Yes, that's true, but it's apparently quite rare. My two cousins have been taking Tamoxifen for many years and have had no problems. It seems like they all have downsides. The Arimidex can cause heart problems among other things for instance. I've started taking that, but only for Monday, Wednesday and Friday. I will do that for about a month or two to see if I can tolerate it. Then if I find I'm doing ok, I can add the additional two days and take the weekend off, like you do with the radiation treatment. Some doctor on the panel did recommend that for when you start taking it. So, I'm giving it a chance. However, I still have to have the DEXA scan to see how my fairly old bones (I'm 79) are doing? Good luck on your journey - keep your spirits up!