The risk of level IB nodal involvement in oropharynx cancer: guidance for submandibular gland sparing irradiation

Publication date: Available online 16 February 2017
Source:Practical Radiation Oncology
Author(s): Nicholas C.J. Lee, Jacqueline R. Kelly, Henry S. Park, Wendell G. Yarbrough, Barbara A. Burtness, Zain A. Husain
PurposeXerostomia remains a common side effect of head and neck irradiation. Conflicting data exists regarding the likelihood of level IB involvement for patients with oropharyngeal squamous cell cancer (OPSCC), and limited data has examined this risk in patients with HPV-positive (HPV+) disease. This study examined surgically-treated OPSCC in order to determine the risk of pathologic level IB nodal involvement and to identify a cohort of patients in whom ipsilateral level IB radiotherapy may be safely omitted.Methods and Materials102 submandibular nodal dissections were identified (92 ipsilateral and 10 contralateral) in 92 patients from 2010–2016 in patients undergoing primary surgical treatment and dissection of ipsilateral level IB lymph nodes. Radiographically positive cases were excluded. Retrospective chart review was used for data collection, and the rate of pathologic level IB involvement was determined.ResultsThe ipsilateral level IB nodal station had negative imaging and pathologically positive nodes at rates of 4.3% in OPSCC and 5.3% in HPV+ OPSCC. Positive node burden in the ipsilateral neck at stations other than IB appeared to correlate with the risk of pathologic positive IB (pIB+) nodes: 50% of pathologically IB-negative patients had 2 or more positive nodes versus 75% of pIB+ patients had 4 or more positive nodes.ConclusionsOur data indicates a low risk of pathologic level IB involvement in early-stageOPSCC. High positive node burden in stations near level IB may be associated with a higher chance of pathologic level IB involvement.



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