Effect of treatment with diethylstilbestrol-polyestradiol phosphate or estramustine phosphate (estracyt) on natural killer cell activity in patients with prostatic cancer.

We evaluated the effect of treatment of patients with prostatic cancer with estramustine phosphate or the combination diethylstilbestrol-polyestradiol phosphate on the natural killer cell activity in peripheral blood. Although estramustine phosphate did not affect natural killer cell activity, diethylstilbestrol-polyestradiol phosphate substantially reduced natural killing after a treatment period of 1 week. The activity was only slightly further lowered after 4 weeks of treatment. Possible clinical implications of the difference in susceptibility of natural killer cells to these agents are discussed.