Chemotherapy Chemicals and Cancer

I know that chemotherapy uses chemicals to treat cancer, but don't certain chemicals also start cancer? Is chemotherapy a situation where we fight fire with fire?

[seattlemom2plus]

It's certainly a hard question to answer, as I certainly am one for natural treatments as much as possible.  I even find the studies with camel milk and cancer to be of a strong intrigue.

But on the other spectrum, my grandmother had chemo 3 times in her life for colon cancer, breast cancer, and lung cancer and she has added literally 15 years onto her life.