Diagnosis of Post-Radiotherapy Local Failures in Nasopharyngeal Carcinoma: A Prospective Institutional Study

BACKGROUND This prospective study was conducted to evaluate and compare the efficacies of nasopharyngoscopy and CT scan in the diagnosis of local failure of external beam radiotherapy (EBRT) for nasopharyngeal carcinoma. METHODS Total 52 patients of histopathologically proven nasopharyngeal carcinoma treated with external beam radiotherapy (EBRT), were included in this study. For every patient computed tomography (CT), nasopharyngoscopy and nasopharyngeal biopsies were performed 3 months after completion of EBRT. RESULTS Three months after completion of EBRT, 9 patients (17.3%) had evident disease on histological examination of biopsies. Nasopharyngoscopy showed 77.78% sensitivity, 93.03% specificity, 70% positive predictive value and 95.24% negative predictive value in diagnosing the residual/recurrence of tumor. There was statistically significant agreement between the endoscopic findings and the histological findings (Kappa reliability coefficient=0.562, p<0.01). On the other hand, CT scan showed a 55.56% sensitivity, 39.53% specificity, 16.13% positive predictive value and 80.95% negative predictive value in diagnosing the residual tumor/recurrence. There was no statistically significant agreement between the CT scan findings and the histological findings (Kappa reliability coefficient = 0.038, p>0.05). CONCLUSION Nasopharyngoscopy should be considered the primary follow-up tool after radiotherapy of nasopharyngeal carcinoma. CT scan should be reserved for patients with histological or any symptomatic indications. Routine postnasal biopsies are not required.