Sustained lymphocyte decreases after treatment for early breast cancer
Julia Dixon‐Douglas, Balaji Virassamy, Kylie Clarke, Michael L. Hun, Stephen J. Luen, Peter Savas, Courtney T. van Geelen, Steven David, Prudence A. Francis, Roberto Salgado, Stefan Michiels, Sherene Loi
Abstract
The role of adaptive immunity in long-term outcomes in early breast cancer is increasingly recognised. Standard (neo)adjuvant chemotherapy can have adverse effects on immune cells. We conducted a retrospective longitudinal study of full blood counts (FBC) of 200 patients receiving (neo)adjuvant chemotherapy for early breast cancer at a single institution. FBC results at four time points from pre-treatment to 12 months post-chemotherapy were analysed. Flow cytometry was performed for patients with matched pre- and post-chemotherapy peripheral blood mononuclear cell samples. A significant decrease in absolute lymphocyte count at 12 months post-chemotherapy was observed ( p < 0.01), most pronounced in pre-menopausal patients ( n = 73; p < 0.01), patients receiving dose-dense chemotherapy regimens ( n = 60; p < 0.01) and patients receiving adjuvant radiotherapy ( n = 147, p < 0.01). In pre-menopausal patients, significant changes in CD4 + T cells subsets post-chemotherapy were observed. Further investigation, including long-term clinical outcomes, is needed to meaningfully improve long-term anti-tumour immunity.