Evaluation of CEA and GCDFP-15 plasma level during hormonally induced cancer stimulation

Preliminary clinical trials indicate that transient stimulation of breast and prostate cancer growth by hormonal means may enhance tumor sensitivity to chemotherapy. In none of these studies, however, has an attempt been made to measure parameters that might reflect perturbations in cell kinetics induced by the treatment schedules. While conducting two, controlled, randomized clinical trials in advanced breast cancer and prostate cancer using a similar approach, we have measured plasma levels of two tumor markers, carcinoembryonic antigen (CEA) and breast gross cystic disease fluid protein (GCDFP-15). These served as a possible means of monitoring hormonal stimulation of tumor growth. Both markers failed to increase following administration of estrogens to patients with breast cancer and of androgens to men with prostatic carcinoma. In contrast, transient stimulation of tumor growth probably occurred as shown by exacerbation of symptoms and, in patients with prostate cancer, rise in acid phosphatase. We conclude that CEA and GCDFP-15 are not useful for monitoring pertubations in tumor cell kinetics induced by hormone stimulative protocols.