This type of cancer is formed from the cells of the large intestine - the lower part of the digestive system.

Cancer of the rectum occurs in the terminal part of the intestine.

In Western literature, colon cancer and rectal cancer combine under the general concept of "colorectal cancer".

Most cases of colon cancer begin with small benign nodules called adenomatous polyps. Over time, some of these polyps are converted to colon cancer. Polyps can be very small and do not give any symptoms. For this reason, it is recommended that people who are predisposed to have regular screening for colon cancer and precancerous conditions.

Causes of colon cancer.

In most cases, the cause of cancer remains incomprehensible. Cancer occurs when normal intestinal cells mutate, acquiring the properties of malignant. First, polyps can be formed that exist in the intestines for years, without manifesting themselves in any way. But once these cells turn into cancer.

Precancerous formations in the intestine.

Bowel cancer often begins with polyps on the inner shell of the intestine. Polyps in shape can resemble fungi. Precancerous growths of cells can also be flat or recessed into the intestinal wall (non-lipoid formations). Timely detection and removal of these formations can prevent bowel cancer.

Genetic mutations that increase the risk of colon cancer.

Hereditary genetic mutations that are associated with colon cancer can be transmitted through many generations. But these cases constitute only a small part of all cancers. Hereditary mutations do not make colon cancer unavoidable, but significantly increase the risk.

Syndromes associated with colon cancer include:.

• Family adenomatous polyposis. This is a rare disease that causes the formation of thousands of polyps on the inner surface of the large intestine. People with this syndrome have a high risk of cancer, especially after 40 years.

• Hereditary nonpolyposis colorectal cancer (HNPCC or Lynch syndrome). In Lynch syndrome, patients at risk of several types of cancer, including cancer of the large intestine. The tendency to develop cancer is observed after 40-50 years.

Both of the above syndromes can be detected in genetic screening. If you are concerned about your family history, talk with your doctor about the conduct of genetic tests.

Risk factors for colon cancer:.

Elderly age. According to American doctors, about 90% of patients with colon cancer are people over 50.

Race. Black-skinned immigrants from Africa and North American Indians have a higher risk of colon cancer than those of other races.

Previously transferred colorectal cancer or polyps. If a person already had such a disease, the risk of cancer in the future is significantly increased.

Inflammatory bowel disease. Chronic inflammatory diseases, such as ulcerative colitis (NJC) and Crohn's disease, contribute to the degeneration of intestinal cells.

Hereditary syndromes with risk of colon cancer. This includes Lynch syndrome and familial adenomatous polyposis.

Weighed down family history. The risk of colon cancer is significantly increased if they were hurt by your parents, brothers or sisters. In some cases this is due to genetic predisposition. In other cases - with carcinogens from the environment or harmful lifestyle.

Inadequate nutrition. A diet that contains a lot of fat and insufficient amounts of fiber, predisposes to colon cancer. Some researchers have identified a link between colon cancer and excessive red meat consumption.

Passive lifestyle. A low-active, sedentary lifestyle contributes to impaired bowel function, and increases the risk of cancer. Regular physical workouts help to overcome this risk factor.

Diabetes. Patients with diabetes and insulin resistance have an increased risk of colon cancer.

10. Obesity. According to statistics, people with obesity suffer from colon cancer more often people with a healthy body weight. In addition, they have a higher mortality from this type of cancer.

eleven. Smoking. Some studies show that smokers are more prone to colon cancer, as well as several other cancers.

12. Alcohol. Severe alcohol abuse damages the intestines and increases the likelihood of malignant cell degeneration.

13. Radiation therapy of cancer. Tumor irradiation, which was directed to the abdominal region, promotes mutations in intestinal cells and the appearance of cancer.

Symptoms of colon cancer.

Many patients with colon cancer at an early stage of the disease do not experience any symptoms. The time of appearance of the first signs of the disease depends on the location and size of the tumor.

Symptoms include:.

• Constipation or diarrhea.

• Changing the consistency of the stool.

• Occurrence of traces of blood in the stool.

• Severe rectal bleeding.

• Constant cramping, abdominal pain.

• Increased gas formation.

• Feeling of incomplete bowel movement.

• Unexplained weight loss.

• Weakness and fatigue.

When should I see a doctor?.

If you have weight loss, abdominal pain, stools and blood in the stool, be sure to consult a doctor. This may be a sign of cancer or severe inflammatory bowel disease.

Discuss with your doctor periodic screening for colon cancer. American guidelines recommend regular screening for people after 50 years, as well as for all those who have a genetic predisposition (regardless of age).

Diagnosis of colon cancer.

If the patient's complaints permit the colon cancer to be suspected, the doctor may prescribe the following tests and procedures:.

• Blood tests. There are no specific tests that detect colon cancer, but the results of the tests will help the doctor exclude other causes of problems with the intestine.

• Colonoscopy. This study of the intestine, which is carried out using a long, flexible tube (a colonoscope) with a built-in video camera and backlight. The doctor enters this tube through the anal opening and moves it along the gut, examining the intestinal surface. The same device allows you to conduct a biopsy, that is, take a tissue sample.

• X-ray examination. For x-ray examination, a barium solution is injected into the intestines of the patient. Barium envelops the surface of the intestine, making it clearly visible on X-rays.

• CT scan. This is a rather complex method called virtual colonoscopy. If the patient refuses the usual colonoscopy, then he makes multiple pictures with a tomograph, which then creates a detailed image of the entire intestine.

After confirming the diagnosis, the most important task is to determine the stage of cancer. On this depends the approach to treatment and the fate of the patient. The doctor can prescribe x-rays and CT to determine the size of the tumor and find possible metastases in other organs.

Stages of cancer of the large intestine can be as follows:.

• Stage I. At this stage, the cancer is confined to the mucosa of the large intestine or rectum.

• Stage II. In the second stage, the cancer sprouts through the wall of the large intestine or rectum, but does not spread to neighboring lymph nodes.

• Stage III. The tumor spread to nearby lymph nodes, but has not yet struck other organs.

• Stage IV. In the last, fourth stage, cancer metastasizes to distant parts of the body, into the lungs, the liver or other organs.

Treatment of colon cancer.

The choice of treatment depends on many factors, including the location of the tumor, the stage of the disease, the state of health and personal wishes of the patient himself.

Surgical treatment of colon cancer.

Cancer treatment at an early stage.

If the cancer is detected very early, still localized in the polyp, then the doctor can completely remove it right during the colonoscopy. If a laboratory study reveals that the cancer did not manage to reach the base of the removed polyp, then the chance of recurrence of the disease is minimal.

Some large polyps need to be removed laparoscopically. In laparoscopic surgery, the surgeon makes several small incisions on the abdomen, inserts special instruments and a camera. The whole operation is performed by the doctor, observing his actions through the monitor. During this operation, a nearby biopsy of adjacent lymph nodes.

Treatment of invasive colon cancer.

If the cancer has sprouted through the wall of the intestine, then the doctor will advise removal of the site of the large intestine, along with the tumor and surrounding healthy tissues. The nearby lymph nodes are checked for cancer and, if necessary, also removed.

The surgeon will connect the healthy parts of the large intestine or rectum. In some cases, you may need a colostomy. This procedure consists in creating an artificial hole in the abdominal wall, so that through the remainder of the intestine the waste of vital activity. Colostoma may be temporary or permanent. To collect the fecal masses hang a special colostomy bag.

Treatment of cancer at a late stage.

If the colon cancer is started or the patient's health is very poor, the surgeon can only correct bowel obstruction and other problems to alleviate the condition. Such treatment will not relieve cancer, but will help remove symptoms such as pain, constipation and bleeding.

In special cases, when the cancer metastasized only to the liver, and the state of health is good, the doctor can try to remove the tumor from the liver. Before and after surgery, chemotherapy is needed to improve the chances of the patient.

Radiation and chemotherapy of colon cancer.

Both radiation and cytotoxic drugs are widely used to kill cancer cells. These methods are not the main ones in the treatment of tumors of the large intestine and rectum.

Chemotherapy and radiation can complement surgical treatment of the tumor. This is necessary, because after the operation, cancer cells remain in the patient's body. They can multiply and form a new tumor, so they need to be killed. There are many schemes for independent and combined use of radiation and chemotherapy, before and after surgery.

Directional (targeted) drug therapy.

In recent years, new, specific drugs for the treatment of cancer are actively being developed, which act only on malignant cells and do not harm the healthy. Modern targeted drugs selectively disrupt the proliferation of cancer cells. They can help even patients with advanced cancer. Drugs of the new groups include bevacizumab (Avastin), cetuximab (Erbitux) and panitumumab (Vectibix).

Directed drugs can be used alone or in combination with other treatments. These drugs are usually prescribed for patients with advanced stages of colon cancer.

To some patients targeted drugs help, some do not. Researchers are still working on improving these drugs.

Screening for colon cancer.

People without a genetic predisposition should regularly undergo screening for colon cancer, starting at the age of 50. But if in your family there were cases of colon cancer, you should start screening much earlier. Natives of Africa and American Indians are at risk, so they are recommended to undergo screening at age 45.

There are several options for screening for colon cancer. Each of them has its pros and cons.

Talk with your doctor to help you choose one of the following options:.

• Annual analysis of feces for traces of blood.

• Flexible sigmoidoscopy every 5 years.

• Traditional colonoscopy every 10 years.

• Virtual colonoscopy (CT colonoscopy) every 5 years.

• Analysis of feces on the DNA of cancer cells (the frequency is not defined).

People with a predisposition to cancer are recommended to take these tests more often.

Prevention of colon cancer.

Simple changes in lifestyle will help you reduce the risk of cancer:.

• Eat a variety of fruits, vegetables, whole grains. These foods contain vitamins, minerals, fiber and natural antioxidants that can play a role in cancer prevention. The use of fiber normalizes the work of the intestine.

• Give up alcohol or use it sparingly. American experts recommend not to exceed the daily rate of 1 drink for women and 2 drinks for men (about 30ml and 60ml in terms of vodka).

• Give up cigarettes. Smoking significantly increases the risk of developing several cancers. Talk to your doctor about treatment for nicotine addiction..

• Exercise several times a week. American experts consider the optimal variant of aerobics (moderate load) for 30 minutes a day, at least 3-4 times a week.

• Maintain a healthy body weight. Do not forget that obesity is associated with a high incidence and mortality from cancer of the colon and rectum. In addition, obesity leads to diabetes mellitus. And this is another possible risk factor. To break this vicious circle, take care of yourself. Talk to your doctor about safe ways to lose weight.

Prevention of colon cancer in the risk group.

Methods of cancer prevention in risk groups are actively studied in the West, but so far there are no reliable, proven methods of prevention.

Below are the main tips that can help people with a hereditary predisposition to colon cancer:.

Acetylsalicylic acid (Aspirin).

There is some evidence that Aspirin, with regular intake reduces the risk of polyps in the large intestine. But large-scale studies of regular intake of low-dose Aspirin did not confirm this. Perhaps this effect is achieved only with long-term administration of large doses of Aspirin. But Aspirin, especially in high doses, causes ulcers and bleeding from the gastrointestinal tract.

Taking other painkillers.

Preparations from the NSAID group (ibuprofen, naproxen) have also been studied as agents for the prevention of colon cancer. Some studies have shown a reduced risk of polyps when using these drugs. But side effects can be gastrointestinal bleeding and ulcer. Some drugs from this group are associated with severe cardiovascular complications.

Taking celecoxib.

Celecoxib (Celebrex) is one of the representatives of modern COX-2 inhibitors that are used as pain medications. Recent studies have shown that celecoxib reduces the risk of polyps, including people prone to this problem. But COX-2 inhibitors can sometimes cause severe side effects, including myocardial infarction. In the US, two drugs from this group (including rofecoxib) have already been banned for use because of this risk.

Surgery for cancer prevention.

In cases of rare hereditary syndromes, such as adenomatous polyposis, the doctor can recommend a complete removal of the large intestine or rectum for the prevention of cancer in the future. The same is true for ulcerative colitis, which increases the risk of cancer.

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