Tumor Budding as a Predictive Marker of Relapse and Survival in Patients With Stage II Colon Cancer

BACKGROUND/AIMTumor budding (TB) has recently been recognized worldwide as a prognostic predictor in several solid cancers. The objective of this study was to explore the relationship between TB and clinicopathological characteristics, postoperative relapse, and survival in patients with stage II colon cancer. PATIENTS AND METHODSA total of 213 patients with stage II colon cancer were retrospectively enrolled at Saitama Medical Center, Dokkyo Medical University from 2010 to 2016. TB was evaluated in hotspot areas on hematoxylin and eosin-stained slides at the invasive front of the tumor to define a low-grade group (BD1) and a high-grade group (BD2 or BD3). RESULTSHigh-grade TB was found in 38.3% of cases, and was associated with pT4, presence of lymphovascular invasion, and tumor relapse (p=0.02, p=0.03, p=0.002, respectively). Patients with highgrade TB showed worse relapse-free survival (RFS) and overall survival (OS) rates than patients with low-grade TB (5-year RFS: High 75.6% vs. Low 92.1%, p=0.001; 5-year OS: High 93.7% vs. Low 93.7%, p=0.001). On multivariate analysis for predictors of RFS and OS, high-grade TB was significant for both RFS and OS (RFS, p=0.003; OS, p=0.005). Patients with high-grade TB experienced lung and liver relapses significantly more frequently than patients with low-grade TB (p=0.03 each). Among patients who received adjuvant chemotherapy (AC), no patients showed lung or liver relapse even in the presence of high-grade TB. CONCLUSIONTB may offer a useful predictor of relapse in patients with stage II colon cancer after surgery, and AC should be considered for patients with high-grade TB.