Modulatory effects of estrogen on immunologic responsiveness. III. Effect of hormonal versus nonhormonal therapy on tumor-associated immunity in prostatic cancer.

In vitro pretreatment of peripheral blood leukocytes (PBL) from patients with prostatic cancer with therapeutically significant levels of diethylstilbestrol diphosphate (DES-P) has been shown to suppress cell-mediated tumor-associated immunity (TAI). In the present retrospective evaluation of TAI in 27 patients with prostatic cancer, prior to and following the receipt of nonhormonal and hormonal, ie, estrogen and/or orchiectomy, therapy, patients receiving hormonal therapy possessed significantly (p less than 0.05) lower levels of TAI, irrespective of the in vitro pretreatment of their PBL with DES-P. Suppression of TAI by in vitro pretreatment of PBL with DES-P and in prostatic cancer patients receiving estrogen therapy parallels and extends earlier observations of the estrogenic suppression of nonspecific, mitogen-induced cellular responsiveness. The clinical relevance of the immunosuppressive effects of hormonal therapy on tumor-host responsiveness is considered in view of the present and previous studies.