There is a difficulty here in that there are many different definitions of 'complementary' and 'alternative' therapies. The American Cancer Society has, however, suggested that alternative therapy is the use of unproven, or disproven, ways of preventing, detecting or treating cancer. By contrast they define complementary therapies as supportive methods used to support conventional treatment by controlling symptoms and improving quality of life.

Using these definitions alternative therapies for cancer are often promoted by their supporters as treatments to be used instead of the normal treatments of either surgery, radiotherapy or chemotherapy. By contrast, supporters of complementary therapies say that they should be used alongside the usual treatments and by so doing they will improve the well being of the patient.

In recent years there has been an increasing use of the term 'integrated medicine' to cover the bringing together of complementary and conventional therapies for the care of individual patients.

Certainly there is growing support among doctors and nurses for complementary therapies which, although they do not influence the cancer itself, can make people who have cancer feel more comfortable and contented. In general, however, health professionals remain very much against alternative therapies, where treatments of no proven value are recommended to patients instead of the normal treatments which have been scientifically tested and shown to be of benefit.