Induction (neo-adjuvant) chemotherapy: systemic and arterial delivery techniques and their clinical applications

Induction chemotherapy is a well tried method of improving the cure prospects of locally advanced or aggressive primary cancers. It is most simply administered by systemic (intravenous) delivery but for some cases a greater chemotherapy impact is both desirable and achievable with the use of a more concentrated regional delivery technique. Any advantage of regional chemotherapy will depend upon the type of tumour to be treated, its site and blood supply, the most effective doses, concentrations and exposure periods of the preferred agents to be used and the relative risks of systemic and regional toxicity and the techniques of delivery. In general, systemic chemotherapy is most appropriate in treating tumours without a single artery of supply; when certain agents which are inactive until modified in body tissues (such as cyclophosphamide or DTIC) are to be used; when satisfactory responses can be achieved more easily by systemic delivery; when technical skills and facilities for regional delivery are not available; or when the patient's general health, co-operation or long-term prognosis precludes the additional complexity of regional delivery. Intra-arterial infusion may have advantages in treating head and neck, gastric, liver, some locally advanced breast, limb, pelvic and possibly pancreatic malignancies. More complex techniques to achieve short-term highly concentrated chemotherapy include closed circuit perfusion; chemofiltration infusion and 'stop flow' perfusion; and regional limb infusion. These should remain the subject of ongoing studies in highly specialized units which treat tumours such as melanoma or pancreatic cancer which respond poorly to lower chemotherapy concentrations.