The Risk of Hair Dye

I don't know why I was surprised when I first read about hair dye possibly increasing the risk of certain cancers, including follicular non-hodgkins lymphoma. Chemicals being applied to the skin, ofcourse there would be risks. So now my question is, does dying my hair increase my chances of the cancer spreading or growing since I already have FNHL. The answer I would assume could be yes. I suppose that means I may be sporting some grey hairs soon. Unless I can find a healthier alternative. Here is an article about it.
If anyone has experience with natural hair dyes, such as henna. Please let me know about your experience with it. Here is one place that claims to sell natural hair dye. I may give it a try.