Milk Thistle

According to the NCI (National Cancer Institute), milk thistle is ineffective and like all of their recommended complementary and alternative treatments, it is not FDA approved. The alternative cures listed on the site offer little hope and are backed with little scientific evidence. If I were you, I would look at other sources.

I do have a helpful recommendation for you however that does have a lot of scientific proof to back it up. Adopting a macrobiotic diet/lifestyle has been proven to cure many people of cancer. Specifically for leukemia, a diet consisting of 50-60 percent of whole grains, 5-10 percent soups, 20-30 percent of vegetables, 5 percent beans, and roughly 5 percent of sea vegetables is recommended. The specific information about the causes and macrobiotic cures for leukemia can be found in The Cancer Prevention Diet by Michio Kushi. Not only does he write about the causes and cures of leukemia (as well as roughly 25 other cancers), he also has scientific studies to back up his claims and testimonies from people who have recovered from each type of cancer by adopting a macrobiotic lifestyle. Christine Perillo is a woman who cured herself of leukemia by adopting this diet, and her testimony is in the book as well as on youtube. If you type in "diet saves their lives vol. 14", you will be able to hear her story. It is only 8 minutes and thirty seconds long.....why not check it out? Also, if this interests you, of course a consultation with your doctors would be a good idea to make sure that this wouldn't interact badly with your treatment.
If your interested, I could give you a list of books that might be helpful. I would be happy to answer any questions you might have, although a macrobiotic counselor would be better equipped to answer your questions than I am.

Hope this is helpful!