Effect of therapeutic radiation on peripheral blood lymphocytes in patients with carcinoma of the breast.

Effects of radiation therapy for carcinoma of the breast on responsiveness to mitogens of blood lymphocytes of patients at different clinical stages were analysed. Patients at different clinical stages had comparable numbers and responses of lymphocytes. During therapy the mean lymphocyte numbers decreased to 31 per cent of the pre-treatment value and mean responses to mitogens in whole-blood cultures decreased to 15 to 39 per cent of pre-treatment values. Similar decreases occurred whether or not mastectomy was performed.