In an analysis reported in JAMA Network Open, Jacob K. Kresovich, PhD, and colleagues identified differences in circulating leukocyte subsets between women who were diagnosed and treated for breast cancer vs those not diagnosed with breast cancer.
As stated by the investigators: “Changes in leukocyte composition often precede chronic disease onset. Patients with a history of breast cancer…are at increased risk for subsequent chronic diseases, but the long-term changes in peripheral leukocyte composition following a breast cancer diagnosis and treatment remain unknown.”
Jacob K. Kresovich, PhD
Study Details
The study involved data on paired blood samples in women enrolled in the The Sister Study, a U.S.-nationwide prospective cohort study; samples were obtained at baseline (July 2003 to March 2009) and follow-up (October 2013 to March 2015), with a mean follow-up interval of 7.6 ± 1.4 years. A total of 410 women were included in the current analysis, including 185 breast cancer survivors who had been diagnosed and treated for breast cancer after enrollment and before the second blood draw and 225 women who remained free of breast cancer over a comparable follow-up period.
Key Findings
Compared with women who did not develop breast cancer, breast cancer survivors had decreased percentages of circulating eosinophils (−0.45%, 95% confidence interval [CI] = −0.87% to −0.03%, P = .03), total CD4-positive helper T cells (−1.50%, 95% CI = −2.56% to −0.44%, P = .01), and memory B cells (−0.22%, 95% CI = −0.34% to −0.09%, P = .001), as well as increased percentages of circulating naive B cells (0.46%, 95% CI = 0.17%–0.75%, P = .002).
Among breast cancer survivors, radiotherapy was associated with a decreased percentage of total CD4-positive T cells (–2.57%, 95% CI = –4.26% to –0.88%, P = .003), and chemotherapy was associated with an increased percentage of naive B cells (0.66%, 95% CI = 0.20%–1.12%, P = .005). No meaningful associations of leukocyte changes were observed with surgery or endocrine therapy.
The investigators concluded: “In this cohort study of 410 women, breast cancer survivors experienced lasting changes in peripheral leukocyte composition compared with women who remained free of breast cancer. These changes may be related to treatment with chemotherapy or radiotherapy and could influence future chronic disease risk.”
Dr. Kresovich, of the Departments of Cancer Epidemiology and Breast Oncology, H. Lee Moffitt Cancer Center & Research Institute, is the corresponding author of the JAMA Network Open article.
Disclosure: The study was supported by grants from the Intramural Research Program of the National Institutes of Health. For full disclosures of the study authors, visit jamanetwork.com.
