Method of administration of chemotherapy to tumors

Abstract

An improved method of administration of microspheres of cytotoxic chemicals to tumor sites without effect on non tumor tissue is disclosed. The method comprises injection of chemotherapeutic agents coated with a thermoplastic polymer having a melting point above normal body temperature (in a melting point range of about 40.degree.-46.degree. C.) accompanied by dielectric radio-frequency localized heating of the tumor to elevate its interior temperature above the melting point of the encapsulating thermoplastic polymer. The tumor is partially necrosed and sensitized by the R.F. nonionizing radiation bombardment and the entry of the chemotherapy agent triggered by the removal of the protective coat of thermoplastic polymer. A preferred embodiment of the invention is a dose of 30 mg of methotrexate (A-methopterin) in the form of spherical microscapsules having an average of 200-800 microns diameter and a polymer of polystearyl acrylate encapsulating coating of an average thickness of 1-50 microns. This dose is injected into the tumor and released by a 30-60 minute irradiation of the tumor by 175-200 watts of R.F. non-ionizing radiation at a frequency of 13.56 megahertz from a set of capacitive plates positioned on opposite sides of the impregnated tumors. The tumor temperature is elevated to a threshold temperature of 43.degree. C. which is the melting point and release point of the encapsulated acrylic resin. The temperature of the rest of the organism outside the tumor remains at 39.degree.-40.degree. C. which is below the release temperature of the resin.