Abstract

Background: Liver resection is pivotal in treating incidental gallbladder cancer (IGBC). However, the adequate volume of liver resection remains controversial. Methods: A cross-sectional retrospective analysis was performed on resected IGBC patients between 1999 and 2018. Morbidity was evaluated according to the Clavien-Dindo classification. The theoretical volume of a 2-cm and 1.5-cm wedge liver resection was calculated (105 cm3 and 77.5 cm3, respectively) and used as reference. Overall survival (OS) was estimated using Kaplan-Meier and Cox regression analyses. Results: Among 111 patients re-resected for IGBC, 84 provided sufficient data to calculate liver resection volume. Patients with a resection volume ? 105 cm3 had a higher rate of overall morbidity (P = 0.001) and length of stay (P = 0.012), with no difference in mortality. There was no significant difference in OS according to residual cancer or T-category. A resection volume ? 77.5 cm3 was more frequent in T ? 3 than in T1–2 patients (P = 0.026), and residual cancer was higher (P = 0.041) among patients with ? 77.5 cm3 resected. Cox multivariate regression showed that residual cancer (HR = 11.47, P < 0.001), perineural/lymphovascular invasion (HR = 2.48, P = 0.021), and Clavien-Dindo ? IIIa morbidity (HR = 5.03, P = 0.003) predict worse OS, but not liver volume resection. Conclusion: There are no significant differences in OS based on resected liver volume of IGBC, when R0 is achieved. There is a significant difference in morbidity and length of stay when liver wedges are ? 105 cm3, which is lost when analyzed by Clavien-Dindo ? IIIa. A 77.5–105 cm3 resection is indicated in ? T3 patients, minimizing morbidity risk, while addressing concerns of overall survival. © 2023, Society of Surgical Oncology.