Use of positron emission tomography/ computed tomography in the initial staging of head and neck squamous cell carcinoma: Accuracy in evaluation of the primary site of the tumor, metastases to cervical lymph nodes, and distant metastases.

Abstract

Our study aimed to evaluate the use of positron emission tomography/computed tomography (PET/CT) in the initial staging of head and neck squamous cell carcinoma (HNSCC), including assessment of local and distant spread of the disease. We also aimed to compare the accuracy of PET/CT in the evaluation of human papillomavirus (HPV) positive and HPV-negative oropharyngeal carcinoma. This single-center, prospective study was conducted between August 2016 and September 2021. A total of 198 patients with HNSCC who underwent PET/CT within the primary staging were included. We compared PET/CT results with histological findings. We calculated the accuracy, sensitivity, specificity, and positive and negative predictive values to assess the primary tumor, cervical lymph nodes, and distant metastases. PET/CT showed a high success rate (32%) in revealing the primary site of carcinoma of unknown primary (CUP). The accuracy of PET/CT in displaying the primary tumor, cervical lymph node metastases, and distant metastases was 89.4%, 85.4%, and 87.4%, respectively. The method provided high sensitivity but lower specificity in all three areas. Specifically, PET/CT showed low specificity in the assessment of small tumors (75%), metastatic involvement of cervical lymph nodes (69.6%), and HPV-positive oropharyngeal carcinoma (55.6%). The high accuracy of PET/CT to identify distant metastases and whole-body staging in one diagnostic step accelerated primary staging and resulted in earlier commencement of therapy. However, it also led to an overestimation of clinical findings and thus to extensive surgical treatment, especially in patients with small tumors, metastatic involvement of cervical lymph nodes, and HPV- positive oropharyngeal carcinoma. PET/CT is also useful for CUP diagnostics.