Effects of low dose tamoxifen on normal breast tissue from premenopausal women

de Lima, G.R.; Facina, G.; Shida, J.Y.; Chein, M.B.C.; Tanaka, P.; Dardes, R.C.; Jordan, V.C.; Gebrim, L.H.

doi:10.1016/S0959-8049(02)00530-0

« Previous Next »European Journal of Cancer
Volume 39, Issue 7 , Pages 891-898, May 2003

Effects of low dose tamoxifen on normal breast tissue from premenopausal women

G.R. de Lima
- Department of Gynecology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
G. Facina
- Department of Gynecology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
J.Y. Shida
- Department of Gynecology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
M.B.C. Chein
- Department of Gynecology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
P. Tanaka
- Department of Gynecology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
R.C. Dardes
- Department of Gynecology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
- Department of Molecular Pharmacology & Biological Chemistry, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Medical School, Chicago, USA
V.C. Jordan
- Department of Molecular Pharmacology & Biological Chemistry, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Medical School, Chicago, USA
L.H. Gebrim
- Department of Gynecology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
- Corresponding author at: Rua Caçapava, # 49, Conjunto 12, Bairro Jardim Paulista, São Paulo-SP, Brazil. Tel.: +55-11-30612693; fax: +55-11-3088-8200

Received 19 March 2002; received in revised form 14 August 2002; accepted 17 September 2002.

Abstract

The aim of this study was to determine the effects of low doses of tamoxifen (5 and 10mg/day) for 50 days compared with the standard dose (20 mg/day) on breast biomarkers measured in normal breast tissue from premenopausal patients. A randomised double-blind study was performed using tissue from 56 premenopausal women with a diagnosis of fibroadenoma of the breast. Excisional biopsy was performed on the 50th day of therapy. Normal breast tissue samples were collected during surgery. The patients were divided in groups: A (placebo, n=11); group B (5 mg, n=16), group C (10 mg, n=14) and group D (20 mg, n=15). In this cross-sectional study, differences in the expression of Oestrogen Receptor alpha (ERα), Progesterone Receptor (PR), Ki-67, apoptotic bodies and mitotic index between the different groups after treatment can be seen on the normal breast tissue. We believe that a lower dose of tamoxifen could reduce the side-effects associated with treatment without affecting its chemopreventive activity in the breast.

Keywords: Tamoxifen, Premenopausal, Breast biomarkers, Normal breast tissue