IMMUNOHISTOCHEMICAL AND HYSTEROSCOPIC ASSESSMENT OF POSTMENOPAUSAL WOMEN WITH UTERINE BLEEDING WHILE TAKING TIBOLONE

The gonadomimetic steroid Tibolone, is currently widely used for the t reatment of menopausal symptoms. Up to 20% of women have been reported to have episodes of bleeding whilst on therapy. We investigated 37 ca ses who experienced bleeding episodes whilst on Tibolone and compared these to six cases who experienced no bleeding whilst on therapy and w ho underwent similar investigations in the course of a clinical study. All women underwent a diagnostic hysteroscopy and an endometrial biop sy, under a local anaesthetic. The endometrium was assessed by histolo gy and with immunohistochemical markers for cellular proliferation (Ki 67, PCNA), Heat Shock Protein 27 (HSP27) and bcl-2. There were 17 wome n with intracavitary lesions on hysteroscopy (including one in the con trol group), 10 with polyps, five with fibroids, two with congenital u terine anomalies. Histological diagnosis was not obtained in 16 cases, The high incidence of uterine polyps in the group who bled on Tibolon e suggests an etiologic relation. The staining pattern with HSP27 demo nstrated an oestrogenic effect. There were no differences in the bcl-2 immunoreactivity between those who bled and those who did not bleed o n treatment which suggests absence of a link. Similarly, there were no differences in the expression of the proliferation markers. We conclu de that episodes of bleeding in patients receiving Tibolone for hormon e replacement therapy, whilst warranting investigation, should not cau se undue concern.