title: The influence of tamoxifen treatment on the oestrogen receptor in metachronous contralateral breast cancer.
abstract: Adjuvant tamoxifen treatment reduces the occurrence of contralateral breast cancer (CBC). The aim of the study was to investigate the hypothesis that adjuvant tamoxifen reduces the occurrence of oestrogen-receptor (ER)-positive CBC, but not the growth of ER-negative CBCs, and to examine survival after diagnosis of CBC. For the study, ER status was immunohistochemically assessed in CBCs of 35 tamoxifen-treated patients and 115 patients without previous hormonal treatment. Cases were retrieved from a series of patients treated from 1984 to 1995 at nine hospitals. The interval between ipsi- and contralateral breast cancer was at least 1 year. It was seen that the proportion of patients with an ER-negative CBC was significantly higher among those with prior tamoxifen treatment: 37% vs 18% (P=0.047). No difference between the two groups in overall and disease-specific survival following CBC was found. However, the stage differed for both groups: tamoxifen users more often had node-positive contralateral disease (P= 0.045). In conclusion, metachronous CBCs developing after 1-3 years of tamoxifen treatment are more often ER-negative breast cancers. So far this does not seem to have a major impact on survival.
authors.affiliation: Department of Surgery, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Ziekenhuis Plesmanlaan, Amsterdam, The Netherlands. reinie@kaas.nl
authors.forename: R
authors.initials: R
authors.lastname: Kaas
authors.forename: J L
authors.initials: JL
authors.lastname: Peterse
authors.forename: A A M
authors.initials: AA
authors.lastname: Hart
authors.forename: A C
authors.initials: AC
authors.lastname: Voogd
authors.forename: E J T
authors.initials: EJ
authors.lastname: Rutgers
authors.forename: F E
authors.initials: FE
authors.lastname: van Leeuwen
mesh_terms: D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D011960:Receptors, Estrogen / Q000378:metabolism*; D013629:Tamoxifen / Q000627:therapeutic use*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D011960:Receptors, Estrogen; D013629:Tamoxifen