Accuracy of Computed Tomography Pretreatment Staging and Post-treatment Recurrence in Head and Neck Cancers in Rural Western India- A Retrospective Observational Study

Abstract

Introduction: Cancers of head and neck are the most common in developing countries especially, in India. Multi-disciplinary approach and treatment are required in management of head and neck cancers which include surgeries, radiotherapy techniques and chemotherapy regimens. These can complicate the post-treatment imaging field and contribute to difficulties in image interpretation. Knowledge of these expected post- treatment changes, possible complications and the capability to identify early changes of tumour recurrence is an integral part of post-treatment surveillance and effective management. Aim: To evaluate the effectiveness of Multi-Detector Computed Tomography (MDCT) in pre-treatment staging, post-treatment response and recurrence in comparison with Positron Emission- Computed Tomography (PET-CT). Materials and Methods: A retrospective observational study was conducted including 101 patients, undergoing pre- and post-treatment, contrast enhanced CT scan with sections from skull base to base of neck. The pre-treatment imaging of primary tumour was assessed for its Tumour (T) and Node (N) stage with corresponding staging on histopathology. The imaging observations on pre- and post-treatment scans, for outcomes on recurrence, residual disease and cure were considered. Recurrence when suspected on post-treatment CT scan was confirmed with PET-CT or biopsy. The agreement of T and N staging on pre-treatment CT scan with that on histopathology was examined using quadratic weighted kappa. Sensitivity and specificity for detection of post-treatment recurrence on CT scan was determined by measuring true positive rates and true negative rates. Results: An agreement of 0.4 and 0.58 (kappa coefficient) was found between T and N staging on CT and histopathology which suggests fair accuracy of CT in pretreatment staging of head and neck cancers. The CT had a sensitivity and specificity of 88.89% and 100% for detecting recurrence in head and neck cancers in post-treatment neck CT scan in the background of post-treatment imaging changes. Conclusions: MDCT is a good imaging tool in pre-treatment staging of head and neck cancers. It effectively detects recurrence in the background of post-treatment changes. A standard post-treatment evaluation protocol should be followed.