Selective omission of level V nodal coverage for patients with oropharyngeal cancer: Clinical validation of intensity-modulated radiotherapy experience and dosimetric significance.

Background: We sought to validate the consensus recommendation and assess dosimetric significance of selective omission of nodal level V from intensity-modulated radiotherapy (IMRT) clinical target volume (CTV) for oropharyngeal cancer.

Methods: IMRT plans and clinical outcomes for 112 patients with oropharyngeal cancer (nodal classification N0-N2b) were analyzed for coverage of ipsilateral and contralateral nodal level V. Additionally, new IMRT plans were generated in 6 randomly selected patients to assess its dosimetric impact.

Results: With median follow-up of 3.4 years, there were no failures identified in nodal level V with or without nodal level V omission. Upon dosimetric evaluation, significant reduction in integral dose, V10 Gy , V20 Gy , V30 Gy , V40 Gy , and V50 Gy was observed by excluding unilateral and bilateral level V from the CTV.

Conclusion: We clinically validate the consensus recommendation for selective omission of level V nodal coverage in IMRT planning of patients with oropharyngeal cancer and demonstrate significant dosimetric advantages.