[이데일리 이순용 기자] The large intestine is divided into the colon and rectum. The round part of the question mark is the colon, and the lower straight part is the rectum. The rectum is the part in front of the large intestine to the anus and it stores faeces and controls faeces. It is about 15 cm long.
The rectum is located in the middle of a narrow pelvis the size of a fist. The front is adjacent to the genital organs such as the prostate or vagina, the side is adjacent to the blood vessels and nerves of the pelvis, and the back is the sacrum. . Therefore, rectal cancer easily metastasizes to other nearby organs, and unlike colon cancer, the recurrence rate and the possibility of complications due to surgery are high.
Song Joo-myung, professor of colorectal surgery at Incheon St. Hospital emphasized. Mary at the Catholic University of Korea, “Since rectal cancer usually has no symptoms in its early stages, it is often discovered incidentally during examinations. As with other cancers, early detection and treatment are most important.”
◇ Colon and rectal cancer, 3rd in terms of number of cases and deaths… Rectal cancer accounts for 40% of colorectal cancers
According to the national cancer statistics released at the end of last year, the number of new colorectal cancer patients in 2020 was 27,877, the third highest after thyroid cancer (29,180) and lung cancer (28,949). This is 4th in the overall cancer incidence rate in 2019, surpassing stomach cancer and rising one notch.
Colorectal cancer also has a high mortality rate. According to the Office for National Statistics, a total of 8,984 people died from colorectal cancer in 2021, coming third after lung cancer (18,902) and liver cancer (10,255). It accounts for 10.9% of all cancer deaths (82,688). This means that 1 in 10 cancer deaths will result from colorectal cancer.
Most colorectal cancers are caused by the growth of polyps in the large intestine. Therefore, if you remove only the polyps well, you can effectively prevent colon cancer. The incidence rate is said to be reduced by 70-90% and the death rate by around 50%. In particular, it is known that the larger the size of the polyp, the greater the possibility of transition to cancer. The incidence rate increases with age, but it occurs mainly in people over 50 years of age.
Around 80% of colorectal cancer is influenced by acquired and environmental factors such as eating habits and obesity. The remaining 10-20% is genetic. In particular, eating habits are known to be acquired factors that have the greatest influence on the incidence of colorectal cancer. Obesity and alcohol consumption double the risk of colorectal cancer. Smoking is known to increase by 50%. It is estimated that around 1 in 5 colorectal cancer patients are smoking related.
Professor Joo-Myung Song said, “Fortunately, more than 90% of colorectal cancer can be cured by regular endoscopy through early detection, and the 5-year survival rate is over 75%.”
Rectal cancer accounts for around 40% of all colorectal cancers. Before the 2000s, there were more patients with colon cancer than colon cancer, but the rate of rectal cancer continues to decrease due to western eating habits. Considering that the rate of colon cancer in developed countries such as the United States is about 70%, the incidence rate of rectal cancer in Korea is expected to decrease further in the future.
◇ Regular colonoscopy recommendation after age 45… See a doctor if your bowel habits change
The risk of colorectal cancer is higher if you are over 50 or if you eat a lot of red meat but not vegetables or fruit. Also, those who are obese, drink, or smoke should be careful of colon and rectal cancer. Be careful if you have rectal or colorectal cancer in your family, or if you have bowel disease such as inflammatory bowel disease or familial polyposis.
Colon cancer can cause a variety of symptoms. As the rectum narrows due to cancer, the inability to pass stool is sometimes mistaken for constipation, and stools come out thin or diarrhoea. The back also feels heavy. There may be blood or mucus in the stool. However, these symptoms need to be differentiated as most of these symptoms are not only symptoms of rectal or colorectal cancer, but can also be caused by other rectal diseases.
If symptoms are suspected and a hospital visit is made, the first examination is carried out through an anorectal examination and an anorectoscope. Then, as soon as possible, the remaining rectum and colon are examined by colonoscopy to determine the presence or absence of rectal cancer. If rectal cancer is found, a CT (computed tomography) or pelvic MRI (magnetic resonance imaging) is performed to check for metastases to other organs. In the case of rectal cancer, there is a possibility of lung metastases, so a chest CT is also essential.
In the case of early rectal cancer, surgery is performed after CT and MRI before surgery after diagnosis, but in advanced cases, radiation chemotherapy must be performed before surgery. Radiation chemotherapy before surgery takes about a month and a half. Surgery is performed 6 to 8 weeks after completion of radiation therapy.
Professor Joo-Myung Song said, “The Korean Society of Colon and Anology recommends regular colonoscopy after the age of 45 for the early detection of colorectal cancer, and conducts fecal occult blood tests as part of’ r national cancer screening programme.” You should go immediately. to hospital and get tested without delay.”
◇ Surgery is the only cure… NGS enables personalized cancer treatment
For rectal cancer, surgical resection is the only cure. The most common surgical procedure is a low anterior resection. There is adipose tissue surrounding the rectum, and cancer cells can spread within this adipose tissue. A low anterior resection removes the rectum and surrounding adipose tissue from the pelvis while minimizing damage to this adipose tissue. performed laparoscopically. Some early rectal cancers are treated with colonoscopy or transrectal resection.
For advanced rectal cancer, radiation chemotherapy is often required before surgery. For rectal cancer, except stage 1, surgery is followed by chemotherapy or radiation therapy.
Recently, personalized cancer treatment for each patient has been implemented through Next Generation Sequencing (NGS) gene panel tests. The NGS test analyzes the patient’s genome sequence to diagnose diseases caused by genetic mutations and help choose the right treatment for each individual. In addition, by immediately analyzing genetically mutated regions of colorectal cancer through NGS testing, treatment (drug) response can be predicted through less examination time or personalized treatment, helping to increase impact the treatment.
Professor Joo-Myung Song said, “The recurrence rate of rectal cancer is higher than other colorectal cancers, and because it is a cancer that occurs in a narrow pelvis, the local recurrence rate is also high.” It has decreased significantly,” he said.
◇ Eating and exercise habits are important for preventing… Avoid red and processed meat, avoid alcohol and smoke
Diet and exercise are important to prevent colorectal cancer. Red meat, such as pork and beef, and processed meat, such as ham and sausage, should be avoided as much as possible. Regular exercise can reduce the incidence of cancer by promoting intestinal peristalsis and reducing the time faeces stay in the intestines. Obesity also increases the risk of colorectal cancer. Smoking and drinking are also linked to cases of colon and rectal cancer, so it is good to stay away from cigarettes and alcohol.
Most importantly, you should have a colonoscopy at least once after the age of 45. The Colonoscopy Association recommends a colonoscopy every 5 years after the age of 45. This is because the incidence of colorectal cancer is high after the age of 50, and it is very likely to be found in a polyp (pre-cancerous) state which can be easily resected by endoscopic resection .
Professor Joo-Myung Song said, “As we age, as we age, the number of spots and age spots on our face increases, and polyps increase in the large intestine, increasing the possibility of developing cancer.” After the age of 45, a colonoscopy is recommended.”