Evaluation of the New American Joint Committee on Cancer Staging Manual 8th Edition for Perihilar Cholangiocarcinoma

Background The aim was to compare the prognostic accuracy of cross-sectional imaging of the 7th and 8th editions of the American Joint Committee on Cancer(AJCC) staging system for perihilar cholangiocarcinoma(PHC). Methods All patients with PHC between 2002 and 2014 were included. Imaging at the time of presentation was reassessed and clinical tumor-node-metastasis (cTNM) stage was determined according to the 7th and 8th editions of the AJCC staging system. Comparison of the prognostic accuracy was performed using the concordance index (c-index). Results A total of 248 PHC patients were included;45 patients(18.1%) underwent a curative-intent resection, whereas 203 patients(81.9%) did not because they were unfit for surgery or were diagnosed with locally advanced or metastatic disease during workup. Prognostic accuracy was comparable between the 7th and 8th editions (c-index 0.57 vs 0.58). For patients who underwent a curative-intent resection, the prognostic accuracy of the 8th edition (0.67) was higher than the 7th (0.65). For patients who did not undergo a curative-intent resection, the prognostic accuracy was poor in both the 7th as the 8th editions (0.54 vs 0.57). Conclusion The 7th and 8th editions of the AJCC staging system for PHC have comparable prognostic accuracy. Prognostic accuracy was particularly poor in unresectable patients.