Validation Study for T Classification of Distal Bile Duct Carcinoma According to Depth of Invasion
Yuil Kim, Ahrim Moon, Kee-Taek Jang. Samsung Medical Center, Seoul, Korea
Background: In current AJCC staging system, T stage of distal bile duct carcinoma is classified according to tumor extent within or beyond the bile duct wall. However there are many cases those are difficult to clearly differentiate tumor extent within or beyond the bile wall because desmoplastic stromal reaction of invasive carcinoma obscures the boundary of bile duct wall. Alternative T stage by depth of invasion (DoI; T1: <5 mm, T2: 5 to 12 mm, and T3: >12 mm) has been proposed by Hong et al. In this study we validated new T stage by DoI in distal bile duct cancer.
Design: We evaluated the DoI in 101 cases of distal bile duct carcinoma with ruler tool of digital scan image. DoI was measured in two methods. First, DoI-1 was defined as distance between the basal lamina of the adjacent normal bile duct mucosa to the most deeply invasive tumor cells according to previously described by Hong el al. Second, DoI-2 was measured as distance from top of tumor to the most deeply invasive tumor cells except for intraductal papillary neoplasm.
Both data of DoI-1,2 were compared patient's survival. We also analyzed 101 cases of distal bile duct carcinoma by current T classification of 7th AJCC staging.
Results: T stage of current AJCC staging system showed poor correlation with patient's survival (p=0.157). However both new T classification by DoI-1,2 showed good correlation with patient survival with statistical significances (p=0.009 in DoI-1)(p=0.017 in DoI-2).
Conclusions: On the basis of the present data, we think that new T classification by DoI using cut-off value of 0.5 and 1.2 cm, which is measured from the basal lamina of the adjacent normal bile duct or top of tumor to the most deeply invasive tumor cells, is more appropriate T classification for distal bile duct carcinoma that showed good correlation with patient's survival. DoI could be more practical and reliable method in T classification of distal bile duct cancer staging.
Wednesday, March 6, 2013 1:00 PM
Poster Session VI # 125, Wednesday Afternoon