Fasting, such as is called for in the Brandt grape cure, is a good way to both rid the body of toxins and waste while also striking at the cancer.
Many people successfully beat cancer without fasting, but I personally would begin with a few days or so of something like the Brandt cure and then begin to incorporate a healthy Diet and many other elements (for more detail, take a look at my post here "Modern Medicine versus Nature in Treating Cancer")