Modulation of tumor oxygenation and radiosensitivity by a perfluorooctylbromide emulsion

The effect of a concentrated perfluorooctylbromide emulsion (Oxygent) on the radiosensitivity and oxygenation of solid tumors was examined using EMT6 mammary tumors in BALB/c mice and BA1112 rhabdomyosarcomas in WAG/rij rats. Treatment with Oxygent plus carbogen or oxygen breathing increased the radiosensitivity of both tumors. Analysis of tumor cell survival data and polarographic measurements of intratumoral pO2 indicated that this potentiation reflected an increase in the proportion of well-oxygenated tumor cells. Treatments with carbogen breathing alone, with Oxygent plus air-breathing, or with a vehicle emulsion containing all the components except the perfluorocarbon did not produce comparable improvements in tumor radiosensitivity. Concentrated perfluorooctylbromide emulsions appear to warrant further development and preclinical testing as adjuncts to cancer therapy.