Evaluation of recurrent nodal disease after definitive radiation therapy for nasopharyngeal carcinoma: diagnostic value of fine-needle aspiration cytology and CT scan

BACKGROUND: Recurrent nodal disease in patients with nasopharyngeal carcinoma (NPC) after definitive radiotherapy presents a difficult clinical problem. This cohort of patients poses a diagnostic challenge to the head and neck surgeon because evaluation of the post-irradiated neck, both clinically and radiologically, is known to be difficult, and it is not uncommon for neck dissection specimen in suspected recurrent nodal disease to contain no viable tumor cells. Currently, there is no well-accepted method for the preoperative determination of the presence of malignancy in these nodal diseases. METHODS: Over a 7-year period in a tertiary hospital, we systematically reviewed the clinical charts of 42 patients with NPC who were diagnosed with suspected recurrent nodal disease, after radical definitive radiotherapy. Fine-needle aspiration cytology (FNAC) was performed on clinically palpable nodes and results were correlated with final histopathologic results. Findings on CT scan were also correlated with final histopathologic specimens. RESULTS: The specificity and sensitivity of FNAC was 75.0% and 75.0%, respectively. The positive and negative predictive value of FNAC was 93.8% and 37.5%, respectively. CT scan had a positive predictive value of 78.6%. The negative predictive value for multilevel involvement on CT scan was 20%. CONCLUSION: Radiological imaging and FNAC are useful diagnostic modalities in assessing recurrent nodal disease in the post-irradiated neck in patients with NPC. Although routine CT scan criteria for pathologic lymphadenopathy cannot be accurately applied in the post-irradiated neck, it is a useful surveillance tool in the routine follow-up of patients with post-irradiated neck with NPC. Clinicians, however, must understand their limitations when assessing these patients. The possibility of negative neck dissection must be conveyed to the patients.