Tamoxifen and endometrial cancer. Is screening necessary? A review of the literature.

Tamoxifen is a selective oestrogen receptor modulator (SERM) with anti-oestrogenic activity in the breast and oestrogenic effects in various tissues such as the endometrium, bone and cardiovascular territory. As adjuvant hormone therapy, it has a clear beneficial effect in patients with breast cancer, reducing relapses, contralateral breast cancer and mortality. Its most important secondary effect is a greater rate of occurrence of endometrial cancer. Although the risk/benefit ratio is clearly positive, the follow-up on these patients is still an issue. In women with metrorrhagia, it is clear that an endometrial sample must be obtained for histological examination and the best procedure today is hysteroscopic-directed biopsy. Nevertheless, the need to screen asymptomatic patients is not universally accepted. The vaginal ultrasound scan gives a great number of false positives. This entails more aggressive and more expensive procedures such as hysteroscopic-directed biopsy, meaning greater expense and more complications. As a result, the cost/benefit ratio is not very favourable. The rate of occurrence of endometrial cancer in 1026 tamoxifen-treated patients with breast cancer in our hospital between 1999 and 2001 was 1.25%. Two cases were diagnosed in asymptomatic patients. In this article, we analyse the literature on the need to screen patients on tamoxifen and about the most appropriate diagnostic protocol.