Pretreatment and prospective assessment of endometrium in menopausal women taking tamoxifen for breast cancer

OBJECTIVES: To estimate the pretreatment incidence of endometrial pathology and to prospectively assess the endometrial morbidity emerging during tamoxifen intake for breast cancer. STUDY DESIGN: One-hundred and forty-six menopausal breast cancer patients, candidate to receive tamoxifen underwent endometrial assessment by Transvaginal Ultrasonography (TU) before the start of therapy. A double-layered endometrial stripe measuring more than 4mm indicated hysteroscopy and endometrial biopsy. Endometrial abnormalities detected before the start of tamoxifen were treated by operative hysteroscopy or by hysterectomy; no therapy and yearly hysteroscopic follow-up was scheduled for patients showing non-atypical hyperplasias. All women were asked to undergo TU on a yearly basis; during the follow-up period, indication for hysteroscopy and endometrial biopsy were the following: (i) an endometrial lining measured above 4mm at the first time, (ii) at least a 50% increase of endometrial thickness since the last finding in patients previously assessed by hysteroscopy, (iii) a recorded vaginal bleeding, and (iv) previous findings of endometrial hyperplasia. Histopathologic result from biopsy or hysterectomy was the reference test to establish the baseline prevalence of endometrial pathology and the emerging prevalences of morbidity after 12, 24, 36, 48 and 60 months of tamoxifen therapy. RESULTS: One-hundred and five patients were followed for 60 months, whereas 113, 126, 137 and 141 patients were evaluated up to 48, 36, 24 and 12 months, respectively. In 44 out of 146 patients, pretreatment TU showed an endometrium thicker than 4mm and in 31 (21.2%) of these patients abnormalities consisting of 16 endometrial polyps, seven polyps harboring simple hyperplasia, four simple hyperplasias, three atypical hyperplasias and one adenocarcinoma were found. During tamoxifen intake benign endometrial abnormalities were detected in 36 out of 114 assessable patients showing normal endometrium before the start of tamoxifen therapy (31.5%) and in seven out of 27 patients with baseline endometrial abnormalities (25.9%). Overall, an endometrial pathology emerged in 30.4% of patients during tamoxifen administration and in no patients we found an atypical lesion. CONCLUSIONS: In menopausal breast cancer patients the incidence of endometrial abnormalities before the start of tamoxifen therapy is high and includes 2.7% of atypical pathology. After the diagnosis and treatment of baseline atypical lesions were accomplished, no atypical endometrial lesion emerged after the start of tamoxifen administration. Based on these findings, we believe that pretreatment assessment of endometrium is recommended in all menopausal women candidate to receive tamoxifen therapy.