ONDANSETRON DOES NOT STIMULATE PROLACTIN-RELEASE IN BREAST-CANCER PATIENTS

Aims and background: Prolactin (PRL) may be a tumor growth factor, mai nly for breast cancer. The antidopaminergic drugs commonly used in the treatment of chemotherapy-induced vomiting stimulate PRL release, and this finding could represent a potentially negative biologic event fo r cancer patients. This study was performed to analyze PRL response to the serotonin-type 3 receptor antagonist ondansetron, a new active dr ug in the treatment of vomiting due to chemotherapy, in cancer patient s. Methods: The study included 8 premenopausal breast cancer patients undergoing adjuvant chemotherapy. Ondansetron was given intravenously at a dose of 8 mg, and venous blood samples were drawn at 0, 20, 60 an d 120 min. The result were compared to those seen in 10 breast cancer patients treated with metoclopramide (10 mg. i.v.). Results: PRL mean levels significantly increased in response to metoclopramide. In contr ast, no significant changes in PRL mean values occurred after ondanset ron injection. Conclusions: The study showed that ondansetron, whose e fficacy in the treatment of chemotherapy-induced vomiting is well know n, does not stimulate the tumor growth factor PRL in cancer patients, in contrast the the action of the most commonly used antidopaminergic drugs.