A review on current endoscopic risk management of early colorectal carcinoma (T1) and Western perspectives on endoscopic and surgical resection methods was published in Digestive Endoscopy.
Colorectal cancer (CRC) is a commonly diagnosed cancer in the United States, and the rate of early invasive CRC will increase within the next decade. Early low-risk CRC is defined as well or moderately differentiated adenocarcinoma with the absence of vascular invasion, ≤1000 μm depth of submucosal invasion. The review authors provide the following insights into the management of CRC.
Malignant colorectal polyps: Majority of patients with T1 CRC do not experience metastasis. Moreover, most of T1 CRC can be successfully treated with polypectomy only. Polypectomy can result in high tumor-free and tumor-related survival if radial resection is offered immediately.
Colorectal neoplasia morphology: Real-time prediction of dysplasia and invasive carcinoma are important endoscopic skills. The 2 systems used to classify neoplasia are the Paris classification, which macroscopically stratifies neoplasia into polypoid, nonpolypoid, and excavated or ulcerated lesions, and the Kudo classification which distinguishes non-neoplastic from neoplastic lesions of the mucosal pit pattern.
Lymphatic spread of CRC: The width of cancer invasion, instead of its depth, correlates with increased access to the lymphatic system and, subsequently, higher risk of lymph node metastasis.
Histological invasion depth: Models that classify CRC invasion depth include the Haggitt classification for pedunculated lesions and the Kikuchi classification for sessile or flat lesions.
Size and location of colorectal early cancer: Invasive carcinoma was reported only for colorectal polyps >5 mm in size, with increasing risk to 38.5% for neoplasia >10 mm and 78.5% for neoplasia >42 mm. In terms of location, neoplasia in the rectum have a
greater malignant transformation rate compared with those in the remaining colon, and are an independent risk factor for lymph node metastasis.
Impact of resection margin for early CRC: Polypectomy resection margin <1 mm of malignant polyps was associated with residual cancer in 16% on colectomy specimens
Additional high-risk features of CRC: High risk features include tumor budding, cribriform-type structural atypia, β-catenin and E-cadherin.
Endoscopic ultrasonography and magnetic resonance imaging tumor (T) and lymph node (N) staging in CRC: Rectal endoscopic ultrasound (EUS) and pelvic magnetic resonance
imaging (MRI) are modalities for preoperative staging of rectal cancer. EUS and MRI achieve comparable sensitivity and specificity for T-staging.
Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD): Both endoscopic mucosal resection and dissection of neoplasia are important concepts. Current mainstay treatments differ substantially, with an EMR-focused approach in the Western hemisphere, while ESD is a well-established technique in the Eastern hemisphere.
Treatments of CRC include endoscopic full-thickness resection, trans-anal full-thickness resection and radiation therapy. The goal of T1 CRC surveillance following curative endoscopic or surgical resection is detection of recurrent cancer and metachronous lesions. Current surveillance guidelines in the United States recommend colonoscopy within 1 year following surgery, with a subsequent colonoscopy every 3-5 years. Future research includes information on the utility of adjuvant chemoradiation or chemoradiation alone for high-risk early rectal cancer.
Bartel MJ, Brahmbhatt BS, Wallace MB. Management of colorectal T1 carcinoma treated by endoscopic resection from the Western perspective. Dig Endosc. 2016; 28: 330–341