The pathologic correlation between liver and portal vein invasion in perihilar cholangiocarcinoma: evaluating the oncologic rationale for the American Joint Committee on Cancer definitions of T2 and T3 tumors.

BACKGROUND: The American Joint Committee on Cancer (AJCC) has recommended that cancers with liver involvement be graded T2b and those with portal vein involvement be graded T3, although the value of staging as prognostic factors remains unclear. We evaluated the current definition of the T2/3 tumors for perihilar cholangiocarcinoma.
METHODS: A total of 202 patients with perihilar cholangiocarcinoma who underwent hepatectomy without vascular resection were enrolled. Clinicopathologic data about invasion of the liver and the unilateral portal vein were evaluated.
RESULTS: The liver and the unilateral portal vein were involved in 100 (49.5 %) and 38 (18.8 %) patients, respectively. The survival rates were not significantly different between patients with and without liver invasion (48.6 vs. 52.2 %, respectively, at 5 years, P = 0.157) and between patients with or without unilateral portal vein invasion (43.2 vs. 52.1 %, respectively, at 5 years, P = 0.363). The survival rate of patients with tumors staged pT2b was not significantly different from the rate of patients with pT2a (63.4 vs. 55.6 % at 5 years, P = 0.912), and the pT2b tumor patient survival rate was better than the rate of patients with pT3 (34.9 % at 5 years, P = 0.011). Using multivariate analysis, nodal metastasis (P = 0.003), positive surgical margin (P = 0.010), and Bismuth type IV tumor (P = 0.039) were identified as independent prognostic factors.
CONCLUSIONS: The liver and the unilateral portal vein are frequently involved in perihilar cholangiocarcinoma. The determinants of the current AJCC T2/3 tumor classifications are rational; however, subdivision of T2 tumors may be of less clinical value.