Is a specific T classification needed for extrahepatic intraductal papillary neoplasm of the bile duct (IPNB) type 2 associated with invasive carcinoma?

Background: The necessity of a specific T classification for extrahepatic intraductal papillary neoplasm of the bile duct (IPNB) type 2, one of the precursors of cholangiocarcinoma (CC), remains unclear. Methods: Patients who underwent resection for extrahepatic biliary tumors were reviewed. Relapse‐free survival (RFS) was compared between IPNB type 2 and CC, stratified by T classification. Results: The cohort involved 443 patients with IPNB type 2 (n = 57) and CC (n = 386). In 342 patients with perihilar tumors, 5‐year RFS of IPNB type 2 and CC group was 49.8% versus 34.5% (p =.012), respectively. The RFS was 54.6% versus 47.2% (p =.110) for pT1‐2 tumors and 28.6% versus 22.7% (p =.436) for pT3‐4 tumors, respectively. In 92 patients with distal tumors, 5‐year RFS was 47.4% versus 42.1% (p =.678). The RFS was 68.2% versus 49.6% (p =.422) for pT1 tumors and 18.8% versus 38.3% (p =.626) for pT2‐3 tumors, respectively. Multivariate analysis identified that poor histologic grade (HR, 2.105; p <.001), microscopic venous invasion (HR, 1.568; p =.002), and nodal metastasis (HR, 1.547; p <.001) were independent prognostic deteriorators, while tumor type (IPNB type 2 vs. CC) was not. Conclusions: Prognostic impact of IPNB type 2 was limited, suggesting unnecessity of a specific T classification for IPNB type 2 with invasive carcinoma. [ABSTRACT FROM AUTHOR]