If I had a medicial degree, opened a clinic to treat patients for cancer, and the medicine I used had no emperical evidence that it works (meaning some probabil

If I had a medicial degree, opened a clinic to treat patients for cancer, and the medicine I used had no emperical evidence that it works (meaning some probability of success determined used a properly done study) should that be acceptable? Even if I told patients I think thought the treatment would work but it's not FDA approved.