Malignant Tumors in the Colon

Abstract

Cancer of the colon and rectum (colorectal cancer (CRC)) is the third most common cancer in men and the second in women and major cause of cancer-related mortality worldwide. The main histologic types of CRC are adenocarcinomas, and other histologic types, such as signet ring cell carcinoma, squamous cell carcinoma, adeno-squamous carcinoma, small-cell carcinoma, medullary carcinoma, and undifferentiated carcinoma, are very rare. Early colorectal cancer is defined as cancer cells confined to the mucosal or the submucosal layer regardless of lymph node metastasis. Advanced colorectal cancer is defined as cancer cells invaded proper muscle layer or deeper. Superficial submucosal cancer is a candidate for endoscopic resection because it has a limited risk of lymph node metastasis. Therefore, preoperative endoscopic evaluation of the exact depth of invasion is important to decide proper therapeutic strategy in early CRC. Malignant tumors other than adenocarcinoma rarely originate in the colon, and metastatic cancer is less than 1% of total colorectal malignancies.