There is clear evidence that extended adjuvant tamoxifen therapy for 10 years reduces local recurrence and improves breast cancer-free survival in women with oestrogen receptor-positive breast cancer. An analysis of large randomized controlled trials, however, reveals that extended use is linked with a two-fold increased risk of developing endometrial (womb) cancer, when compared with standard 5 years of tamoxifen.
While more research is needed, the BJS (British Journal of Surgery) findings suggest that screening for endometrial cancer may be warranted in patients who receive extended tamoxifen therapy.
"There is a paucity of clear evidence on how we should best manage endometrial cancer risk in extended tamoxifen therapy. This is a research area that requires immediate focus with expansion of extended tamoxifen therapy regimes," said lead author Dr. Christina Fleming, of St. Vincent's Hospital Group, in Dublin, Ireland.
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C. A. Fleming et al, Meta-analysis of the cumulative risk of endometrial malignancy and systematic review of endometrial surveillance in extended tamoxifen therapy, British Journal of Surgery (2018). DOI: 10.1002/bjs.10899