Purpose

This study evaluated discriminatory value of newly proposed AJCC 8th staging system compared to the AJCC 7th staging system for gallbladder cancer. 

Methods

We retrospectively reviewed database of 522 patients who underwent curtive intent surgery for gallbladder cancer at a single institute from January 2006 through June 2016. Clinicopathologic characteristics and survival rates were analyzed based on 7th and 8th edition of AJCC staging system, respectively.

Results

There was significant different in survival rates between T2a and T2b(P<0.001). Among pathologically-stage patients, P values for pairwise comparisons among different 8th AJCC stage were significant(P<0.05) for stage IIa vs IIb and IIIa vs IIIb. Notably, the new edition improved the power of discrimination slightly in overall survival and disease-free survival (c-indices: 0.711, 0.723) compared with the 7th edition (c-indices:0.698, 0.714). There were no significant difference between N1 vs N2 in both stage group(P=0.578, 0.283).

Conclusions

Compared to the 7th system, the 8th system bring significant prognostic improvement for stage IIa vs IIb. However, lymph node staging does not reflect well the prognosis in both classification by number or location based staging system.