title: Increased risk of endometrial abnormalities in breast cancer patients taking tamoxifen: the need for gynaecologic surveillance.
abstract: OBJECTIVE
  To evaluate the risk of abnormally thickened endometrium associated with tamoxifen treatment in postmenopausal breast cancer patients.
  
  
  METHODS
  Two groups of asymptomatic postmenopausal breast cancer patients were recruited in the study. The first consisted of 70 patients taking 20mg/day of tamoxifen for at least 6 months. The second group included 140 patients without tamoxifen treatment. Endometrial evaluation using transvaginal ultrasonography (TVS) was conducted for all patients. Fractional curettage was carried out for patients whose endometrial thickness was greater than 5 mm on TVS.
  
  
  RESULTS
  The prevalence of abnormally thickened endometrium (greater than 5 mm on TVS) was significantly higher in patients receiving tamoxifen (58.57% VS 10.71 %, P = 0.0001). Patients undergoing tamoxifen treatment had a 5.61 relative risk of developing abnormally thickened endometrium (95% CI= 2.65 -11.86).
  
  
  CONCLUSIONS
  Tamoxifen significantly increases the risk of developing abnormally thickened endometrium in postmenopausal breast cancer patients. There is, thus, a true need for gynaecologic surveillance in such patients to early detect neoplastic change of endometrium that may arise as a result of tamoxifen use.
authors.affiliation: Department of Obstetrics and Gynaecology, Faculty of Medicine, Khon Kaen University, 40002, Thailand. sisupat@kku.ac.th
authors.forename: Supat
authors.initials: S
authors.lastname: Sinawat
authors.forename: Taweesilp
authors.initials: T
authors.lastname: Chiyabutra
mesh_terms: D017677:Age Distribution; D018931:Antineoplastic Agents, Hormonal / Q000009:adverse effects* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000601:surgery; D016022:Case-Control Studies; D017024:Chemotherapy, Adjuvant; D016009:Chi-Square Distribution; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004714:Endometrial Hyperplasia / Q000139:chemically induced* / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D008991:Monitoring, Physiologic; D017698:Postmenopause; D018570:Risk Assessment; D013629:Tamoxifen / Q000009:adverse effects* / Q000627:therapeutic use; D013785:Thailand / Q000453:epidemiology
chemical_list: D018931:Antineoplastic Agents, Hormonal; D013629:Tamoxifen