Intramucosal Extent as a Marker for Advanced Disease and Survival in Gallbladder Adenocarcinoma

Background: Gallbladder cancer (GBC) is the most common biliary tract malignancy and has a poor prognosis. The clinical significance of focal vs diffuse GBC remains unclear. Methods: A retrospective review was conducted on all patients with non-metastatic GBC at a quaternary care center. Pathology was reviewed, and gallbladder cancer pattern was defined based on the extent of mucosal involvement; "diffuse" if the tumor was multicentric or "focal" if the tumor was only in a single location. Patients undergoing liver resection and portal lymphadenectomy were considered to have definitive surgery. The primary outcome was overall survival and assessed by Kaplan-Meier curves. Results: 63 patients met study criteria with 32 (50.7%) having diffuse cancer. No difference was observed in utilization of definitive surgery between the groups (14 [43.8%] with focal and 12 [38.7%] with diffuse, P = .88). Lymphovascular invasion (P = .04) and higher nodal stage (P = .04) were more common with diffuse GBC. Median overall survival was significantly improved in those with focal cancer (5.1 vs 1.2 years, P = .02). Although not statistically significant, this difference in overall survival persisted in patients who underwent definitive surgery (4.3 vs 2.4 years, P = .70). Discussion: Patients with diffuse involvement of the gallbladder mucosa likely represent a subset with aggressive biology and worse overall survival compared to focal disease. These findings may aid surgeons in subsequent surgical and medical decision-making for patients with GBC.