What happens if my employer switched insurers when I'm in the middle of treatment?

My insurance changed mid treatment.  The hospital where I was having radiation wasn't on the plan for the new insurer, but they paid anyway after an explanation about why I needed to stay at the same hospital.  

You don't need to worry about a prexisting condition affecting your coverage as long as you stay continuously insured.  Insurance companies want to avoid a situation where people decide to save money by not being insured, and wait until a problem is diagnosed before getting insurance.

My employers change in insurers did cause me some paper work problems but no interruption in treatment.

Phyllis Johnson

JB, I suggest being proactive by getting in touch with your HR folks right away. If they don't already know, explain your situation, that your treatment CANNOT be interrupted, and that you expect them (your employer) to keep you apprised of any paperwork, etc. you might have to submit for the transition to go smoothly. And then, if things DON'T go smoothly - be camping right on HR's doorstep. It's their job to look out for you interests as an employee.