Composition of Peripheral Leukocytes in Breast Cancer Survivors: Clinical Implications

By: Joshua D. Madera, MD
Posted: Monday, May 13, 2024

Evidence of long-term changes in peripheral leukocyte composition is present in breast cancer survivors compared with women who remained free of breast cancer, according to a cohort study published in JAMA Network Open. These findings may be explained by molecular changes attributable to chemotherapy or radiotherapy, which may make breast cancer survivors more susceptible to developing chronic diseases. Therefore, additional studies investigating the impact of these long-term changes are warranted, explained Jacob K. Kresovich, PhD, of H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida, and colleagues.

“Treatment-associated immunologic changes have important implications for long-term health among survivors of breast cancer,” commented the study authors. “These findings add to our understanding of the biological changes that underlie the long-term health of breast cancer survivors.”

The study encompassed a total of 410 women who were either breast cancer survivors (n = 185) or who remained free of breast cancer. Blood samples were collected from all patients at baseline and at follow-up visits for DNA profiling. A genome-wide methylation screening tool was used to provide estimated percentages of the 12 circulating leukocyte subsets analyzed.

The study authors reported a significant reduction in the percentage of circulating eosinophils (–0.45%), memory B cells (–0.22%), and total CD4-positive helper T cells (–1.50%) present in breast cancer survivors compared with those who remained free of breast cancer. In addition, breast cancer survivors had elevated percentages of circulating naive B cells (0.46%). Furthermore, analyses in breast cancer survivors revealed a significant association between exposure to radiotherapy and a reduction in total CD4-positive T-cell levels. Similarly, a significant association was identified between chemotherapy and increasing levels of naive B cells. Moreover, no significant associations were found between surgery or endocrine therapy and changes in the number of leukocytes in this patient population.

Disclosure: The study authors reported no conflicts of interest.

JAMA Network Open