Everything you need to know about colorectal cancer.

**What is colorectal cancer?** Colorectal cancer, which is one of the most common diseases of the digestive system, starts in the colon or rectum. Depending on where it starts, this cancer is called colon cancer or rectal cancer. The colon and rectum are located in the lower part of the digestive system. When the colon (large intestine) and rectum (rectum) become cancerous at the same time, the term colorectal cancer is used. In order to better understand this issue, it is better to first familiarize ourselves with the structure of the colon and rectum. **colon and rectum** Colon and rectum make up the large intestine. Most of the large intestine is made up of the colon, which is a muscular tube about 1.5 meters long. The different parts of the colon that the food passes through are named as follows (image below): - The first part is the ascending colon, which begins with a sac called the cecum. The ascending colon continues upward on the right side of the abdomen (belly). Undigested food enters the ascending colon from the small intestine. - The second part is called the transverse or middle colon, which is placed from the right side of the body to the left side. - The third part is called the descending colon and it moves down on the left side of the body. - The fourth part of the large intestine is S-shaped and is called the sigmoid colon. The sigmoid colon connects to the rectum and then to the anus. - The ascending and middle parts of the large intestine are together called the proximal colon. Descending and sigmoid colon are also called distal colon. **How do the colon and rectum work?** The large intestine absorbs the water and salt remaining in the food after it has passed through the small intestine (small intestine). The waste material that remains after passing through the large intestine goes to the rectum, which is located at the end of the digestive tract, and is stored there until it passes through the anus. The size of the rectum is 15 cm. The presence of ring-shaped muscles called sphincters around the anus prevent stool from coming out until these muscles relax during defecation. The color image of the digestive system below shows the esophagus, stomach, pancreas, transverse colon, descending colon, sigmoid colon, anus, rectum, appendix, cecum, ascending colon, small intestine, gallbladder and liver. **How does colorectal cancer develop?** Polyps in the colon or rectum can be a sign of colorectal cancer. Most colorectal cancers begin as lumpy growths on the lining of the colon or rectum. These masses are called polyps. Some types of polyps can turn into cancer over time (usually several years), but not all polyps become cancerous. The chance of a polyp turning into cancer depends on the type of polyp. There are different types of polyps: - **Adenomatous polyps (adenoma):** These polyps sometimes turn into cancer. For this reason, adenoma is called a precancerous condition. 3 types of adenoma are: tubular, villous, and villous tubular. - **Hyperplastic polyps and inflammatory polyps:** These polyps are more common, but they are generally not precancerous. Some people with large hyperplastic polyps (more than 1 cm) may need more colorectal cancer screening and colonoscopy. - **Sedentary serrated polyps** **(SSP) and** **Traditional serrated adenomas (TSA)**: These polyps are often treated like adenomas because they increase the risk of developing colorectal cancer. Other factors may increase the risk of developing colorectal cancer, including: - Polyp larger than 1 cm - Presence of more than 3 polyps - Observation of dysplasia after polyp removal

** Read: What is a stomach polyp?**

**Symptoms of Colorectal Cancer** Colorectal cancer may not cause symptoms in the early stages. But the following symptoms can be a sign of colorectal cancer: - Diarrhea or constipation - Feeling that the bowels are not emptying properly. Blood in the stool that makes it appear dark brown or black. - Observing bright red blood from the rectum - Abdominal pain and bloating - Excessive gas production - Feeling full, even when it has been a long time since eating. - Fatigue - Abnormal weight loss - Anemia If your doctor notices symptoms of anemia during a routine medical exam, he may recommend colorectal cancer screening. About 40% of people with this type of cancer are diagnosed when the disease is in its early stages. In general, the symptoms of this disease may be similar to the symptoms of many other diseases. So if you have concerns, you should see a doctor. **initial symptoms** Among people diagnosed with colorectal cancer after reporting symptoms: - 37% of blood is seen in their feces. - 34% have abdominal pain. - 23% have anemia. Among the people who are diagnosed as emergency patients after requesting medical assistance: - 57% of their intestines are blocked. - 25% have stomach lining inflammation. - 18% have holes in their intestines. But some people find out about their disease only in the later stages, when the cancer has spread to the lungs, liver or other parts of the body. Of course, the appearance of symptoms can depend on the affected area. If the cancer spreads to the liver, a person may develop jaundice, which causes the whites of the eyes to turn yellow. If a person has white or light brown skin, it may also appear yellowish. If the cancer affects the lungs, the person may have trouble breathing or cough.

**Read: What is flatulence?**

**Diagnosis of colorectal cancer** A screening test can detect polyps before they become cancerous. It can also detect colon cancer in its early stages, when it is easier to treat. In 80% of cases, a doctor diagnoses colorectal cancer after a colonoscopy because the person has symptoms. Routine screening detects 11% of cases, and in 7% of people with colorectal cancer, they are diagnosed after presenting with abdominal symptoms. The following are the most common and trusted screening methods for colorectal cancer: - **Colonoscopy** Colonoscopy is the standard diagnostic tool for the diagnosis of colorectal cancer. Colonoscopy is a reliable and highly accurate tool that can show the exact location of the tumor. The colonoscope device allows the doctor to see the entire colon and rectum, and they can even remove polyps with this method. A colonoscopy is painless, but for some people a mild sedative is used to help keep them relaxed. Before the colonoscopy, a person may need to drink a laxative liquid to clean out the colon. - **Blood test in stool** This test checks for blood in a stool sample. Of course, fecal blood test can be used for various reasons and it is definitely not a sign of colorectal cancer. - **fecal immunochemistry** Stool immunochemistry tests for occult blood in the lower colon. In this method, a small kit is used to collect a stool sample. - **DNA test** **feces** This test looks for several DNA markers that colon cancers or precancerous polyps shed in the stool. However, it should be noted that this test cannot detect all cancer DNA markers. - **flexible sigmoidoscopy** This procedure involves using a sigmoidoscope, a flexible, thin, lighted tube, to examine the rectum and sigmoid colon, the last part of the colon before the rectum. The test takes a few minutes and is not painful, but it may be uncomfortable. - **X-ray barium enema (Barium enema X-ray)** Barium is a contrast dye that can show any abnormal features on an X-ray. A health care professional will introduce it to it. Your doctor may recommend a colonoscopy for a more detailed examination after a barium enema X-ray. - **CT colonography** In this method, images of the large intestine are taken. Of course, if a mass is seen in this method, the person needs a colonoscopy. - **imaging scan** An ultrasound, CT scan, or MRI can show whether the cancer has spread to another part of the body.

**Can colon cancer be prevented?** There is no surefire way to prevent colorectal cancer. But you can reduce the risk of contracting this disease by doing the following: - **Colorectal cancer screening** From the time the first abnormal cells begin to grow into polyps, it usually takes about 10 to 15 years for them to develop into colon cancer. With regular screening, most polyps can be found and removed before they become cancerous. Screening can also detect colon cancer in its early stages, when it is small and easier to treat. If you are 45 years or older, it is better to get a colorectal cancer screening. Also, if you have a family history of colorectal polyps or cancer, talk to your doctor about it. - **physical activity** Being overweight or obese increases the risk of colon cancer in both men and women, but the association appears to be stronger in men. Maintaining a healthy weight can help reduce the risk of developing this disease. Being more active reduces the risk of colorectal cancer and polyps. Regular moderate to vigorous activity can reduce this risk. - **diet** In general, diets high in vegetables, fruits and whole grains and low in red and processed meat are likely to reduce the risk of colon cancer, although it is not clear exactly which factors are important. Many studies show that there is a relationship between the consumption of red meat (beef and lamb) or processed meat (such as hot dogs, sausages and hamburgers) with an increased risk of colon cancer. In recent years, some large studies have shown conflicting evidence that dietary fiber may reduce the risk of colon cancer. Research in this field is still ongoing. However, recent studies looking specifically at whole grain consumption suggest that adding whole grains to the diet can reduce the risk of colorectal cancer. Limiting red and processed meat and eating more vegetables, fruits, and whole grains may help reduce risk. - **not smoking** Long-term smoking is associated with an increased risk of colon cancer, as well as many other cancers and health problems. - **vitamins, calcium and magnesium** Some studies suggest that taking a daily multivitamin containing folic acid or folate may reduce the risk of colon cancer. Some studies have shown that vitamin D, which you can get from sun exposure, in certain foods, or in vitamin pills, may reduce the risk of colon cancer. Studies have shown that low levels of vitamin D are associated with an increased risk of developing colorectal cancer as well as other cancers. Because of concerns that excessive sun exposure can cause skin cancer, most experts do not currently recommend this method as a way to reduce the risk of colon cancer. It's best to talk to your doctor about whether your vitamin D levels should be tested. Low levels of calcium in the diet have been linked to an increased risk of colorectal cancer in some studies. Some studies suggest that increased calcium intake may reduce the risk of colon cancer. Taking calcium and vitamin D may work together to reduce the risk of colon cancer, because vitamin D helps the body absorb calcium. Several studies suggest a possible link between a magnesium-rich diet and a reduced risk of colorectal cancer, particularly among women. - **non-steroidal anti-inflammatory drugs** Many studies have shown that people who regularly take aspirin or other non-steroidal anti-inflammatory drugs such as ibuprofen and naproxen have a lower risk of developing colorectal cancer and polyps. But taking aspirin and other non-steroidal anti-inflammatory drugs can cause serious or even life-threatening side effects, such as bleeding from gastric irritation or peptic ulcers, which may outweigh the benefits of these drugs. Because aspirin or other NSAIDs can have serious side effects, consult your doctor regularly before starting any of them. - **Hormone replacement therapy for women** Some studies have shown that taking estrogen and progesterone after menopause (sometimes called menopausal hormone therapy or combined hormone replacement therapy) may reduce the risk of colorectal cancer in women. Because taking estrogen and progesterone after menopause can also increase a woman's risk of heart disease, blood clots, and breast and lung cancer, it's not usually recommended just to reduce the risk of colon cancer. If you are considering using menopausal hormone therapy, be sure to discuss the risks and benefits with your doctor. **Dietary actions that can reduce the risk of colorectal cancer** - Eat lots of fiber, fruits and vegetables - Eating quality carbohydrates - Limit consumption of red and processed meat - Healthy consumption such as avocado, olive oil, fish oil and nuts instead of saturated fat

**The last word is…** Colorectal cancer is a common type of gastrointestinal cancer. Treatment in the early stages of the disease can remove cancer cells and increase the chance of treatment. However, symptoms of this disease may not appear until it progresses to later stages. Anyone who is at risk of developing colon cancer should see a doctor for screening. Regular screening increases the chances of early detection of this disease.

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