title: Uterine side effects of treatment with tamoxifen.
abstract: OBJECTIVE
  To assess a causal the relationship between endometrial lesions and tamoxifen therapy in patients with breast cancer.
  
  
  METHODS
  Prospective longitudinal study and cross-sectional study.
  
  
  METHODS
  Cancer prevention unit at Basurto Hospital, Bilbao.
  
  
  METHODS
  Three populations of breast cancer were studied: 43 before the beginning of tamoxifen; 78 after 5-72 months of tamoxifen, and 34 before tamoxifen and after 12-24 months of tamoxifen treatment (PAIRED GROUP). All of them were systematically studied with CO(2) diagnostic hysteroscopy and endometrial biopsy by the same clinician.
  
  
  RESULTS
  Before tamoxifen, the following endometrial lesions were detected: endometrial polyps 9.3%; endometrial cysts 16.3%; synechiae 11.6%. In the paired group the ingestion of tamoxifen shows a direct causal effect with a significant increase in endometrial polyps (11.8% vs. 29.4%; OR=13; CI=7.9-18.1), in endometrial cysts (17.7% vs. 55.9%; OR=7.5; CI=5. 9-9.1) and in synechiae (14.7% vs. 35.5%; OR=8; CI=4.7-11.3). In the group under tamoxifen for 5-72 months, one endometrial carcinoma was detected.
  
  
  CONCLUSIONS
  Breast cancer patients have a number of endometrial lesions before undergoing any hormonal therapy. Tamoxifen significantly increased benign endometrial lesions, usually after less than one year of treatment. No cases of endometrial carcinoma was found in our series of 34 patients with 1-2 years of tamoxifen treatment, and 1/78 in patients with 5-72 months of tamoxifen.
authors.affiliation: Department of Obstetrics and Gynecology, Basurto Hospital, Bilbao, Spain. dandia@hbas.osakidetza.net
authors.forename: D
authors.initials: D
authors.lastname: Andía
authors.forename: P
authors.initials: P
authors.lastname: Lafuente
authors.forename: R
authors.initials: R
authors.lastname: Matorras
authors.forename: J M
authors.initials: JM
authors.lastname: Usandizaga
mesh_terms: D001706:Biopsy; D001943:Breast Neoplasms / Q000517:prevention & control; D003430:Cross-Sectional Studies; D003560:Cysts / Q000139:chemically induced; D016889:Endometrial Neoplasms / Q000139:chemically induced; D004717:Endometrium / Q000473:pathology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D011127:Polyps / Q000139:chemically induced; D013629:Tamoxifen / Q000009:adverse effects* / Q000627:therapeutic use; D014591:Uterine Diseases / Q000139:chemically induced*
chemical_list: D013629:Tamoxifen