The data on using antioxidants with chemo show vitamin C to protect tissue that is not cancerous from radiation while not impairing the effects of radiation.
Dr. Frank Shallenberger has written a thorough protocol for using antioxidants with radiation for a much better effect.
In fact, a recent study in Cancer Treatment Reviews looked at 845 articles published on taking antioxidants such as glutathione, melatonin, vitamin A, vitamin C, N-acetylcysteine, vitamin E and ellagic acid while undergoing chemotherapy.
I think a lot of people here would be interested in taking a look at that. It's all going to boil down to the differential effects on cancer cells and healthy cells. If the healthy cells are preferentially protected from the effects of radiation or chemo, it's a win, and if the cancerous cells are preferentially protected, it's a loser. Do you have the full ref (or at least an author and a year) for that CTR review?
Here's a study that showed that vitamin C helped radiation in addressing brain cancer.
http://www.sciencedi...891584912000652