| Along with the popularity of mass screening program, the number of early colorectal cancer, especially AJCC Tis and T1 cancers, increase substantially in recent years. Detection and treatment of these early cancerous lesions are extremely meaningful in several aspects. Firstly, it can provide biggest survival benefits for the patients and maximize the effectiveness of the whole screening program. Secondly, these early cancers are not only curative but also manageable with endoluminal procedures such as EMR or ESD. Thirdly, the endoluminal treatment can, if appropriately applied, provide the opportunity of curative resection that is comparable to surgical resection with a shorter period of hospitalization, lesser cost and probably favorable gain in quality of life. Nevertheless, T1 cancers still carry the risk of regional lymph node metastasis thus how to discriminate tumors with and without the risk of LN metastasis becomes an important issue and also a big challenge for the clinicians. Existent imaging modalities, such as CT scan or PET, are also not sufficiently sensitive to detect regional LN metastasis. Previous studies have shown that some pathological characteristics are predictive of regional LN metastasis (i.e. invasive depth, lymphatic or vascular invasion, etc.) and any endoscopic modality that can well correlate with such pathological findings is considered as helpful for in vivo diagnosis and decision making during the procedure. There exist several tools such as image-enhanced endoscopy and magnifying endoscopy that enables discrimination of high-risk T1 cancers with low-risk ones with high-accuracy. Before standardization of this approach, there remain several challenges. Long-term outcome research regarding endoluminally resected T1 cancers and cost-effectiveness analysis comparing endoluminal and surgical treatments are the most needed future studies to determine the optimal treatment for colorectal T1 cancers. |
