The significance of tumor budding in T1 colorectal carcinoma: The most reliable predictor of lymph node metastasis especially in endoscopically resected T1 colorectal carcinoma

Endoscopic resection is widely recognized as a first-line treatment for T1 colorectal cancers (CRC), although additional surgical intervention may be indicated based on the risk of lymph node (LN) metastasis. However, risk factors for LN metastasis in T1 CRC not fully established. We investigated the clinicopathological features of T1 CRC and evaluated their association with lymph node metastasis in 133 cases of T1 CRC, consisting of 87 cases with first-line endoscopic resection (EMR) followed by additional surgery and 46 cases with primary surgical resection. Among the total 133 cases, 16 cases (12.0%) showed LN metastasis; 13 cases (13/16, 81.25%) were included in endoscopic resection cohort. These were all of the non-pedunculated gross type and most of LN(+) tumors invaded submucosa over 1000 μm (surgical cohort vs endoscopic resection cohort; 3 vs 11). However, there was no statistical difference in the depth of submucosal invasion between the LN (+) and LN (−) in both surgical cohort (2799.42 μm ±401.56 vs 3000.00 μm ±721.69, P=.897) and endoscopic resection cohort (2066.55μm ±142.96 vs 2305.77μm ±345.62, P=.520). Conversely, presence of and a higher number of tumor budding foci were associated with an increase in the incidence of LN metastasis in both cohort (P