Colorectal cancer is the third most common cancer in men worldwide. Colorectal cancer is a type of cancer that affects the large intestine and/or the rectum, depending on where the cancer cells are found.
Colorectal Cancer (CRC) Awareness Month is commemorated in March to make men and women aware that colorectal cancer can affect both men and women, and that the early signs can be difficult to detect, but above all everything, that it is preventable.
Understanding our body
Knowing the affected parts better will help us better understand the disease. Colorectal cancer affects two fundamental regions: the colon and the rectum . Both are parts of the gastrointestinal system and make up important parts of the large intestine. Specifically, the colon, a muscular tube approximately 1.5 meters long, makes up most of the large intestine. The portions of the colon are named for the direction in which food passes. It is divided into two sections: the proximal colon and the distal colon, or ascending colon and descending colon. Basically they are different denominations for “the first portion of the colon and the second”, the latter being the closest to the rectum.
After passing through the small intestine, the colon absorbs water and salt from leftover food (small intestine). The residues that remain after passing through the colon are deposited in the rectum, which is the last 15 cm of the digestive tube. It stays there until it’s time to go through the anus. Ring-shaped muscles around the anus (also called sphincters) keep stool from coming out until it loosens during a bowel movement.
What is colorectal cancer?
Colorectal cancer begins in at least one of the two areas discussed (the colon or the rectum). Depending on where it starts , this disease is called colon cancer or rectal cancer. Because they have many similar features, colon cancer and rectal cancer are sometimes combined together. Most colorectal cancers begin as a polyp , a growth of tissue on the inner lining of the colon or rectum.
Some polyps can become cancerous over time (usually many years), however, not all polyps become cancerous . The chance of a polyp turning into cancer is determined by the type of polyp.
If the cancer develops in a polyp, it can eventually spread to the wall of the colon or rectum. The walls of the colon and rectum are made up of many layers. Colorectal cancer begins in the inner layer and can spread to all or part of the other layers. Cancer cells can spread into the bloodstream or lymphatic vessels once they have penetrated the wall. They can then travel to neighboring lymph nodes or even other regions of the body.
Colorectal Cancer Screening
Screening is a procedure that checks for cancer before a person has any symptoms . This can help detect cancer at an early stage. It may be easier to treat aberrant tissue or cancer if it is found early. This is so because the cancer may have already spread by the time symptoms appear.
There are researchers trying to find out who is more likely to develop certain types of cancer. They also look at what we do and what we expose ourselves to, to determine if it makes us more likely to get some type of cancer. This data helps doctors determine who should be screened, which screening tests should be used to prevent which type of cancer, and how often they should be done.
Types of detection methods
With the advancement of technology, many screening techniques are used to detect colorectal cancer. Even the presence of blood in the stool is a potential marker, although it is not a confirming sign.
- colonoscopy
During a colonoscopy, the patient is (usually) sedated and the doctor examines the entire rectum and colon. A colonoscopy is a flexible, lighted tube that is inserted into the rectum and throughout the colon to check for polyps or cancer. The doctor may remove polyps or other tissue for inspection during this operation. If the polyp is removed or removed, it helps prevent colorectal cancer.
- Computed Tomography Colonography (CT Colonography)
Computed tomography-colonoscopy (CT-colonoscopy), also known as virtual colonoscopy , is a screening procedure that is currently being investigated . For best results, it should be interpreted by a trained radiologist. CT colonography may be an alternative for people who cannot have a standard colonoscopy because of the risk of anesthesia (medication that blocks awareness of pain) or who have a blockage in the colon that prevents a full exam.
- Fecal occult blood test
This is the jewel in the crown when it comes to screening and prevention. The fecal occult blood test looks for blood in the stool (often microscopic, that is, not visible to the naked eye), which could indicate various pathologies such as polyps, hemorrhoids, gastric or small intestinal ulcers, an anal fissure or, sometimes, cancer (among other possibilities). A positive result, therefore, does not give us a diagnosis. Even eating a rare steak could alter the results. However, a positive result can be a signal to investigate a little more…
The two types of tests available are guaiac (FOBT) and immunochemical (FIT). Because polyps and neoplasms do not bleed regularly, FOBT must be performed on many stool samples per year and repeated each year.
Who should undergo screening tests?
Ok, surely the importance of screening and prevention has already become clear to you, but who is this screening mainly aimed at? Mainly to those groups with an increased risk, such as people with a family history of colon or rectal cancer. Patients who are also at personal risk of developing colorectal cancer should be screened. There are different screening options for different cases. People with a history of IBD (irritable bowel disease) or Lynch syndrome, etc., should have a colon-rectal screening to check the possibilities.
Although the specific recommendations may vary slightly between countries, in Spain screening using the fecal occult blood test is performed every 2 years on all people over 50 years of age, even if they are asymptomatic and have no family history. In the group of people at risk, the test and the cadence of the tests depend on each particular case and the specific risk, being able to resort to a colonoscopy every 10 years, among other possibilities.
References
What is colorectal cancer – American cancer society- https://www.cancer.org/cancer/colon-rectal-cancer/about/what-is-colorectal-cancer.html#:~:text=Colorectal%20cancer%20starts%20in%20the,to%20grow%20out%20of%20control.Colorectal cancer – NCI – https://www.cancer.gov/types/colorectalColorectal screening – https://www.cancer.net/cancer-types/colorectal-cancer/screeningColorectal Cancer screening-Patient version – NCI – https://www.cancer.gov/types/colorectal/patient/colorectal-screening-pdq
