Yes, Nelie is right, beta-carotene (in the NCI trial) caused more cancer in smokers. But there is enough additional evidence of harm that the Dr. Charles Myers, a top medical oncologist dealing with prostate cancer, strongly advises his patients not to take it. I will go through his Forum newsletters (but not tonight) and get the references -- all his recommendations pro and con are based on clinical studies, not anecdote.

The reason cancer cells are more vulnerable to radiation is that they do not function normally or efficiently to heal DNA damage -- the latter enhanced by free radicals, thus the advice to avoid chemicals which (in turn) might scavenge these free radicals and "protect" the cancer cells. However free radicals can also cause normal cells to become abnormal, by damaging their DNA.

In other words, not a real simple picture!

There are studies which have shown significantly decreased mucositis in patients treated with topical Vitamin E (but not ingested) and also, vitamin E is part of a trial which has found a much improved survival and reduced recurrence in HNC patients treated post-radiation with interferon, retinoin (a form of vitamin A ) and plain old alpha-tocopherol (Seixas-Silva et al, 2005, Arch. Otolar. Head Neck Surgery 131 (4). But this is post-treatment.

Gail Mackiernan