I don't understand this criticism. The comment wasn't about rejecting science. It's foolish to think that our current level of scientific knowledge is the ONLY thing worth paying any attention to.
At its extreme, this mentality can be actively harmful. I know of one person who does "spiritual healing" over the phone, charging a handsome fee to pump your telephone line full of good vibes. It may sound stupid (the cynic might even assume malice on the part of the giver-of-vibes), but things aren't so black and white when the chips are down.
[0] This wouldn't be so bad if it weren't for the fact that crazy diets compromise your ability to enjoy life without delivering any discernible medical benefit. It's all well and good to adopt a fighting attitude and say "I'm going to beat it!", but that attitude may not result in an optimal payoff in the long run.
To fight the cancer, there's not really much else. I'm a Christian and prayer is important to me. But honestly, science is the only real tool that we have to fight cancer.