Dear @zara_xo, I am a 67 year old woman who was prescribed Letrozole. I took it for 11 months but came off it because it caused me to develop another fibroid ( I already had an 8cm Fibroid prior to cancer diagnosis) and, alarmingly I also developed an ovarian cyst described as an endometrioma indicating the presence of endometriosis. I am now under the gynaecology dept for quarterly surveillance. When I discussed my situation with the gynaecologist, in particular the possibility of swapping to a different type of hormone therapy, his advice was that if I did so then Tamoxifen should be right at the bottom of any list due to its tendancy to cause polyps.