<s>[INST] Hi: My name is Mary and in November, 2012 I experienced a pain/cramping in my lower left abdomen . It lasted probably a day and a half, then nothing. I made a Dr. appointment, and he prescribed an ultrasound . I didn t get in for my ultrasound until late January, 2013, and the results of the ultrasound was- thickening of the uterin wall. My Dr. then made an appointment with a Gynocologist , which was for today, however, due to a very stormy day, she cancelled. I have to call her office tomorrow to re-schedule an appointment. Last January, I had a lumpectomy performed on my left breast, went through radiation , however opted out of chemo , but I am taking a daily pill - Letrozole -for 5 years. March 1,2013 will be the start of my second year on this pill. Naturally I am concerned, and even more concerned now that the appointment was cancelled, like could it be cancer??? My friend had a similar thickening of the uterin wall quite a few years ago and she was given pills to try to thin it and then had an ablaision(spelling?) procedure done. My mind tends to runneth over. Your input into this will be much appreciated. Thanks. [/INST] Hi, Hormonal agents used in breast cancer has a tendency to cause endometrial hyperplasia ( uterus wall thickening). But that is more frequent in tamoxifen not in letrozole. Anyway a biopsy from proliferative uterus wall is necessary , there may be other non cancerus causes also, so nothing to worry at present, consult your gynaecologist. </s>