A comparison of Ho's, International Union Against Cancer, and American Joint Committee stage classifications for nasopharyngeal carcinoma. Five hundred sixty-four nasopharyngeal carcinomas (NPC), mostly of undifferentiated histologic type, were studied for survival, distant metastasis, and local recurrence. All had computerized tomography of the nasopharynx and skull base (CT-NP) and fiberoptic nasopharyngoscopy for evaluation of the primary tumor. Regional disease was assessed by palpation. A computer data base was formed on presentation, containing all information required for staging according to Ho's, the International Union Against Cancer (UICC), and the American Joint Committee (AJC) classifications. The three were compared for their efficacy in predicting prognosis. Ho's classification was superior to the other two because its overall stages differed from one another more significantly in the actuarial survival (ASR), disease-free survival (DFS), and freedom from distant metastasis (FDM) rates, and its N staging was more accurate in predicting FDM. Stages T1 and T2 of UICC/AJC were similar in the freedom from local recurrence rate (FLR) and should be grouped together, equivalent to Ho's T1. A more even patients number distribution among the stages also favored the use of Ho's classification. 