Published online May 14, 2022. doi: 10.3748/wjg.v28.i18.1996
Peer-review started: November 13, 2021
First decision: January 9, 2022
Revised: January 22, 2022
Accepted: March 26, 2022
Article in press: March 26, 2022
Published online: May 14, 2022
Incidental gallbladder cancer (IGBC) represents 50%-60% of gallbladder cancer cases. Data are conflicting on the role of IGBC diagnosis in oncological outcomes. Some studies suggest that IGBC diagnosis does not affect outcomes, while others that overall survival (OS) is longer in these cases compared to non-incidental diagnosis (NIGBC). Furthermore, some studies reported early tumour stages and histopathologic characteristics as possible confounders, while others not.
GB cancer is an uncommon malignancy with poor survival. Data suggest whether the diagnosis is incidental or not may play a role in the oncological outcomes. Confirmation of this observation may lead in further research aiming to better identify the reasons and refining the treatment strategy based on the presenting diagnosis.
This study aimed to investigate the role of IGBC diagnosis on patients’ overall survival, especially after surgical treatment with curative intent.
This is a retrospective analysis of all patient referrals with gallbladder cancer between 2008 and 2020 in a tertiary hepatobiliary centre. All patients had complete staging and were discussed in the multidisciplinary meeting prior to deciding on the treatment plan. Demographic, surgical and tumour variables were collected and compared between patients with IGBC and NIGBC using the appropriate statistical tests. Survival curves for OS and DFS were created using Kaplan-Meier method and compared with the log rank test. Risk analysis for independent predictors of OS and DFS was performed with univariable time to event analysis using the Cox proportional hazard model. Factors with a P value of < 0.200 were entered into a multivariable model and independent predictors (those with P < 0.05) were indentified. All statistical analysis was done using the software SPSS for Windows (Version 25.0, SPSS Inc., Chicago, IL, United States).
261 patients with GB cancer were included. Almost one-third pf patients had IGBC (91/261 patients) and two-thirds had NIGC. A total of 90/261 (34%) patients proceeded to have oncological resection. Metastatic disease was the most common reason for not having oncological resection. Patients with NIGBC were more likely to have advanced T stages of the disease and required more extensive resections than patients with IGBC. Survival analysis shows that patients with IGBC had better OS than patients with NIGBC in the whole cohort (29 vs 4 mo, P < 0.001), as well as in the non-surgical (14 vs 2 mo, P < 0.001) and surgical subgroups (29 vs 16.5 mo, P = 0.001). DFS was similarly better in patients with IGBC who underwent oncological resection (21.5 mo vs 8.5 mo, P = 0.007). After univariable and multivariable risk analysis, N stage, resection margin status and non-incidental diagnosis were identified as independent predictors of OS. N stage and resection margin status were also independent predictors of DFS. Within the limitations of a retrospective single centre study, our data suggest that difference in the oncological outcomes between the two groups cannot be solely explained by differences in pathologic or tumour features.
Our study suggests that IGBC diagnosis may confer a survival advantage, including patients that received surgical treatment, independently of the pathological stage and tumour characteristics. Prospective studies are required to investigate the reasons behind this, including detailed pathological analysis and molecular gene expression.
Published evidence is still contradicting. The theory that IGBC and NIGBC are two distinct variants of the same disease remains to be proven by detailed pathologic assessment and research in cancer molecular genetics.