418 Direct intratumoral injection of colloidal 32P in addition to conventional radiotherapy for advanced head and neck cancer: A pilot study

Abstract

A new technique of infusional brachytherapy, developed by Order, using macroaggregated albumin followed by chromic phosphate ³²P, allows the selective irradiation of the tumor at very high doses. In order to improve the treatment of locally advanced unresectable or recurrent head and neck cancer, this technique was studied to deliver a continuous extra radiation dose to the tumor, in addition to conventional fractionated radiotherapy. Nine patients were included in the study. Bremsstrahlung imaging, performed for direct tumor quantification and dosimetry, showed the ³²P activity at the injection sites, up to 70 days post-injection ³²P activity was found to be insignificant in the blood (<0.00001%ID/ml) as well as in the saliva (<0.001%ID/ml). Except for facial edema in 2 patients, regressing with corticosteroids administration, no acute treatment-related, hematological or mucosal, toxicity was observed. Significant tumor regression was noted for three out of five patients evaluable, treated by combined intratumoral colloidal ³²P infusion and external irradiation. Thus, this technique of infusional brachytherapy by colloidal ³²P may be a valuable adjunct to conventional radiotherapy to boost the dose in locally advanced head and neck cancer. Our phase I/II study is currently in progress.