Background & objective: Along with the development of treatments, different tumor staging systems are coexisted and have been modified. This study was to validate the rationality of the Fuzhou staging system (1992) of nasopharyngeal carcinoma (NPC), and to provide some suggestions.
Methods: A total of 915 NPC patients received radical radiotherapy alone in Cancer Center of Sun Yat-sen University from Jan. 1997 to Dec. 1998. The 1-, 3-, and 5-year follow-up rates were 98.7%, 95.2%, and 91.7%, respectively. The survival data were analyzed with Life table, Cox regression, Kaplan-Meier, and log-rank methods.
Results: The 1-, 3-, and 5-year overall survival rates of the 915 patients were 87.69%, 72.73%, and 64.44%; the 1-, 3-, and 5-year disease-freely survival rates were 86.87%, 69.72%, and 58.33%, respectively. Cox regression analysis showed that the 5-year survival statuses of the 915 patients were significantly correlated with their age and the tumor stage classified by the Fuzhou staging system (1992); the 5-year survival statuses of the 803 patients no more than 60 years old were only significantly correlated with tumor stage, and had no correlation with their age. Life table analysis validated that the tumor stage classified by Fuzhou staging system (1992) can roughly predict the prognosis, but the difference between the 5-year survival rates of stage I and II patients was not significant. Kaplan-Meier analysis showed no significant difference between survival statuses of stage T1 and T2 patients when adjusted by N classification. Therefore, we adjusted stage T2 without parapharyngeal space invasion to stage T1, stage T3 with carotid vagina invasion to stage T2, stage T4 with paranasal sinus involvement to stage T3, stage T3 with cranial nerve injury to stage T4, and stage N1 with bilateral lymph nodes involvement to stage N2. After the modifications, the differences among stage I to IVa, stage T1 to T4 (adjusted by N stage), or stage N0 to N3 (adjusted by T stage) were significant.
Conclusion: Taking the impact of age on the prognosis and the interaction between T stage and N stage into consideration, the above modifications of should be included when renewing the Fuzhou staging system (1992).