Prevalence of Level IB Metastasis in Surgically-Treated p16+ Oropharyngeal Squamous Cell Carcinoma.

BACKGROUND

Surgical management of oropharyngeal p16 positive squamous cell carcinoma (p16+ OPSCC) often includes neck dissection, however the prevalence of level IB metastasis is not widely reported. Our study aims to determine the prevalence of level IB nodal metastasis in p16+ OPSCC to help determine if level IB should routinely be included in neck dissection.

METHODS

We assessed a 102 patient cohort of surgically treated p16+ OPSCC to determine the prevalence of level IB metastasis among patients that underwent neck dissection and TORS.

RESULTS

One hundred two patients (105 necks) underwent TORS neck dissection. A 52.9% (n = 54) of patients presented with T1 tumors and 39.2% (n = 40) of patients presented with T2 disease. Perineural invasion was noted in 12.7% (n = 13) of patients, while lymphovascular invasion was noted in 26.5% (n = 27) of patients. Extranodal extension was noted in 41.2% (n = 42) of neck dissection specimens. The average number of nodes dissected per neck was 35.1 (SD = 12.9). Metastasis to cervical lymph nodes was noted in 91 patients (89.2%). Level IIA was most frequently affected (n = 85, 93.4%), followed by level III (n = 29, 31.9%) and level IIB (n = 15, 16.5%). Metastasis to level IB was noted in 3 patients out of 102 that underwent dissection of level IB (2.9%). No patients in this cohort were found to have metastasis to levels V or VI. Nine patients (8.8%) were found to have recurrence of any kind. Of those that did have recurrence of disease, 2 were classified as local, 3 (2.9%) classified as regional, and 4 (3.9%) classified as distant.

CONCLUSION

Our results indicate a low burden of metastatic disease in the level IB nodal basin concordant with results reported by other institutions. We argue that the level IB nodal basin should not be routinely included in neck dissection for p16+ OPSCC.