Abstract
In recent years, the importance of chemoradiotherapy (CRT) for the purpose of organ preservation in the treatment of laryngopharyngeal cancer has increased. In conducting a prospective study about post CRT neck dissection, it is difficult to plan a study on a detailed treatment regimen because of the variability of CRT regimen performed in each institution. Therefore, we conducted a study on imaging criteria used when determining the necessity of neck dissection after CRT. A prospective study was conducted on “examination about neck dissection after chemoradiotherapy” to confirm the accuracy of imaging as a feasibility study.
Oropharyngeal, hypopharyngeal and supraglottic laryngeal cancer patients administered with platinum-based chemoradiotherapy were eligible. An imaging examination by CT (and/or MRI, if possible US) was performed 4-6 weeks after completion of CRT (first evaluation), while a PET-CT was performed 8-12 weeks after completion (second evaluation). The necessity of neck dissection was evaluated by the imaging.
Accuracy of the imaging (CT/MRI) at the first evaluation was 60%, while the negative predictive value was 77%. At the same time, accuracy of the general diagnosis by physicians was 83%, while the negative predictive value was 92%. The accuracy rate of the second evaluation by PET-CT was 93%, while the negative predictive value was 92%.
The protocol of diagnostic imaging for this examination was permitted by hypothesis testing, but further improvement is necessary. Addition of US diagnosis may lead to improved accuracy at first judgment. It should thus be further examined.
