Predictive value of sentinel node biopsy in head and neck cancer

Abstract

Conclusions: The negative predictive value (NPV) of sentinel lymph node biopsy (SNB) in this study was 95%. The accuracy of SNB compared to histopathologic evaluation of surgical specimen of subsequent neck dissection (ND) was 96%.

Objective: To evaluate NPV of SNB in head and neck cancer.

Patients and methods: This was a prospective clinical study comprising 35 patients (50 necks) with squamous cell carcinoma (SCC) of head and neck with clinically (cN0) and radiologically negative necks, without previous treatment, who underwent SNB with gamma probe and subsequent ND. The NPV, accuracy, sensitivity, and specificity of SNB were compared to histopathologic assessment of surgical specimens from NDs. Negative sentinel lymph nodes (SLNs) on histopathology were evaluated with step serial section (SSS) and immunohistochemistry (IHC). When a neck had a positive SLN, all lymph nodes of subsequent NDs were studied with SSS and IHC.

Results: There were primaries of the oral cavity (n=24), lip (n=3), oropharynx (n=3), and larynx (n=5). All patients had detected SLNs. In all, 41 necks were SLN-negative on histopathologic evaluation but 2 (5%) had metastases in non-SLNs after ND. Of these 41 necks, SLNs were level Ib (26%), IIa (45%), III (21%), and IV (8%). Nine necks presented positive SLN on histopathologic evaluation, level Ib (n=3), IIa (n=5), and III (n=2), and subsequent NDs were negative on conventional histopathologic analysis, but after SSS and IHC, two presented micrometastases.