Background: To assess the risk of subclinical neck nodal involvement of levels IB, IV and V for early T-stage, node positive, human papilloma virus (HPV)-related oropharyngeal carcinoma.
Material and methods: We retrospectively identified the patients with clinically positive and un-violated neck that underwent upfront ipsilateral neck dissection for HPV-related oropharyngeal cancer between 1998 and 2010. From the pathology report we extracted the prevalence rate of involvement of each selected level and then estimated the risk that a level that does not contain any node larger than 10 mm at computed tomography (CT) harbors subclinical disease. Predictors of involvement were investigated as well.
Results: Ninety-one patients were analyzed. The risk of subclinical disease in both levels IB and V is < 5%, while it is 6.5% (95% CI 3.1-9.9%) for level IV. Level IB subclinical involvement slightly exceeds 5% when 2 + ipsilateral levels besides IB are involved. The risk of occult disease in level IV tends to be < 5% when level III is not involved.
Conclusion: These data support the exclusion from the elective nodal volume of level V and level IB but when 2 + other levels are involved. Level IV might also be spared when level III is negative. Clinical implementation within a prospective study is justified.