chemoimmunotherapy and an increased risk of OCs. Specifically, patients treated with chemoimmunotherapy had a 2.4-fold higher risk of developing OCs compared with those under active surveillance (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.7-3.3; P<.0001).

In contrast, patients treated with monoclonal antibodies alone or targeted therapies showed no significant increase in OCs risk. The OR for monoclonal antibodies alone was 1.4 (95% CI, 0.8-2.6), and for targeted therapies, the OR was 1.1 (95% CI, 0.9-1.4), both of which were not statistically significant when compared with patients on observation.

Reference

1. Ma H, Parikh S, Aevedo RS, et al. First-line treatment choice and risk of other malignancies in US veterans diagnosed with chronic lymphocytic leukemia and small lymphocytic lymphoma program: oral and poster abstracts session: 902. Presented at: 66th ASH Annual Meeting & Exposition. December 7-10, 2024; San Diego, CA. Abstract 5038.