Treatment protocol
The treatment protocol in our institution for patients with NPC includes
radiation or chemoradiation therapy (CRT) according to the NCCN
guidelines. Until 2008 2D/3D -CRT was the radiation modality available
in our institution. Since 2008, intensity modulated radiation therapy
(IMRT) has been the modality of choice.
A computed tomography simulation was used to plan treatment in all
cases. Tumor volumes were outlined, and a computed tomography–based
display of the isodoses was recorded to confirm adequate target
coverage. The radiation field included the gross tumor in the
nasopharynx and neck, elective nodal stations, with a planning target
volume (PTV) of a 0.3-cm margin. In our study we examined in particular
the radiation doses of the middle ear, Eustachian tube, Levator veli
palatine and Tensor veli palatine muscles. Each radiation plan was
accessed in AriaTM radiation planning software and the
studied structures were delineated on each axial section of the
simulation imaging. Corrections were later made on the sagittal and
coronal sections of the imaging for a more precise outlining of the
structures. (Figure 1.)