Effects of hyperbaric oxygen exposure on experimental head and neck tumor growth, oxygenation, and vasculature

Background. Hyperbaric oxygen (HBO2) is used to promote healing in irradiated tissues, but concern persists about the possibility that it may promote residual tumor growth. Methods. The tumor growth of SQ20B and Detroit 562 head and neck squamous cell carcinoma xenografts were studied after single-dose irradiation and 5x/week HBO2 treatment at 2.4 atm absolute for 90 minutes. The effect of HBO2 treatment on tumor hypoxia and vasculature was also examined by immunohistochemical analysis. Results. HBO2 treatment increased tumor oxygenation during the treatment interval but did not promote the growth of either irradiated or unirradiated tumors. No increase in tumor vascular endothelial growth factor expression or vascularization was detected. Conclusions. This study found no evidence for persistent changes in tumor microenvironment or tumor growth promotion caused by hyperbaric oxygen exposure. (c) 2005 Wiley Periodicals, Inc.