Endoscopic Treatment of Early Cancer of the Colon

Abstract

Colorectal cancer is the fourth most common cancer diagnosis worldwide and the second leading cause of cancer death. In the United States, it is estimated that in 2015 there will be 132,700 new cases of colorectal cancer (representing 8.43% of all new cancer cases) and 49,700 deaths. Colonoscopy plays a fundamental role in the prevention and management of colorectal cancer patients and is used for both the diagnosis and treatment of early colorectal cancer and its precursors. Improvements in colonoscopy preparation, new techniques of adenoma detection, and recent progress in endoscopic imaging methods are providing higher-quality results and reducing the incidence and mortality of the disease. Traditionally, colonoscopy has been used to remove precursor lesions. Invasive cancer was treated by surgical resection with or without chemoradiotherapy. During the past decade, endoscopic resection techniques have advanced, and cancers confined to the mucosal and superficial submucosal layers can now be resected via flexible endoscopes. Therefore, it is important to understand the indications and limitations of endoscopic resection, determine whether the cancer can be curatively resected, and assess the risk of lymph node metastasis, which precludes endoscopic treatment.

Keywords: Colon cancer; adenoma; colonoscopy; endoscopic mucosal resection; endoscopic submucosal dissection; resection.

Figure 1

A schematic representation of the Paris classification for mucosal neoplasia. Lesion morphology helps in the evaluation of the risk of invasive disease and guides the approach to endoscopic resection. Advanced mucosal neoplasias are broadly divided into protruded, flat elevated, and flat morphologies. Protruded lesions rise more than 2.5 mm above the surrounding mucosa and include pedunculated (0-Ip), subpedunculated (0-Isp), and sessile (0-Is) lesions. Flat elevated lesions (0-IIa) rise less than 2.5 mm above the surrounding mucosa, and features such as central depression (0-IIa + c) or a broad-based nodule (0-IIa + Is) have been described. Flat lesions include barely perceptible elevation (0-IIb), depressed (0-IIc), and excavated (0-III) types.

Figure 2

Kudo pit pattern classification of colorectal polyps.

Figure 3

Examples highlighting typical features of the Narrow-Band Imaging International Colorectal Endoscopic criteria: color (A), vessels (B), and surface pattern (C).

Figure 4

Visualization of a scar at an endoscopic mucosal resection site 3 months after the procedure showing no residual neoplasia (A) and residual adenoma (B).