The immunological status of breast cancer patients during treatment with a new antiestrogen, toremifene.

The immune status of breast cancer patients was followed during antiestrogen treatment for at least 1 year or until progression of the disease. Twelve post-menopausal women with advanced estrogen-receptor-positive breast cancer were treated with a novel antiestrogen, toremifene. Immune functions were determined before the start of the treatment and at 3, 6, and 12 months. For NK cell cytotoxicity testing there were 74 healthy controls and for T cell subset measurements 28 healthy controls. No statistically significant changes in the T cell subsets or NK cell cytotoxicity were observed during treatment. However, throughout toremifene treatment patients had fewer CD4 cells (T helper lymphocytes) than did the controls. Cancer patients had higher pretreatment B cell values than the controls, P = 0.01, but during the first months of toremifene treatment B cell values decreased and remained within the normal range thereafter. A positive effect on mitogen-stimulation tests with phytohemagglutinin (PHA) and concanavalin A (ConA) was observed during the first months of treatment (P = 0.01 for PHA and 0.03 for log [ConA] and a stabilization at the higher level thereafter. These results indicate that toremifene has a stimulatory effect on cell-mediated immunity in breast cancer patients.