An unusual type of endometrial cancer, related to tamoxifen?

Tamoxifen, which is increasingly being used in breast cancer patients, has been associated with an elevated frequency of endometrial carcinoma. To our knowledge not a single case of uterine serous papillary carcinoma (USPC) has been documented during tamoxifen treatment. No conclusions as to a causal relationship are yet being made, but if it is due to tamoxifen, we should advise a strategy for prevention, because this subtype is not as curable as endometrioid carcinoma.