Prognostic significance of the tumor-stroma ratio in gallbladder cancer

Abstract

In recent years, the tumor-stroma ratio (TSR) has attracted increasing attention as an independent prognostic factor for several solid tumors. However, the importance of the stromal compartment has not been investigated yet in gallbladder cancer (GBC). The objective of this study is to investigate the prognostic value of TSR in GBC and the relationship between TSR and other known prognostic parameters. A total of 51 patients who underwent operations for gallbladder carcinoma were selected for this study. TSR was determined on haematoxylin and eosin (H&E)-stained sections by two independent investigators. Stromal ratio groups were classified as stroma-poor (ratio of stroma < 50%) and stroma-rich (ratio of stroma >50%). The Mann-Whitney test, the Chi-squared test, the Kaplan-Meier method, and the Cox proportional hazards model were used to analyze the data. The median survival time for patients in the stroma-rich group was 6.00 months (95% CI, 4.47–7.54). In contrast, for the stroma-poor group, the median survival time was 17.00 months (95% CI, 3.64-30.36). The 3-year overall survival rate was 19.7% in the stroma-poor group and 7.2% in the stroma-rich group. Patients with stroma-rich tumors had a worse prognosis than those with stroma-poor tumors (log-rank P = 0.004). According to the univariate analysis, the TSR, differentiation grade, pTNM stage, and operative methods were shown to be related to overall survival (OS) with statistical significance. The hazard ratio (HR) of TSR was 2.428 (95% CI, 1.29-4.58; P = 0.006). However, the TSR did not prove to be an independent prognostic factor in the multivariate analysis. Our study demonstrated that the tumor-stroma ratio (TSR) is an important prognostic parameter for gallbladder cancer (GBC). Stroma-rich tumors were associated with poor overall survival.