The most important factor which predicts the probability of metastasis in early-stage cancers of the colon is the depth of cancer invasion. The probability of lymph node metastasis is minimal if cancer invasion is limited to within the mucosal layer. For superficial-type cancers, the size of the lesion is not as important as the depth of invasion in determining the risk of lymph node involvement. Large superficial tumors, so-called “laterally spreading tumors” (LST), in the colon have little tendency to vertical growth despite their lateral extension. Therefore, they are best removed by endoscopic mucosal resection (EMR). To ensure the curativeness of the EMR, accurate histopathologic assessment of the resected specimens is essential, because a significant amount of submucosal invasion of the tumor suggests considerable risk of lymph node metastasis, which necessitates additional surgery.
The objectives of performing endoscopic submucosal dissection (ESD) are to ensure reliable en bloc resections of superficial neoplastic lesions and to confirm the completeness of the resection with an accurate histopathologic assessment. ESD offers a reliable and curative treatment with minimum invasiveness.
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