Background: This study was designed to address whether gallbladder cancer invading the muscle layer (stage pT(1b)) is a local disease and whether radical resection is necessary.
Methods: A retrospective analysis of 25 patients with pT(1b) gallbladder tumours, 13 of whom underwent simple cholecystectomy and 12 radical resection with regional lymph node dissection, was performed. A total of 147 regional lymph nodes was examined for metastasis. The median follow-up time was 95 months.
Results: No patient had blood vessel or perineural invasion on histology. Lymphatic vessel invasion was seen in one patient. Both overt metastasis and micrometastases were absent in all lymph nodes examined. Overall 10-year survival was 87 per cent. The outcome after simple cholecystectomy was comparable to that after radical resection (P = 0.16). Two patients who underwent radical resection died from tumour relapse in distant sites.
Conclusion: Most pT(1b) gallbladder carcinomas spread only locally. Additional radical resection is not necessary when the depth of invasion of gallbladder carcinoma is limited to the muscle layer after simple cholecystectomy.