EFFECTS OF HYPERBARIC OXYGEN EXPOSURE ON EXPERIMENTAL HEAD AND NECK TUMOR GROWTH, OXYGENATION, AND VASCULATURE

Abstract: Background. Hyperbaric oxygen (HBO2) is usedto promote healing in irradiated tissues, but concern persistsabout the possibility that it may promote residual tumor growth.Methods. The tumor growth of SQ20B and Detroit 562head and neck squamous cell carcinoma xenografts werestudied after single-dose irradiation and 5 /week HBO2 treat ment at 2.4 atm absolute for 90 minutes. The effect of HBO2treatment on tumor hypoxia and vasculature was also exam ined by immunohistochemical analysis.Results. HBO2 treatment increased tumor oxygenationduring the treatment interval but did not promote the growthof either irradiated or unirradiated tumors. No increase in tumorvascular endothelial growth factor expression or vascularizationwas detected.Conclusions. This study found no evidence for persistentchanges in tumor microenvironment or tumor growth promotioncaused by hyperbaric oxygen exposure. A 2005 Wiley Period icals, Inc. Head Neck 27: 362 – 369, 200