Endometrial evaluation prior to tamoxifen: preliminary results of a prospective study

The objective of this study was to try to identify by pretreatment screening, a group of patients at higher risk of developing endometrial carcinoma on tamoxifen. Between January 1993 and January 1997, 360 postmenopausal patients with breast cancer were enrolled in this prospective study. Basal screening included gynaecologic examination with a Papanicolaou smear and endovaginal sonography. In the case of an abnormal ultrasound (endometrial thickness greater than 4 mm), an outpatient hysteroscopy with an endometrial biopsy was carried out. There examinations were repeated annually. By means oft his preliminary evaluation, two groups of patients were identified: patients without initial lesions (group I) and patients with initial endometrial lesions (group II). These two groups of patients were followed up separately exactly in the same way. Endometrial lesions taken into account were: adenocarcinomas (in situ and invasive), polyps with or without atypia, myomas and adenomyotic lesions with irregular mucosa. After 3 years and after 4 years of follow-up, the percentage of atypical lesions was significantly higher in the group with initial lesions than in the group without initial lesions. This study suggests that a group of high risk patients more sensitive to the carcinogenic effect of tamoxifen can be identified by pretreatment evaluation.