Nasopharyngeal carcinoma: Early detection and prognostic factors

Abstract

Population screening programmes which combine serology (antibodies against the Epstein Barr virus) and indirect mirror examination of the nasopharynx have successfully effected early detection of nasopharyngeal carcinoma (NPC) in studies in southern China. The cost of such a screening programme, and the lower prevalence of this disease in other parts of the world, however, may limit its wider application. Various features of NPC, including histopathology, titre of various antibodies against the EBV, sex and age at diagnosis have been reported as of prognostic importance but their value remains controversial, and stage remains the most important prognostic factor. Unfortunately, there has been no universally accepted stage classification for NPC. Most of the more widely accepted stage classifications do not take into consideration paranasopharyngeal extension of the tumour despite the computed tomography finding that such extension is an early event in the course of the disease. A quantitative method of evaluating paranasopharyngeal extension of the tumour has been proposed and found to have correlation with local control of the tumour. More controversy exists for the N staging over the relative importance of the size and the level of nodal involvement. Both of these have been documented as important prognostic parameters. They, perhaps, have changing importance at different times after treatment of the disease: size of node is more related to local control of the nodal disease and hence short term prognosis, while the level of nodal involvement is more related to distant metastases and, hence, long- term prognosis.