Summary: T2 (tumor invades perimuscular connective tissue; no extension beyond serosa or into liver) gallbladder cancer has generally been treated by S4aS5 subsegmentectomy (S4aS5 HR). We investigated the therapeutic effect of full-thickness cholecystectomy (FC) and gallbladder bed resection (GBR), in terms of tumor location and resection margin (distance from the tumor). At our department we employ the following protocol to determine the extent of resection needed to achieve R0 status: (1) A tumor located in the gallbladder fundus (Gf) or body (Gb) and only on the free peritoneal side was classified as P-type, for which full-thickness cholecystectomy and regional lymph node dissection were performed. (2) A tumor located in Gf or Gb and in contact with the liver bed was classified as H-type, for which gallbladder bed resection and regional lymph node dissection were performed. (3) A tumor located in the gallbladder neck (Gn) was classified as N-type, for which gallbladder bed resection, bile duct resection, and regional lymph node dissection were performed.

Twenty-two patients admitted to our department between January 2000 and December 2014 with pT2gallbladder cancers were included in our study. Surgical procedures performed were compared with those specified in our protocol, and patients in whom the extent of resection was greater than that specified in our strategy were evaluated clinicopathologically and in terms of recurrence and the prognosis.

Six (27.2%), 7 (31.8%), and 9 (40.9%) patients underwent limited, standard, and extended surgery, respectively. Ten (66.7%) of 15 patients with tumors close to the liver bed underwent cholecystectomy or extended surgery, 7 (85.7%) of 8 patients with tumors close to the bile duct underwent bile duct resection, and 16 (72.7%) of 22 patients underwent regional lymph node dissection.

Recurrence at the bile duct resection margin, para-aortic lymph node metastasis, and hepatic metastasis occurred in 2, 1, and 3 patients, respectively. The 3-year survival rates (for patients including those dying of noncancer causes) were 50, 100, and 75% after limited, standard, and extended surgery, respectively.

There was a significant difference in the survival rate of patients who underwent standard or extended surgery (P=0.0273).

Favorable results were obtained in T2 gallbladder cancer patients without performing S4aS5 subsegmentectomy. Depending on the tumor location, neither full-thickness cholecystectomy nor gallbladder bed resection appeared to pose problems regarding recurrence or prognosis.

In conclusion, surgical treatment based on our protocol, which aims to achieve the condition of R0, may result in a sufficient therapeutic effect.