Lymph node metastasis in level IIb in oropharyngeal squamous cell carcinoma: a multicentric, longitudinal, retrospective analysis

Introduction: Nowadays, 70% of patients in Europe and the USA are affected by a p16 + , potentially HPV driven oropharyngeal squamous cell carcinoma. However, despite the improved survival rate in this group, the quality-of-life remains low in cases which neck dissection took place. In this vein, in recent years, some surgeons have considered to avoid dissection of level IIB, proposing a supra-selective non-IIb neck dissection. Materials and methods: A retrospective, longitudinal, multicentric study was conducted, including patients with pathologically confirmed primary HPV + or HPV - OPSCC who went through surgical treatment for the primary lesion and neck dissection. Results: 141 patients were included. Among them, 99 (70.2%) were male and 42 (29.8%) were female. The mean age was 62 ± 9 years (range 36-81). The most frequent anatomical location was the tonsil in 63 (44.7%) of patients. The most common approach was the classic transoral oropharyngectomy in 51 (36.2%) patients. Immunohistochemistry for p16 was positive in 62 (44%) patients. One-hundred and five (74.5%) patients received a unilateral ND, and a 36 (25.5%) a bilateral ND. Of those, a 12.8% (18/141) of patients were level IIb LN + . According to our results, level IIb ND should be considered in patients underwent therapeutic ND with positive LN metastasis in level IIa (OR = 9.83; 95% CI 3.463-27.917) or III (OR = 6.25; 95% CI 2.158-18.143), advanced (T3/T4) oropharyngeal primary tumors (OR = 3.38; 95% CI 1.366-8.405), and patients with ENE (OR = 6.56; 95% CI 2.182-19.770), regardless of p16 status. Conclusions: According to our results, level IIb ND should be considered in patients who underwent therapeutic ND with positive LN metastasis in level IIa or III, advanced oropharyngeal primary tumors, and patients with ENE, independently of p16 status. Prospective data are necessary to definitively ensure the safety of omitting ipsilateral or contralateral level IIb ND in cN - patients with early stage disease.