Comparison of clinicopathological characteristics and survival outcomes between gallbladder mucinous adenocarcinoma and gallbladder adenocarcinoma: A propensity score-matched study.

Background: Gallbladder mucinous adenocarcinoma (GBMAC) is a rare subtype of gallbladder adenocarcinoma (GBAC), with limited knowledge of its survival outcomes from small case series and single-center retrospective analysis.

Aim: To compare the clinicopathological characteristics of GBMAC with typical GBAC and its prognostic factors to gain insights into this field.

Methods: This study was conducted using data from the Surveillance, Epidemiology, and End Results database, including cases of GBMAC and typical GBAC diagnosed from 2010 to 2017. The Pearson chi-square test or Fisher exact test was used to examine the differences in clinicopathological features between these two cohorts. In addition, propensity score matching (PSM) analysis was performed to balance the selection biases. Univariate and multivariate Cox hazards regression analyses were performed to determine independent prognostic factors for cancer-specific survival (CSS) and overall survival (OS). The Kaplan-Meier curves and log-rank tests were used to assess the OS and CSS of GBMAC and typical GBAC patients.

Results: The clinicopathological and demographic characteristics of GBMAC were different from typical GBAC. They included a larger proportion of patients with unmarried status, advanced American Joint Committee on Cancer (AJCC) stage, higher T stage, higher N1 stage rate and lower N0 and N2 stage rates ( < 0.05). Multivariate analyses demonstrated that surgery [OS: Hazard ratio (HR) = 2.27, = 0.0037; CSS: HR = 2.05, = 0.0151], chemotherapy (OS: HR = 6.41, < 0.001; CSS: HR = 5.24, < 0.001) and advanced AJCC stage (OS: Stage IV: HR = 28.99, = 0.0046; CSS: Stage III: HR = 12.31, = 0.015; stage IV: HR = 32.69, = 0.0015) were independent prognostic indicators for OS and CSS of GBMAC patients. Furthermore, after PSM analysis, there was no significant difference between GBMAC and matched typical GBAC patients regarding OS ( = 0.82) and CSS ( = 0.69).

Conclusion: The biological behaviors of GBMAC are aggressive and significantly different from that of typical GBAC. However, they show similar survival prognoses. Surgery, chemotherapy, and lower AJCC stage were associated with better survival outcomes. Further research is needed in the future to verify these results.