I see an endocrinologist locally and in a different medical system from my oncologist at the comprehensive cancer center. I was told by the oncologist that they treat cancer not the side effects from medications. If I have bone or menopause type issues my primary care doctor is the one who treats those. My oncologist does consider the report from my primary care doctor, and I did get a hormone therapy dose reduction based on that info.

I’m on a medicare advantage program that has paid for bisphosphonates (alendronate and Reclast/Zomata) for osteoporosis and now osteopenia.

It sounds to me like your endocrinologist is not using clinical decision making or going out of their way to get the data needed to provide better care. The endo must consider your DEXA scores, the AI med side effects, and your breast cancer history. They can’t ignore data from prior treatment. It seems like your FRAX* score along with taking an AI would put your bones at a risk level that Medicare considers as needing medication.
If your endocrinologist doesn’t know what a FRAX score is, its time to change doctors. My FRAX score was borderline, but breast cancer and family history were part of the clinical decision to treat.

Clinical considerations your doctor should consider: last bone scan score (usually DEXA, records can be transferred), family history of bone health and falls, FRAX score, current medication affecting bone health - medical research has documented the affect of AIs on bone, your age and risk of expected future bone loss, and last but not least the fact that you had breast cancer and research shows that bisphosphonates reduce the risk of cancer metastasis to the bone, that includes alendronate (inexpensive med), Reclast/Zomata infusions, and Prolia injections. Even with non invasive DCIS, like I had, a bisphosphonate lowers risk because no one knows whether I still might have a recurrence which has a 30% chance of being invasive, and is a risk for bone metastasis.

Its true that medical plans don’t like paying for the cost of infusions and the frequent Prolia injections. They often want to start with alendronate, but it is a well documented effective drug. Original Medicare does not cover outpatient prescription drugs; you need a standalone Part D plan or a Medicare Advantage Plan with drug coverage to pay for alendronate. From what I’ve read you could get generic alendronate without drug coverage and pay less than $8 a month using online CostPlus Drugs (Mark Cuban’s co.) or $11.50 using Amazon pharmacy or between $9-20 using the discounted service SingleCare or GoodRX.

Sorry this is so long, hope you can get the care you need!

*Anyone can calculate their own FRAX score using the free online tool, it is the exact same calculator your doctor uses.
https://www.fraxplus.org/calculation-tool