A patient checks into the hospital for a routine procedure to treat an enlarged prostate. And, unexpectedly, a test done in the hospital — perhaps a blood test or an X-ray or an examination of the urethra and the bladder — finds a cancer. Apparently, something like that happened to King Charles III. When the British monarch was treated for an enlarged prostate in January, doctors found a cancer that the palace said is not prostate cancer. Charles started treatment Monday. The palace did not disc