Colorectal cancer: Nursing

00:00 / 00:00



Colorectal cancer is a malignant tumor that originates in the large bowel, so the colon or the rectum, and is one of the most common types of cancer.

All right, now, the colon has four parts, called the ascending colon, which runs up on the right side of the abdomen; the transverse colon, which runs across the upper part of the abdomen; the descending colon, which runs down the left side of the abdomen; and finally the sigmoid colon, which is the S-shaped part that joins the rectum.

Let’s zoom into the wall of the large intestine, which is made up of four layers. The outermost layer is called serosa or adventitia. Next is the muscular layer, which contracts to move food through the bowel. After that is the submucosa, which consists of a dense layer of tissue that contains blood vessels, lymphatics, and nerves. And finally, there’s the innermost layer, called the mucosa, which consists of simple columnar epithelium spanned by goblet cells. This mucosa forms invaginations called colonic crypts or glands.

Now colorectal cancer occurs when any of these epithelial cells acquire a mutation in the adenomatous polyposis coli or APC genes, which are tumor suppressor genes, meaning that they suppress the growth of tumor cells. This mutation leads to the formation of a small polyp, also called early adenoma. Later on, these polyps may develop further mutations, such as KRAS or p53 gene mutations, leading to the development of colon cancer.

Mutations may arise due to a variety of risk factors. Modifiable risk factors include smoking, obesity, and a diet high in processed meat, and excessive alcohol intake. On the other hand, nonmodifiable risk factors include age above 40, family history of colorectal cancer or colorectal polyps, in addition to hyperinsulinemia and inflammatory bowel disease, including Crohn disease and ulcerative colitis.


Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.