The cecum is the beginning of the colon where the small intestine empties into the large intestine. The ascending colon, transverse colon, descending colon, sigmoid colon, and rectum are other parts of the colon after the cecum.The colon ends at the rectum and waste exits through the anus.denocarcinoma is a type of cancer that starts in the cells that form glands making mucus to lubricate the inside of the colon and rectum. This is the most common type of colon cancer.