Clinical evaluation of staging system for nasopharyngeal carcinoma: comparison of fourth and fifth editions of UICC TNM classification.

Staging nasopharyngeal carcinoma (NPC) by the UICC 4th-edition TNM classification system (the old system) did not give an accurate prognosis because of the uneven distribution of patients in each stage. This system was revised in 1997 (the new system). To evaluate the performance of the new system, 35 patients with NPC who had been staged by the old system were restaged according to the new system. Restaging of the patients resulted in an overall "downstaging." Differences in the overall survival rates of the early group (stages I, II, III), stage IVA, stage IVB, and stage IVC patients were statistically significant (75%, 48%, 74%, and 0%. respectively; p = .01). T4 was a significant factor of poor outcome (hazard rate, 2.932; 95% CI, 1.667 to 8.545), whereas N3 was not (hazard rate, 0.858; 95% CI, 0.281 to 2.618). The new staging system is more useful than the old system.