Clinical significance of tumor infiltration length along the bile duct mucosa and submucosa in hilar cholangiocarcinoma.

Background: Radical resection remains the mainstay of treatment for patients with hilar cholangiocarcinoma (HCCA), however, the scope of resection remains controversial. This study investigates the influence of tumor infiltration length along the mucosa and submucosa of the bile duct on curative resection.

Methods: The clinical and pathological data of 31 HCCA patients who underwent en bloc and extended liver resection in the Department of Biliary-Pancreatic Surgery of Sun Yat-sen Memorial Hospital from January 2020 to December 2021 were retrospectively analyzed. First, the gross tumor boundary and bile duct resection margin were marked with ink before the specimen was fixed in formalin solution. Subsequently, the specimens were embedded and sectioned longitudinally along the bile duct. Finally, the length of tumor invasion was calculated according to the marked macroscopic and microscopic boundaries. SPSS statistical software was used for statistical analysis.

Results: The average infiltration length in the proximal bile duct mucosa and submucosa were 8.5±5.2 and 8.6±4.9 mm, while the average infiltration length in the distal bile duct mucosa and submucosa were 12.8±7.5 and 11.5±7.2 mm, respectively. The accuracy of the Bismuth-Corlette classification for type III lesions was 68.4% (13/19).

Conclusions: Imaging examinations may underestimate the extent of HCCA growth along the bile duct. The R0 resection rate can be increased by extended hepatectomy including more than half of the liver volume.