I had osteoporosis 4 years prior to my cancer diagnosis, so I went on low-dose HRT, did bone-strengthening and started supplementation for osteoporosis (calcium, d3, etc.). the good news was my osteoporosis was reversed, the bad news was I had cancer (dexa & mammo on same day).
I had a post-chemo (TCHP)/post-radiation dexa and the osteoporosis is back. My oncologist didn't seem concerned when he prescribed arimidex that I already have osteoporosis, as he also prescribed Prolia (injection every 6 months) to counter it and said a dec 2015 paper came out suggesting that Prolia can also inhibit breast cancer recurrence in ER+ breast cancers. You might want to ask if that is a possibility for your tumor type and medical history. I am a strong proponent of supportive efforts like diet and bone-stregthening activities too (yoga, PT, walking). I hope you find a solution that improves your bone density.

Had reclast infusion this past Wednesday. Had severe fatigue and mild muscle spasms for 2 days - feeling. Etyerntoday but still feel tired. Hoping it helps my osteoporosis

I can't attest to Reclast but just like Triplepositive, I get a six monthly Prolia shot for my bones. Here is a useful article concerning Prolia,
http://www.breastcancer.org/research-news/proli...