Here’s the real problem, IMO. Transplant patients are put on drugs to suppress the immune system. I knew of a heart transplant young man (son of a co-worker) who died a few years later of cancer because of the immunosuppressants. That probably has a lot to do with this man’s cancer growing.
Good point re the effect of immuno-suppressants on the transplant patient and IMO another argument against a verdict of malpractice in such cases.