Comparison of Prognostic Performance of 8th and 7th Edition of AJCC Staging System for Patients With Gallbladder Cancer Undergoing Curative Intent Surgery

Background: We compared the predictive performance of the 7th and 8th editions of the AJCC staging systems in stratifying disease-related survival outcomes in patients with GBC undergoing curative intent surgery.

Methods: Patients that underwent curative intent surgery for GBC at our institution (2014 and 2021) were included in the study. Various clinico-pathological data were extracted to perform Kaplan-Meier survival analysis.

Results: A total of 240 patients were included in the study. Both, TNM-7, and TNM-8 staging systems can stratify patients into stages with statistically significant differences in disease-free and overall survival. Survival rates drop with stage progression. Using TNM-8, 8/240 (3.33%) patients were upstaged from Stage IIIB (TNM-7) to IVB (TNM-8) and 12/240 (5%) were down-staged from Stage IVB(TNM-7) to IIIB(TNM-8). Survival curves of the re-classified patients matched those of the corresponding TNM-8 stage. Additionally, there was statistically significant difference in their survival (p < 0.001) compared to their corresponding TNM-7 stage. There was no statistically significant difference in survival rates between stages IIA, IIB (TNM-8), and stage II (TNM-7). However, stage IIA had a slightly better survival than stage IIB.

Conclusion: Though both TNM-7 and TNM-8 are useful for stratifying patients with GBC, TNM-8 has a better prognostic performance than TNM-7.