| [ Summary ] |
We analyzed 404 cases of colorectal carcinoma (CRC) with submucosal invasion, in order to clarify indications of curative endoscopic mucosal resection (EMR). Histologic subclassification was performed at the deepest invasive tumor margin as follows : well differentiated (M), moder-ately differentiated (M), poorly differentiated (Por). By assessing glandular configurations and cellular arrangements, the M type was further subdivided into two different groups ; moderately -well differentiated (Mw) and moderately-poorly differentiated (Mp), as previously described. Lymph node (LN) metastasis was detected in 43 (11%) of 404 cases, W or Mw lesions showed LN metastasis in 5% (18/330). Mp or Por lesions showed LN metastasis in 38% (25/74) (W/Mw vs Mp/Por ; p<0.01). Of 43 cases with LN metastasis, W or Mw lesions showed no LN metastasis in cases within 1,700 pm submucosal invasion. However, Mp or Por lesions showed LN metastasis even in cases with less than 1,500 /lm submucosal invasion (6/25, 24%, minimum 400 pm submucosal invasion; or minimal invasion). These results revealed that CRC with submucosally massive invasions can be cured bv using EMR, on the condition that the depth of the submucosal invasion is less than 1,500 pm and the histologic grade of the most deeplv invasive portion is W or Mw, with no vessel involvement. Cases of Mp or Por grade can't be cured by using EMR, even if they exhibit characteristically minimal submucosally invasion. |