at this point i do not believe there is a law or policy at this time (after researching, perhaps someone else has run across this) it seems to depend on patient policy, some insurances require a pre authorization and i found many other's don't require this when the patient is going in for a mastectomy for breast cancer other breast. i use V50.41 as primary diagnosis and then the breast cancer diagnosis as secondary. so far no claims have been denied. hope this helped some if any.