Diagnostic evaluation of PET CT, USG neck & FNAC in clinically N0 neck

Abstract

Introduction : Extent of neck dissection is determined by the neck nodal positivity and indirectly has a bearing on neck dissection related morbidity. The current study prospectively compares the accuracy of these imaging techniques and FNAC to final histopathology. 31 patients of Oral cavity squamous cell carcinoma with no palpable lymphadenopathy were prospectively included in the study. Methodology : Thirty-one patients of oral cavity SCC who did not have any clinical lymphadenopathy treated at our centre from January 2018 to July 2018 were recruited for the study. All these patients underwent a whole body PET with contrast enhanced CT followed by a high-resolution ultrasound of the neck. Patients then underwent a US guided FNAC of the most suspicious lymph node. Results: 14 of the 31 patients had pathologically positive neck node. PET CT had 100 % negative predictive value. USG Neck diagnosed 22 patients to have suspicious lymph node with a negative predicitve value of 66.7% and positive predictive value of 50%. The combined yield of PET CT and USG Neck could produce a PPV of 100% and NPV of 68%. Conclusion : None of the test individually could predict the neck nodal positivity with absolute accuracy in our study. The best accuracy was when a combination of these tests were done.