Patient and tumor characteristics.

aPCR on DNA was performed, using the primers listed in [9]. The products were detected by polyacrylamide gel electrophoresis or the Agilent DNA 1000 kit (Agilent Technologies Inc., Germany). bHPV status was not determined for one patient in the basic cohort due to lack of DNA for analysis. cTumor size and lymph node status were determined from pretreatment magnetic resonance (MR) images. dVolume was calculated based on 3 orthogonal diameters (a,b,c) as (π/6)*abc. eDiameter was calculated from tumor volume (4π/3)*r3.