My best friend did Gerson therapy. (Google it). She had melanoma at 25 which came back at 31ish. Viciously. Surgery wasn't an option. A very high protocol of immunotherapy type treatment was one option. Juices/Gerson therapy was another. one was going to make her very sick immediately. The other. . Gerson... wouldn't. They (her and her DH) knew that she didn't have a lot of chance with anything. Sadly. She lived in new York at the time. I spent a month pretty much following the Gerson therapy and making her the food and juices because that's what she wished. I didn't really believe in it.
Sadly she passed away.
I think these juice therapy things can help make you feel better. .. but shouldn't take the place of proven medicine. In my BFs case. .. she was given a terminal prognosis.