SCC Antigen Concentrations in Fine-Needle Aspiration Samples to Detect Cervical Lymph Node Metastases: A Prospective Analysis.

Objective: To determine the diagnostic value of measuring squamous cell carcinoma antigen (SCC-Ag) and cancer antigen 15-3 (CA15-3) concentrations in fine-needle aspiration (FNA) samples for the detection of squamous cell carcinoma (SCC) metastases in cervical lymph nodes.

Study Design: A prospective study with patients consecutively included between November 2018 and May 2021.

Setting: A tertiary head and neck oncologic center.

Methods: Out of 138 patients, SCC-Ag concentrations were analyzed in 168 FNA cervical lymph node samples and CA15-3 in 152 samples. Results were compared with FNA cytology (FNAC) or definitive histology to establish sensitivity and specificity rates.

Results: For the detection of cervical SCC lymph node metastases, SCC-Ag measurement had an 89.4% sensitivity and 79.3% specificity at a cutoff concentration of 0.1 µg/L. Measurement of CA15-3 concentration in addition to SCC-Ag concentration did not lead to improved accuracy for the detection of SCC. In histology-confirmed cases, FNAC had an 80.0% sensitivity and 100% specificity, as opposed to 93.3% and 57.1%, respectively, for SCC-Ag.

Conclusion: Measurement of SCC-Ag concentration for detection of SCC lymph node metastases has a sensitivity at least comparable to FNAC and could be used as a relatively cheap screening tool in samples with nondiagnostic or indeterminate FNAC results or when multiple lymph nodes are sampled. However, SCC-Ag in FNA samples has a lower specificity than FNAC assessed by pathologists experienced in head and neck oncology. Addition of CA15-3 measurement did not lead to improved accuracy.