Cardio Oncology is a recognized field, and it sounds like you may benefit from one. My cardio oncologist looks after my heart function while urology, oncology, and radiology work on killing the cancer. He makes sure they do it without killing me. Low blood pressure is just as bad as high blood pressure except you fall down more. Urologist put me on Flomax, blood pressure tanked to below 70/50. CO said that's enough of that, figure out something else.