Table 2.
Lymph node micrometastasis characteristics of the included studies
| Ref. | Depth of tumor invasion | Method | Antibody | Definition of micrometastasis | LNs (n) | Average LNs (n) |
| Cai et al[18], 2000 | T1b | IHC | CK (CAM5.2) | pN0 by HE staining | 1945 | 25.0 |
| Fukagawa et al[19], 2001 | T2-T3 | IHC | CK (AE1/AE3) | pN0 by HE staining | 4484 | 41.9 |
| Choi et al[20], 2002 | T1b | IHC | CK (AE1/AE3) | pN0 by HE staining | 2272 | 25.8 |
| Lee et al[21], 2002 | T1-T4 | IHC | CK (35βH11) | pN0 by HE staining | 3625 | 23.7 |
| Yasuda et al[22], 2002 | T2-T3 | IHC | CK (CAM5.2) | pN0 by HE staining | 2039 | 31.9 |
| Morgagni et al[23], 2003 | T1 | IHC | CK(MNF 116) | pN0 by HE staining | 5400 | 18.0 |
| Yonemura et al[24], 2007 | T1-T4 | IHC | CK (AE1/AE3) | ≤ 0.2 mm | 12012 | 39.0 |
| Kim et al[25], 2008 | T1-T3 | IHC | CK (AE1/AE3) | pN0 by HE staining | 4990 | 27.1 |
| Ishii et al[26], 2008 | T1b-T2 | IHC | CK (O.N.352) | pN0 by HE staining | 1028 | 29.4 |
| Kim et al[27], 2009 | T1 | IHC | CK (AE1/AE3) | ≤ 2 mm | 3526 | 39.2 |
| Wang et al[28], 2011 | T1-T3 | IHC | CK (AE1/AE3) | > 0.2 mm and ≤ 2 mm | 4202 | 22.0 |
| Jeuck et al[29], 2015 | T1-T4 | IHC | CK (KL1) | pN0 by HE staining | 2018 | 21.2 |
IHC: Inmmunohistochemistry; CK: Cytokeratin; pN0: Node-negative; HE: Hematoxyline-eosin; T1: Tumor invades lamina propria, muscularis mucosae or submucosa; T1a: Tumor invades lamina propria or muscularis mucosae; T1b: Tumor invades submucosa; T2: Tumor invades muscularis propria; T3: Tumor penetrates subserosal connective tissue without invasion of visceral peritoneum or adjacent structures; T4a: Tumor invades serosa (visceral peritoneum); T4b: Tumor invades adjacent structures.