The simple answer is yes, but there's no simple answer of course. There are some that claim it has and I have raid personal tesemonies in books. But it would certainly depend on the extent of the cancer and how serious the damage that needs repairing also. I would imagine that curing something so serious would take an extremely lengthy fast or many long-ish fasts. Otherwise the only real way to find out is to try. If I discovered I had cancer fasting would be the healing of my choice and the very first thing I'd try.