Is High-Grade Tumor Budding an Independent Prognostic Factor in Stage II Colon Cancer?

BACKGROUND: Risk factors, including lymphatic, vascular, and perineural invasion, are considered indications for adjuvant treatment in stage II colon cancer. However, tumor budding is not included in the above risk factors.OBJECTIVE: This study aimed to assess the value of tumor budding as a prognostic factor in stage II colon cancer. DESIGN: This is a retrospective cohort study.SETTINGS: This study was conducted in a tertiary referral center.PATIENTS: This study examined 1390 patients with stage II colon cancer who received curative resection from 2007 to 2013 at an institution.INTERVENTIONS: These patients were classified according to tumor budding status: low-grade tumor budding (less than 10 buds) and high-grade tumor budding (10 buds or more). Differences between the 2 groups were corrected by propensity score matching.MAIN OUTCOME MEASURES: Disease-free survival and overall survival were the primary end points.RESULTS: Among 1390 patients, 146 (10.5%) had highgrade tumor budding. The high-grade tumor budding group showed adverse histological characteristics such as advanced T stage, histological grade of differentiation, and presence of lymphatic/perineural invasion. After matching, the 5-year disease-free survival rate for the high-grade tumor budding group was significantly lower than for the low-grade group. We also compared survival outcomes according to tumor budding grade for patients who did not have risk factors and did not receive adjuvant treatment. The 5-year overall survival was similar between the 2 groups. However, the 5-year disease-free survival decreased significantly in the high-grade tumor budding group than in the low-grade tumor budding group. LIMITATIONS: This was a retrospective study with a single-center design.CONCLUSIONS: High-grade tumor budding is a poor prognostic factor in stage II colon cancer and is considered one of the risk factors for adjuvant treatment. See Video Abstract at http://links.lww.com/DCR/B962.