The Frequency of Lymph Node Metastases by Neck Level in p16 Positive
Oropharyngeal Squamous Cell Carcinoma
Abstract
Objectives To determine the frequency by neck level of clinically known
and occult lymph node metastasis in p16 positive oropharyngeal squamous
cell carcinoma (p16+ve OPSCC). Design Retrospective study of 61 patients
with p16+ve OPSCC whom had neck dissection and prior or simultaneous
trans-oral surgery. Histopathology reports of neck dissection specimens
were compared to preoperative clinical and radiological reports to
determine the distribution of clinically known and occult nodal disease
at each neck level and its concordance with preoperative findings.
Positive and negative predictive values for pathological nodal disease
(pN+ve or pN0) were assigned to clinically assessed node-positive
(cN+ve) or node-negative (cN0) status at each neck level. Setting Single
tertiary referral centre in the UK Participants 61 patients with p16+ve
OPSCC with no prior head and neck cancer treatment. Main outcome
measures Clinical, radiological, and pathological findings of nodal
disease in the neck. Results Two-hundred individual neck level specimens
were analysed. Seventy-seven levels were considered cN+ve, of which
83.1% (64/77) were also pN+ve. One hundred and twenty-three levels were
considered cN0 of which 13% (16/123) were proven as pN+ve,
demonstrating occult disease across various levels. This occult disease
was identified in level II in 7 patients, level III in 6 patients and
level IV in 3 patients, with no occult disease seen in cN0 level I or V.
Conclusions These findings augment existing limited data on the
distribution of occult nodes in OPSCC specific to p16+ve disease and
reaffirm the rationale for dissecting at least levels II-IV in any cN0
neck.