Comparison of AJCC 1988 and 1997 classifications for nasopharyngeal carcinoma

Purpose: A comparison of American Joint Committee on Cancer (AJCC) 1988 and 1997 nasopharyngeal carcinoma (NPC) classifications was made in terms of patient distribution and efficacy in predicting prognosis. Methods and Materials: Between 1993-1997, 90 patients (64 M, 26 F) with non-metastatic NPC were treated. The mean age was 42.02 (range: 9-82) years old. Histopathological diagnosis was WHO 2 and 3 in 83 (92.2%) patients. All patients were prospectively staged using AJCC 1988 and modified Ho's classifications (1989) and these data were stored in a computer database. Retrieval of this information enabled us to restage patients according to the AJCC 1997. Median follow-up was 38 months. Results: According to the AJCC 1988 there were 2 (2.2%), 6 (6.7%), 13 (14.4%), and 69 (76.7%) patients in Stage I, II, III and IV, respectively. Same figures were 8 (8.8%), 21 (23.3%), 26 (28.9%), and 35 (38.8%), according to AJCC 1997. Three year overall survival (OS) rates were 100%, 100%, 67%, and 62% for patients Stage I, II, III, and IV according to the AJCC 1988 and 100%, 72%, 65%, and 55%, (I vs. IV; p = 0.03, I vs. III; p = 0.05) respectively, according to the AJCC 1997. Three year loco-regional relapse free survival (LRRFS) rates were 50%, 100%, 100%, and 83% (I vs. III; p = 0.03) for patients in Stage I, II, III, and IV according to the AJCC 1988. Same figures were 88%, 90%, 89%, and 85% according to the AJCC 1997. Three year distant metastasis free survival (DMFS) rates were 100%, 100%, 82%, and 67% for patients in Stage I, II, III, and IV according to the AJCC 1988. Same figures were 100%, 74%, 80%, and 57% (I vs. IV; p= 0.03) according to the AJCC 1997. We did not observe any significant difference in LRRFS among T stages for both staging system and the N stage was the primary determinant for DMFS in both systems. Conclusions: We observed a better patient distribution with AJCC 1997 comparing to AJCC 1988. The new classification also attained better statistical significances among stages in the OS and DMFS rates