Relationship between thyroid-pituitary function and response to therapy in patients with recurrent breast cancer

In this study, thyroid (T3, T4, free T3, free T4) and pituitary function (thyrotropin (TSH), growth hormone (GH), prolactin (PRL)) in 38 patients with recurrent breast cancer were examined. The patients were divided into three groups according to their response to the therapy. There were 16 partial response (PR), 10 no change (NC) and 11 progressive disease (PD) patients. The maximum and the minimum value for each hormone throughout the course of treatment were compared between three groups. The PD group showed significantly lower minimum T3 levels than the other two groups (p < 0.05). The maximum TSH level in the PD group was significantly higher than that of the other groups. The minimum TSH level in the PD group was significantly lower than that in the PR group (p < 0.05). The minimum TSH level in the NC group was also lower than that in the PR group. The maximum PRL level in the NC and the PD group was higher than that in the PR group (p < 0.05, p < 0.01, respectively). The tumors of the patients with temporal increase of TSH level were resistant to all subsequent therapies. These five patients died within four months followed by decreasing of the TSH level. It is concluded that thyroid and pituitary function, especially free T4, TSH and PRL, are predictive indicators of therapeutic response and the prognosis of the patients with recurrent breast cancer.