Role of Carbogen in the Treatment of Head and Neck Cancer.

trolled neoplastic cell proliferation, solid tumor masses typically exhibit abnormal blood vessel networks that fail to provide adequate and homogeneous nutritional support to the tumor cells. Such spatial and temporal heterogeneity of the microcirculation within a tumor can result in an expansion of intercapillary space and a decrease in vessel density. These factors may consequently lead to increased oxygen-diffusion distances and oxygendeficient or hypoxic regions in tumors. Areas of low oxygen tensions (pO2) have been well documented using oxygen electrodes in both rodent and human tumors. Most critically, pO2 distributions measured in malignancies generally have been found to be far lower than those in the surrounding normal tissues.