Clinical Impact of Postoperative Tamoxifen Therapy in Patients with Breast Cancer

ABSTRACT

BACKGROUND: Tamoxifen is one of the most widely prescribed drug in patients with breast cancer and has been proven to have a favorable effect on disease-free survival (DFS) and overall survival (OS) when given as an adjuvant therapy. However, there is little known about the effects of tamoxifen in Korean patients with breast cancer. The purpose of this report was to obtain the informations about tamoxifen as an adjuvant therapy for the prospective study hereafter. METHODS: The medical records of 349 patients with breast cancer from Jan. 1 1988 to Dec. 31 1995, who have no distant metastasis and have had adjuvant therapies after surgery with appropriate follow up, were reviewed retrospectively. The univariate analysis of various prognostic factors, such as age, menopausal status, stage, steroid receptor status, operation method, chemotherapy, and the relationship of tamoxifen therapy with them were analyzed using SAS program. RESULTS: 1) The benefit of Tamoxifen administration in DFS was observed in women 40-49 and over 60 years of age, premenopausal women, tumors with the size of 2-5 cm, Stage IIb, progesterone receptor positive tumors, and for patients treated with chemotherapy and CAF (Cyclophopamide Adriamycin 5-Fluorouracil) regimen of it. Tamoxifen also improved OS in women over 60 years of age, Stage I or IIb, and for the patients treated with chemotherapy and CAF regimen (P<0.05, log rank or Wilcoxon test). 2) The relapse or death rate decreased linearly as the duration of tamoxifen administration was extended (P=0.001, Cochran-Armitage test). The Kaplan-Meier disease free and overall survival rates of the four groups of duration were significantly different (P=0.0001, logrank test). CONCLUSIONS: There is a benefit of tamoxifen therapy in the patients aged 60 or older, tumors with the size of 5 cm or less, Stage IIb or less, and for the patients treated with chemotherapy and CAF regimen of it. This benefit is increasing as the duration of tamoxifen administration is extended. Thebenefit of tamoxifen is unreliable in the patients aged 40-49, premenopausal women and progesterone receptor positive tumors, possibly because of bias in those subsets.