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

Abstract

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. 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. 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. Prognostic impact of IPNB type 2 was limited, suggesting unnecessity of a specific T classification for IPNB type 2 with invasive carcinoma.