Assessment of head and neck-imaging reporting and data system using fluro-deoxy-glucose-positron emission tomography/computerized tomography scan imaging of recurrence of head and neck tumors
Authors: Shanab Mohamed AbdelAziz Abo , Ahmed Abo Almagd Alnouby , Gad Azza Abdel-Hamid , Habba Mohamed Refaat , Al-Shatouri Mohammad Ahmad 
Published: May 2023

Abstract
Background
Worldwide, there are more than 550,000 new instances of head and neck cancer per year, with over 300,000 fatalities. Among the Middle Eastern nations, Egypt had one of the highest overall incidence rates of oral cavity and pharynx cancer (5.5/105). A consistent reporting form for head and neck cancer monitoring provides many crucial functions, including directing patient care with simply explained numerical scores for tumor recurrence suspicion levels. The Neck-Imaging Reporting and Data System (NI-RADS) assigns a numerical grade, from 0 to 4, where 0 represents incomplete, 1 represents no evidence of local recurrence (primary site) or adenopathy (neck), 2 represents low suspicion, 3 represents high suspicion, and 4 represents definite recurrence. Our aim was to improve the management outcome for patients liable to recurrence of head and neck cancers post-treatment with radio or chemotherapy using Neck-imaging Reporting and Data System (NI-RADS) after imaging with Fluro-Deoxy-Glucose-Positron Emission Tomography/Computed Tomography Scan (FDG-PET/CT Scan).

Materials and methods
The study setting was done at our institution and the type of study was combined prospective and retrospective study for 24 months from June 2020 to June 2022. The study population included 71 scans for 55 patients aged between 18 and 70 years, who had suffered from head and neck cancer and underwent treatment by chemotherapy or radiotherapy to follow up on their cases and determine recurrence or resolution of tumors.

Results
The results demonstrated the classification of tumor findings according to the degree of malignancy with 16.9% of scans were diagnosed as low pathological grade, 60.6% were diagnosed as intermediate pathological grade and 22.5% were diagnosed as high pathological grade. The initial tumor subsites in our study were as follow: the oral cavity with its different subsites represented the largest group constituting 11 cases (20%) of the total cases, and the larynx and vocal cords came next and constituted 10 cases (18.2%) of the total scans, nasopharynx constituted 9 cases (16.4%) of the cases. According to application of NI-RADS score, cases were classified as 17 cases NI-RADS (1), representing 30.1% of cases, 9 cases NI-RADS (2), representing 16.36% of cases, 18 cases NI-RADS (3), representing 32.7% of cases and 11 cases NI-RADS (4) representing 20% of cases. Percentage of recurrence in NI-RADS (1) was 1/17 representing 5.9%, in NI-RADS (2) was 2/9 representing 22.2%, in NI-RADS (3) was 12/18 representing 66.66%, in NI-RADS (4) was 10/11 representing 90.9% with total recurrence 25/55 cases representing 45.45%.

Conclusions
Neck-Imaging Reporting and Data System using FDG PET/CT Scan imaging for assessment of recurrence of head and neck tumors was a choice of relatively high sensitivity and specificity for improvement of significant results and guiding the clinician to the proper management strategy for the patients as well as organizing a strategy for follow-up of cases according to their score of NI-RADS.