Some observations on the effect of a GnRH analog in ovarian cancer

Observations in healthy women led us to suppose that the increase of the tumor marker CA 125 observed during progression of ovarian cancer could be dependent on pituitary gonadotropins. Therefore we administered the GnRH-analog, DTrp 6-LH-RH, to 19 patients with progressive ovarian cancer and increasing CA 125 serum levels. When compared to 11 untreated patients, CA 125 levels increased at a considerably slower rate in 9 of 11 patients who were treated with the substance for more than 3 months. This was associated with stable disease, ranging from 4 to 20 months so far. The further analysis of 2 patients who developed an increase in CA 125 serum levels and a progression of disease during treatment demonstrated that FSH and LH levels had escaped suppression. The results support our assumption, that gonadotropins may be involved in the mechanisms leading to increasing CA 125 concentrations in ovarian cancer. The reduced increase of CA 125 and the observed stabilisation of disease during pituitary blockade offers a rationale for GnRH analogues in the therapeutic approach to this disease.