Effects of breathing a hyperoxic hypercapnic gas mixture on blood oxygenation and vascularity of head-and-neck tumors as measured by magnetic resonance imaging.
OBJECTIVE
For head-and-neck tumors, breathing a hyperoxic hypercapnic gas mixture and administration of nicotinamide has been shown to result in a significantly improved tumor response to accelerated radiotherapy (ARCON, Accelerated Radiotherapy with CarbOgen and Nicotinamide). This may be caused by improved tumor oxygenation, possibly mediated by vascular effects. In this study, both blood oxygenation and vascular effects of breathing a hyperoxic hypercapnic gas mixture (98% O2 + 2% CO2) were assessed by magnetic resonance imaging (MRI) in patients with head-and-neck tumors.


METHODS
Tumor vascularity and oxygenation were investigated by dynamic gadolinium contrast-enhanced MRI and blood oxygen level dependent (BOLD) MRI, respectively. Eleven patients with primary head-and-neck tumors were each measured twice; with and without breathing the hyperoxic hypercapnic gas mixture.


RESULTS
BOLD MR imaging revealed a significant increase of the MRI time constant of transverse magnetization decay (T2*) in the tumor during hypercapnic hyperoxygenation, which correlates to a decrease of the deoxyhemoglobin concentration. No changes in overall tumor vascularity were observed, as measured by the gadolinium contrast uptake rate in the tumor.


CONCLUSIONS
Breathing a hyperoxic hypercapnic gas mixture improves tumor blood oxygenation in patients with head-and-neck tumors, which may contribute to the success of the ARCON therapy.
Department of Radiology, University Medical Center Nijmegen, Nijmegen, The Netherlands. M.Rijpkema@rdiag.azn.nl
Mark
M
Rijpkema
Johannes H A M
JH
Kaanders
Frank B M
FB
Joosten
Albert J
AJ
van der Kogel
Arend
A
Heerschap
D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D005260:Female; D006258:Head and Neck Neoplasms / Q000473:pathology*; D006801:Humans; D006935:Hypercapnia / Q000097:blood*; D018496:Hyperoxia; D007822:Laryngeal Neoplasms / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000473:pathology*; D010100:Oxygen / Q000378:metabolism*
D010100:Oxygen