OP126: Planned neck dissection in oropharyngeal cancer

Abstract

Today concurrent chemoradiotherapy (CRT) is the current standard of care in the non surgical management of locally advanced (N2–N3) oropharyngeal squamous cell carcinoma providing excellent locoregional control and overall survival. The necessity for postchemoradiation planned neck dissection (PND) after a complete locoregional response, especially with advanced pretreatment nodal disease ( N > 3 cm), remains controversial. Some Authors still perform planned neck dissection, others have adopted a watchful waiting approach in an effort to avoid neck dissection and its complications in a newly irradiated surgical field. The purpose of our observational study was to determine the ability of neck US, MRI and FDG-PET in detecting residual cervical metastases after concomitant chemoradiotherapy in patients with advanced neck disease. 31 previously untreated patients with locoregional advanced ( N > 3 cm) oropharyngeal squamous cell carcinoma were enrolled. All patients were treated with radical chemoradiation therapy with curative intent. Twelve weeks after completion of chemoradiotherapy all patients were re-evaluated by neck US, MRI and FDG-PET to assess clinical and radiological response or progression of disease. If the primary site was clear of disease regardless radiological response to the treatment on the neck, the patients underwent PND. The sensitivity, specificity and diagnostic accuracy of neck US were 90%, 72.7% and 81% respectively. The sensitivity, specificity and diagnostic accuracy of MRI were 80%, 54,5%, and 66,7% respectively. The sensitivity, specificity and diagnostic accuracy of PET were 40%, 90,9%, and 66,7% respectively. Complications rate was high in patients who underwent PND (40.6%) especially when a RND or MRND was performed. Based on this preliminary analysis we suggest that patients with no clinical residual disease in the neck and negative MRI, US and PET 12 weeks after definitive chemoradiation therapy are highly reliable for the absence of residual cervical nodal disease and can be safely observed avoiding neck dissection and its complications. In patients with clinical residual nodal disease in the neck and metabolically inactive radiological pattern (negative PET, no contrast enhancement and low signal in T2 and fat suppressed sequencies at MRI and no vascularization at US ) 12 weeks after chemioradiation therapy selective neck dissection is safe and feasible.