{'fraction_non_alphanumeric': 0.03201970443349754, 'fraction_numerical': 0.014778325123152709, 'mean_word_length': 5.372549019607843, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
[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.