PROFESSOR SAMSUNG MEDICAL CENTER, SUNGKYUNKWAN UNIVERSITY SEOUL, Republic of Korea
Introduction Risk factors, including lymphatic/vascular/perineural invasion, are considered indication for adjuvant treatment in stage II colon cancer. However, tumor budding is not included in the above risk factors. The object of this study was to assess the value of tumor budding as a prognostic factor in stage II colon cancer. Methods This study analyzed 1,390 patients with stage II colon cancer who received curative resection from 2007 to 2013 at an institution. These patients were classified according to tumor budding status: low-grade tumor budding ( < 10 buds) and high-grade tumor budding (≥ 10 buds). Differences between the two groups were corrected by the propensity score matching. Disease free survival and overall survival were the primary end points. Results Among 1,390 patients, 146 (10.5%) had high-grade 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 who and did not receive adjuvant treatment. The 5-year overall survival was similar between the two groups. However, the 5-year disease-free survival decreased significantly in the high-grade tumor budding group than the low-grade tumor budding group. Conclusion High-grade tumor budding is a poor prognostic factor in stage II colon cancer and is considered as one of the risk factors for adjuvant treatment.