Dexascans--how often; Fosamax---when

I was also diagnosed in 2013, but at the age of 67. My oncologist wanted a bone scan before putting me on hormonals and I already had osteoporosis. I get DEXA scans every other year. Fosamax took my femoral head reading from -3.1 to -1.7 in two years. I'm still not on the homonals though. Maybe after the next scan. As far as I know, the protocol hasn't changed, at least according to my oncologist.

My doc is holding off on the bone drugs for now, although I am right on the border to osteoporosis. He says I will probably have to take something eventually, and that when I do, he would prefer prolia. For now, he figures that I am otherwise fit and healthy, so my fracture risk is low

Every other year is standard for DEXA scans, and is what Medicare pays for. I would definitely not want to extend that period for anyone on a drug that affects bone density, or anyone already osteopenic. You are both, and, like me, are on not one, but two such drugs. Ixnay on the three years. I'm only osteopenic but am on a bisphosphonate because my single pre-arimidex drug created a definite downward slide in my bone density. To tell the truth, I'd worry that a doc who suggested a lesser schedule might be under pressure to keep costs down.

My understanding is that the recommended interval in every two years. Like someone else said, I'm surprised the new PCP suggested waiting longer, since you're taking two drugs that can contribute to bone loss.

Have you considered talking to a bone specialist? Endocrinologists usually know more about bones than PCPs. Many treat a range of health concerns, like diabetes, and if you ask around, you might find someone who specializes about bone health. I've had consultations with the former head of the UCSF osteoporosis clinic. (FWIW, he recommends DEXA every two years).