Ooooh that is a difficult situation! Now that the tumour has shrunk with her change of diet and supplements (and good attitude/energy probably, too) - why don't they think that she can continue to shrink it until it dissolves by doing what she's been doing? Frustrating to not have support in that realm. It seems logical that she is doing all the right things...and getting results.
Your wife, of course, is going to have to go with her intuition. It's her choice...either way. Whatever she chooses will be right. She has to trust that.
Have you read any of the articles on The Doctor Within? www.thedoctorwithin.com . There is one article titled: For the Cancer Patient. Get her to read it. Also, 'Journey to the Center of the Colon' and 'Last Resort'. It explains how when the body is filled with too many toxins...the toxins spread to the weakest organ (each person has their weakness)...and by doing what your wife is doing, eating raw vital organic foods (enzymes! Vitality!), drinking pure water, sunshine, laughter...by doing things like this the body will heal itself.
Dr. Schulze says some interesting things about disease and cures too. //www.curezone.org/schulze/handbook/TNIP.asp . He sites his own bought with heart disease when he was a teenager. He was told he wouldn't live beyond x amount of years. He began to study herbs and eat lots of vegetables and foods that were still alive. He is alive and well today...but when asked if he 'cured' himself he is not so sure. He feels like he'll probably always have a weak heart - and if he went back to eating the toxic food (non food is what is served up in those boxes in our grocery stores!) that he was eating before - he would probably have heart disease again. So...eating well, living well, breathing well, drinking pure water....it's an on-going thing...if one should be Healthy and keep their Body happy.
Mind, Body and Spirit should be kept in balance, too.
Well...I am rambling, I know!
Whatever your wife decides...I'm sending healing energy to her!