[Recent development of endocrine treatment for breast cancer--new drugs and new treatment methods using tamoxifen].
The characteristics and clinical efficacies of new hormonal drugs and new treatment methods for breast cancer using tamoxifen (TAM) were described. The new anti-estrogens, such as trioxifen, toremifene and droloxifen, have equal or better clinical efficacy than TAM. They showed a high response rate in postmenopausal patients with no previous treatment or estrogen receptor positive tumors. They were occasionally effective for patients who relapsed after TAM treatment. Pure anti-estrogen ICI 164, 384, with fewer estrogenic agonistic properties than TAM, and anti-estrogen TAT-59, which has been developed in Japan, are under clinical investigation. Luteinizing hormone-releasing hormone agonists, such as leuprolide, buserelin, triptrelin and goserelin, are available for premenopausal patients, and showed a 37% response rate on average. The pure aromatase inhibitors, such as 4-hydroxyandrostenedione and CGS 16, 949 A, are available for postmenopausal patients, and showed 30% and 17% response rates on average, respectively. The new pure aromatase inhibitor ZD-1033 is also under clinical investigation. TAM or toremifene as well as the calcium antagonist verapamil were proved to overcome the multiple anticancer drug resistance caused by P-glycoprotein. Clinical studies for breast cancer using high-dose TAM as a potential modulator of drug resistance have already been started in Europe and the United States. Chemoprevention of breast cancer using TAM, which started in the U.S., was described.
Sonoo
H
H
Department of Surgery, Kawasaki Medical School, Kurashiki, Japan.
Kurebayashi
J
J
D000970:Antineoplastic Agents / Q000627:therapeutic use; D047072:Aromatase Inhibitors; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000517:prevention & control; D004351:Drug Resistance; D004965:Estrogen Antagonists / Q000627:therapeutic use; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000627:therapeutic use; D006801:Humans; D013629:Tamoxifen / Q000008:administration & dosage / Q000627:therapeutic use*
D000970:Antineoplastic Agents; D047072:Aromatase Inhibitors; D004965:Estrogen Antagonists; D013629:Tamoxifen; D007987:Gonadotropin-Releasing Hormone