Background : Although most guidelines recommend extended cholecystectomy for T1b GB cancer, because of a lack of evidence, its optimum management remains controversial. The aim of this study was to investigate the clinical outcomes of T1b gallbladder cancer (GBC), and to determine an appropriate surgical strategy using Korea Tumor Registry System Biliary Pancreas (KOTUS-BP) Database.

Methods : Between 2000 and 2020 the Korea Tumor Registry System Biliary Pancreas (KOTUS-BP) database was used to identify and enroll a total 326 patients with pathologically diagnosed T1b GBC who underwent curative resection. Clinicopathological findings and long-term follow-up results including survival and recurrence were analyzed.

Results : Mean age of the 326 patients was 65-years and the male to female ratio was 1:1.1. Simple cholecystectomy with or without lymph node dissection was performed in206 patients (61.3 %) and extended cholecystectomy was performed in 126 patients (38.7%). Lymph node metastasis was observed in 13 (4.0% ) patients. No significant 5- year survival rate difference was observed between those that underwent simple cholecystectomy or extended cholecystectomy (82.7 vs. 82.9%, p=0.91), regardless of whether lymph node dissection was performed or not (82.9 vs.47.7%, p<0.001). However, a significant 5- year survival rate difference was observed between the patients with or without lymph node metastasis (84.1 vs. 0%, p=0.87). Recurrence occurred in 31 patients (9.5%) at median 16.9 months after surgery.

Conclusions : There was no superiority of extended cholecystectomy over simple cholecystectomy in the aspect of survival and recurrence in T1bGBC. Furthermore, the effectiveness of regional lymphadenectomy for treatment purpose remains questionable. However, because presence of lymph node metastasis showed poor prognosis in T1b GBC, lymph node dissection should be performed for the purpose of accurate staging and further adjuvant treatment.