Nodal volume as a prognostic factor in locally advanced head and neck cancer: Identifying candidates for elective neck dissection after chemoradiation with IGRT from a single institutional prospective series from the Indian subcontinent

Abstract

ObjectiveNodal volume as a prognostic factor has been extensively evaluated in head and neck cancer, however there is still no consensus. We attempted to analyze nodal volume as a prognostic factor in head and neck cancer treated with chemoradiation (CCRT) without an elective neck dissection with image guided intensity modulated radiotherapy (IG-IMRT). Material and methodsWe prospectively analysed 87 patients of Stage III-IV cancer of the oropharynx (57), and hypopharynx (30), who subsequently received definitive concurrent chemoradiation. Total Nodal volume (TNV) was the sum of all lymph node volumes calculated by volume algorithm from the planning CT. The impact of TNV on overall survival (OS) & regional control (RC) was assessed. Survival analysis was done using SPSS version 20.0 (SPSS, Chicago, Illinois). A receiver operating characteristics (ROC) curve analysis was done for estimation of cut offs. ResultsThe 2 year OS & RC were 64% and 83% respectively. On multivariate analysis, the TNV was a significant prognostic factor for OS &RC. ROC curve analysis found an optimal volumetric cut off of 15cc for OS & RC. The 2 year OS & RC for <15cc/>15cc group were 78% /30% (p = 0.001) & 100%/52% (p = 0.001). Similar results were obtained on subset analysis of our oropharyngeal patients with 2 year OS 75%/24% for the <15cc and >15cc group (p = 0.001). ConclusionTNV is an independent prognostic factor for OS & RC in head and neck cancer. TNV can identify patients for consideration of elective neck dissection post CCRT ie for patients with TNV > 15CC.