Tamoxifen and risk of endometrial cancer

"Dr. Albain said the reason the abnormality rate was much lower than expected most likely was due to the study's screening requirements. All women recruited for the study underwent uterine ultrasound exams before taking tamoxifen. If the ultrasounds showed a thickening of the inner lining of the uterus greater than 5 mm, a biopsy was performed. If the biopsy showed an endometrial abnormality, the woman was excluded from the study."

This quote from the article stood out, for me anyway.