Spotlighting Colorectal Cancer

Cancer is known to form on basically any organ or body part, whether it be skin, eyes, mouth, even bone cancer is a rare but existing type of cancer. With March being Colorectal Cancer Awareness Month, this article will be dissecting colorectal cancer and advocating for an increase in research in this type of cancer.

Colorectal cancer, or colon cancer, is the cancer of the colon or rectum, which are organs of the large intestine. The colon is one of the last organs of the digestive system, absorbing water and salt from remaining food matter after being processed by the small intestine. The waste after this goes through the 6-inch rectum and is stored until it passes through the anus to be excreted (cancer.org). Symptoms of colorectal cancer can include abdominal cramps, fatigue, iron deficiency, changes in bowel behavior, and weight loss.

Colorectal cancer is the third most common cancer worldwide and accounts for around 10% of all cancer cases, making it the global second leading cause of cancer-related deaths (WHO). Experts predict that by 2040, the annual number of colorectal cancer cases will increase by 63% (3.2 million new cases per year), and the annual number of deaths will increase by 73% (1.6 million deaths per year) (WHO). To lessen this horrific prediction for the outcome of colorectal cancer, we can help raise awareness, fund research projects actively bettering diagnostic and treatment methods, and ensure that those with the condition are supported.

Manifestation

Most colorectal cancers start with polyps on the inner lining of the colon or rectum, which are small noncancerous growths that develop on the lining of organs. Polyps themselves are common as one ages; however, some polyps can change into cancer over time, which is why it’s important for early diagnosis and monitoring of a polyp. A polyp can be more likely to lead to cancer if it’s larger than 1 centimeter, if more than 3 polyps are present on someone, and if the polyp cells look abnormal. With that being said, there are three types of polyps. Adenomas are specifically called a precancerous condition, with tubular adenomas being the most common type, and villous adenomas being the least common but having a greater chance of changing into cancer. Hyperplastic polyps and inflammatory polyps, in contrast, are usually not precancerous and are more common. Finally, sessile serrated polyps and traditional serrated adenomas have a higher risk as well of becoming cancerous.

After polyp formation, the polyp can grow into the wall of the colon/rectum, starting in the innermost layer of intestinal tissue (mucosa), and spreading outward to the thick muscle layers, subserosa, and serosa. Now, in the wall, these cancer cells can infect blood vessels and lymph vessels and spread to the rest of the body.

Risk Factors

As for how colorectal cancer risk can be enhanced, there are certain factors that make one more likely to get colorectal cancer. These factors include:

• Age: Most cases occur in individuals over 50 years old

• Genetics: Colorectal cancer has been linked to inherited gene mutations in some studies, but there is also evidence for most cases occurring due to acquired gene mutations. Those who may have a higher predisposition for colorectal cancer include:

  • Familial adenomatous polyposis, attenuated FAP, and Gardner syndrome, which all are caused by inherited changes causing the repression of the tumor suppressor gene APC, allowing polyp formation. 

  • Lynch syndrome is caused by mutations in DNA repair genes that may allow errors in DNA to affect growth-regulating genes. 

• Environmental Factors: These include unhealthy lifestyle choices like sedentary behavior, obesity, smoking and alcohol addiction, and an unhealthy diet.

Prevention and Treatment

As a result, lifestyle changes are the most one can do to prevent colorectal cancer, but, like stated earlier, early diagnosis and monitoring of polyps can ensure doctors are able to treat a polyp that has become malignant as soon as possible.

Thus, caring for early-stage disease and advanced disease differs. For early-stage colorectal cancer, which is defined as the tumor being limited to the bowel region, surgery is used to remove the tumor. Procedures vary based on location, but typically the removal of a portion of either the colon or rectum is done, followed by adjuvant therapy like chemotherapy. Radiation therapy can also be done to reduce the size of the tumor in the rectum.

In terms of an advanced disease, this is defined by the cancer becoming metastatic, meaning it has spread to other organs. Chemotherapy is used first to kill cancer cells, and immunotherapy drugs can be prescribed depending on if the tumors show genetic markers. Surgery can possibly also be used to remove tumors that are heightening symptoms. 

Written By: Shreeya Lalam

---

Works Cited

What is colorectal cancer? | How does colorectal cancer start? (n.d.). American Cancer Society. https://www.cancer.org/cancer/types/colon-rectal-cancer/about/what-is-colorectal-cancer.html

World Health Organization: WHO & World Health Organization: WHO. (2023, July 11). Colorectal cancer. https://www.who.int/news-room/fact-sheets/detail/colorectal-cancer

Causes of colorectal cancer | Is colon cancer hereditary? (n.d.). American Cancer Society. https://www.cancer.org/cancer/types/colon-rectal-cancer/causes-risks-prevention/what-causes.html