The operation of radical mastectomy in patients with carcinoma of the breast increased the number of lymphocytes in the peripheral blood while radiotherapy caused a decrease for at least six months. The DNA synthesis of peripheral blood lymphocytes cultured with phytohemagglutinin (PHA) was not significantly changed by operation but was increased for six months by local radiotherapy. The results, therefore, suggest that operation increased and local radiotherapy had little effect on the number of thymic-dependent lymphocytes (T-cells). Prognosis was not related to the lymphocyte count nor to the response of lymphocytes to PHA before or after treatment. The T-cells, within the range of observed values, were, therefore, probably not important in determining the prognosis in patients with carcinoma of the breast.
McCredie JA, Inch WR, Sutherland RM. Peripheral Blood Lymphocytes and Breast CancerEffects of Operation and Radiotherapy. Arch Surg. 1973;107(2):162-165. doi:10.1001/archsurg.1973.01350200036010