LHRH Agonist Plus Tamoxifen Improves Outcome in Young Metastatic Patients

MANCHESTER, UK—An LHRH agonist (goserelin or buserelin) plus tamoxifen (Nolvadex) provides longer survival rates than an LHRH agonist alone in young metastatic breast cancer patients, according to data from the Combined Hormonal Agents Trialists (CHAT) group presented at the San Antonio Breast Cancer Symposium.

Dr. Anthony Howell, professor of medical oncology, University of Manchester, reported results of a meta-analysis of four randomized trials (from Japan, Italy, Zeneca, and the EORTC) comparing medical castration with goserelin (Zoladex) or buserelin (Suprefact) plus tamoxifen to medical castration alone. The studies evaluated the therapies in 506 premenopausal breast cancer patients with metastatic disease.

In females, buserelin and goserelin (both approved for the treatment of prostate cancer) act on the hypothalamic-pituitary axis to disable the ovaries, thereby preventing the production of estrogen (ovarian ablation). Tamoxifen reduces estrogen production by blocking estrogen receptors.

The results showed the combined endocrine treatment to be significantly more effective than medical castration alone in terms of response rate (39% vs 30%, P = .03); progression-free survival (median, 8.7 vs 5.4 months, P < .001); and overall survival (median, 2.9 vs 2.5 years, P = .02), Dr. Howell said.

The researchers performed subgroup analyses for estrogen-receptor (ER) status, disease-free interval, and dominant metastatic site.

Although results have to be interpreted cautiously because of the small number of patients in some of the subgroups, Dr. Howell said that the “overall results point toward a trend in overall survival in favor of the combined treatment, and this trend was most pronounced in the subgroups of patients with ER-positive or unknown receptor status tumors and in those with metastasis to the bone.”

Dr. Howell said that endocrine therapy may induce early menopause in premenopausal women, but “menstruation may resume after treatment cessation.”