Comparison of clinicopathological characteristics and long-term survival between patients with gallbladder adenosquamous carcinoma and pure gallbladder adenocarcinoma after curative-intent surgery: a single-center experience in China and a meta-analysis

OBJECTIVE: The aim of the study was to evaluate the similarities and differences between gallbladder adenosquamous carcinoma (GBASC) and pure gallbladder adenocarcinoma (GBAC). METHODS: Patients with GBASC and GBAC from 2010 to 2020 were analyzed in terms of clinicopathological features and long-term survival. Moreover, a meta-analysis was also performed for further validation. RESULTS: Our experience: A total of 304 patients with resected GBC were identified, including 34 patients with GBASC and 270 patients with GBAC. Patients with GBASC had a significantly higher preoperative CA199 level (P <0.0001), a significantly higher incidence of liver invasion (P <0.0001), a relatively larger tumor size (P = 0.060), and a significantly higher proportion of patients with T3–4 (P <0.0001) or III–IV disease (P = 0.003). A comparable R0 rate was obtained between two groups (P = 0.328). A significantly worse overall survival (OS) (P = 0.0002) or disease-free survival (DFS) (P = 0.0002) was observed in the GBASC. After propensity score matching, comparable OS (P = 0.9093) and DFS (P = 0.1494) were obtained. Clear margin (P = 0.001), node metastasis (P <0.0001), T stage (P <0.0001), and postoperative adjuvant chemoradiotherapy (P <0.0001) were independent prognostic factors for OS for the entire cohort. Adjuvant chemoradiotherapy had a survival benefit for patients with GBAC, while the survival benefit was still being validated in patients with GBASC. Meta-analysis: With our cohort incorporated, a total of seven studies involving 1,434 patients with GBASC/squamous carcinoma (SC) were identified. GBASC/SC shared a worse prognosis (P <0.00001) and more aggressive tumor biological features than GBAC. CONCLUSION: GBASC/SC shared more aggressive tumor biological features and a much worse prognosis than those with pure GBAC.