T2a gallbladder cancers have better overall survival and lower recurrence than T2b: a systematic review and meta-analysis

Abstract

Presenter: Wasfi Alrawashdeh MD, PhD | Newcastle Freeman Hospital Background: Radical cholecystectomy including some form of liver resection and lymphadenectomy is the most widely accepted surgical treatment for T2 gallbladder cancer. However, the re classification of T2 into T2a (peritoneal side) and T2b (hepatic side) in the 8th edition of the AJCC TNM staging triggered further debate regarding the optimal treatment of these tumours. Some advocate liver resection only for T2b tumours based on survival data but studies have reported conflicting results in terms of survival and recurrence in T2a and b tumours. We aimed to perform a systematic review and meta-analysis to investigate the long-term survival and recurrence for T2a and T2b gallbladder cancers. Methods: Literature search of Medline, Web of science, Embase and Cochrane databases up to Sept 2020 was performed. Search criteria included T2 gallbladder cancer as well as T2a, T2b, peritoneal side and hepatic side tumours. Data was extracted including study characteristics, survival and recurrence. Where available, patient data were extracted from published Kaplan Meier curves for individual patient meta-analysis. The Meta-analysis was performed using random effect model. Results: The systematic review identified 15 retrospective studies that met the inclusion criteria including 2531 patients. There was no randomised controlled trail. In standard meta-analysis. overall survival was significantly worse in T2b compared to T2a tumours (HR 2.18, 95% CI 1.67-2.86, p <0.0001). Individual patient data meta-analysis showed similar results (629 patients, HR 1.92, 95%CI 1,43-2.58, p<.00001). T2b tumours had higher risk of disease recurrence compared to T2a (OR 3.19, 95% CI 1.40-7.28, p= 0.006) and were more likely to receive adjuvant chemotherapy (OR 1.76, 95% CI 1.12-2.84, p 0.014). All studies had moderate to high risk of bias. Conclusion: T2a gallbladder tumours have better overall survival and reduced risk of recurrence when compared to T2b tumours. The data is however derived from retrospective studies and there is no consistent evidence to support specific surgical strategy for each stage. Further better controlled and larger scale studies are required to generate better quality data.