Does thyroid substance improve response of breast cancer to surgical castration?

Under the aegis of the Cooperative Breast Cancer Group, 13 principal investigators studied a total of 218 female patients with metastatic carcinoma of the breast. All patients either were menstruating actively or were less than 1 year past the menopause; all had histologic proof of breast cancer and progression of tumor documented either by physical examination or by roentgenograms. Both incidence of remission and survival time were compared between patients treated either by surgical castration or by surgical castration plus thyroid substance. The incidence of remission was 27.5% for the control group and 25.7% for the group treated with thyroid substance; the survival time for the two groups was identical, with 50% surviving 30 months or longer. We conclude that the effects of surgical castration were not enhanced by the addition of thyroid substance.