Firstly, localised prostate cancer is not treated by TURP. It requires a much more major surgery in which you remove the entire prostate and part of the urinary bladder. Radiotherapy is another option which is equally good in terms of tumor control. If however, it is not localised and has spread already then the TURP is probably being done only to allow him to pass urine and not to control his disease in which case your concern of the tumor spreading becomes redundant. Either way, the TURP will do nothing to change the course of your father s disease and you should discuss treatment options for the same based on stage.