You are right, there needs be balance. A complete view of all nutrient levels, as well as tests for heavy metals or toxins need be done. This gives you a good base line; and it points out what is out of balance and the detoxing levels needed.
A full rounded treatment protocol is necessary to achieve resolution of the cancer. If you have used chemo or radiation you have to take this toxic treatment against the body into consideration when you set up a protocol. Vitamin C is an excellent component in the protocol, curcumin is another excellent adjunct therapy; hyperthermia is excellent in weakening the cancerous tumors; adding stronger treatments like BX Antitoxin is a good option to attack the cancer. Above all, you have to treat the person as a whole - address the cause and treat the symptoms, then rebuild. jesichashope.org has a good explanation on most of these options to educate yourself on.