Clear Cell Endometrial Cancer + ATM gene mutation

I was just diagnosed with CCEC from a biopsy and still have a CT scan to determine next steps. I've been reading a lot about this aggressive cancer and various treatments. I'm wondering if anyone has the genetic mutation of the ATM protein as well. Since it's a repair gene mutation, I'm not supposed to be exposed to radiation. But that seems to be a critical part of the CCEC treatment.