[Possibilities in drug therapy in prostatic carcinoma]

Abstract

At the time of diagnosis, about two thirds of all prostate cancers are not organ-confined anymore and, thus, are not eligible for local therapy with curative intention. Drug treatment of these tumors is purely palliative; so far, no survival advantage could be demonstrated. Therefore, the goal of systemic therapy is prevention or palliation of complications such as obstructive symptoms and pain. The first step in drug therapy of advanced prostate cancer is always withdrawal of male sex hormones; 70 to 80% of the patients respond favorably. Orchiectomy and LH-RH analogues are considered equal with regard to effectiveness and side effects. However, the surgical approach is less expensive and does not depend on the patient's compliance. Estrogens are rarely used anymore, because they can cause cardiovascular complications. In asymptomatic patients, the question remains to be answered if androgen withdrawal should be performed immediately at the time of diagnosis or delayed in case of possible symptoms. Antiandrogen agents block directly the androgen receptors in the prostatic cell. However, monotherapy with antiandrogens is not yet an established procedure. Instead, since 5% of circulating androgens are of adrenal origin, antiandrogens are combined with either orchiectomy or LH-RH analogues for total androgen suppression. The benefit of maximal androgen ablation is a highly controversial issue nowadays. In most cases, tumor progression after hormonal therapy is due to hormone-refractory cells. Cytotoxic chemotherapy is largely ineffective in treating prostate cancer. Commonly used chemotherapeutic substances lead to temporary remission in 10 to 20% of patients at most.