Progress review: intrathecal and intratumoral injection of radiolabelled monoclonal antibodies (MoAbs) for the treatment of central nervous system (CNS) malignancies.

The systemic administration of monoclonal antibodies (MoAbs) as delivery vehicles for targeted radiation therapy is associated with many problems. Most studies show that insufficient isotope is taken up into the tumour to elicit a tumoricidal effect. This has led several groups to explore the administration of radiolabelled MoAbs into body compartments, specifically for the treatment of minimal tumour deposits that present either as malignant ascites or small nodules on the lining of body cavities. The use of 131Iodine (131I) labelled MoAbs in the treatment of disseminated disease in the central nervous system (CNS) is described and the possibility of administering radiolabelled MoAbs to a cavity generated after debulking surgery for malignant glioma in order to overcome the problem of poor MoAb uptake into solid tumour deposits is discussed together with the rationale for substituting 90Yttrium (90Y) for 131I.