Why Is Prolia Prescribed In A Person With Breast Cancer?

My oncologist has me taking Prolia but I have never been told I have osteoporosis. I had breast cancer 2 yrs ago and have done well so far but I don t know why I need to take this and I m reading a lot of negative side effects can happen. Also, I don t believe I m in the high-risk population to get osteoporosis. I am 5 10 weighing 230 pounds and at age 68 I now have had 4 joint replacements over the last 8 years.