Some anti-cancer drugs are adequate in themselves to treat a particular cancer, but most of them are not. Since various drugs act differently, it was considered that a combination of them, each acting differently, would have a synergistic or increased effect. Dramatic results were produced by treating lymphomas or tumour of lymph node in this way.
The four drug combination of Nitrogen mustard, Vincristine, Procarbazine and Prednisolone yielded complete remission in more than 80 per cent of patients with advanced Hodgkin’s disease, whereas these same drugs used singly rarely produced remissions or lessening of symptoms in 15 to 20 per cent of cases. Similarly, combination chemotherapy for acute leukaemia or blood cancer increased the remission rates from 20 to 90 per cent.
Not only are different anti-cancer drugs used in combination to achieve better results, they are also used along with surgery and radiation.
Over the past 20 years, it has been shown that combination chemotherapy is valuable in many other cancers including cancer of the breast, ovary, lungs, testes and several of the childhood cancers.
With the development of combination chemotherapy, it became clear that the clinical course of different types of cancers could be influenced by cytotoxic drugs with cure in some and useful palliation-, i.e. which gives temporary relief from the symptoms—in many others.
It is possible to rank many kinds of cancers into different groups comprising those, for which chemotherapy contributes to cure, those for which effective control prolongs precious life, and those for which benefit is less certain or unproven.