Colorectal cancer

What is colorectal cancer?

Colorectal cancer develops from cells in the mucous membrane of the colon or rectum. The large intestine moves digested food masses towards the rectum, after which they are excreted from the body.

Most often, colorectal cancer develops from certain types of polyps or growths in the colon. Screening tests can detect precancerous polyps before they develop into malignant tumors. Colorectal cancer without timely treatment can spread to other parts of the body. Thanks to screening tests, early treatment and new therapies, fewer people are dying from colorectal cancer.

How does colorectal cancer affect people?

The colon wall is made up of three layers - mucous, muscle and serous. Colorectal cancer develops in the mucosa, which is the inner lining of the colon, which is made up of cells that produce and secrete mucus and other fluids. A colon polyp forms as a result of a mutation or change in such cells. Over time, colon polyps can become cancerous (it usually takes about 10 years for a colon polyp to develop into cancer). If cancer is not detected and treated early, it will spread to other layers of the colon and continue to grow. Colorectal cancer can also spread to other areas of the body through lymphatic channels or blood vessels in those areas.

Who gets colorectal cancer?

Colorectal cancer usually affects people over the age of 50. However, over the past 15 years, the number of colorectal cancer cases among people aged 20 to 49 has increased by about 1.5 per cent each year.

Symptoms and causes

Six of the most common symptoms  of colorectal cancer

Symptoms of colorectal cancer

Generally, the early stages of colorectal cancer are not characterized by pronounced symptoms, it can be asymptomatic. However, the presence of symptoms and changes in the body does not necessarily indicate the presence of cancer, as some symptoms of colorectal cancer are similar to those of less serious diseases. Common symptoms of colorectal cancer include:

Bloody defecation: Consult your doctor if you notice traces of blood in the stool or on the surface of the anus, and if the stool is dark or bright red. It is important to remember that bloody stools do not necessarily mean you have colorectal cancer. A change in stool color can be caused by a variety of reasons, such as hemorrhoids, anal fissures, and the intake of various foods and medications. However, you should consult a doctor if you notice any suspicious symptoms.

Constant changes in defecation: consult a doctor if you suffer from constant constipation and alternating diarrhea, as if the bowel cannot empty, or from a feeling of unsatisfied defecation.

Abdominal pain: Consult your doctor if you have unexplained or persistent abdominal pain. Abdominal pain can be caused by many things, but it is best to consult a doctor if you have unusual or frequent abdominal pain.

Abdominal bloating: Like abdominal pain, bloating can be caused by a variety of reasons. Consult your doctor if your abdominal bloating lasts longer than a week or gets worse, and if you experience symptoms such as vomiting and bloody stools.

Weight loss without cause: noticeable weight loss when you are not trying to lose weight.

Nausea: Consult your doctor if you have recurrent nausea for no reason or if you vomit several times in 24 hours.

Feeling tired and shortness of breath: These are symptoms of anemia. Anemia can be caused by colorectal cancer.

Like all cancers, colorectal cancer is caused by uncontrolled disorderly growth of abnormal cells. All cells in the human body are constantly growing, dividing, and dying. This is how the body maintains health and functions properly. In colorectal cancer, cells in the mucosa of the colon and rectum continue to grow and divide even when they should be dying. Cancer cells can develop from colon polyps. Scientists have not identified the exact reason why some people develop precancerous colon polyps that later turn into colon cancer. The specific risk factors that lead to precancerous polyps and colorectal cancer in people remain unknown.

Risk factors include certain diseases, including hereditary diseases, and lifestyle. However, the presence of one or more risk factors for colorectal cancer does not mean that the disease will necessarily develop. It only indicates that a person is at increased risk. If you know your risk factors, you only need to contact your doctor and tell him or her that you are at risk of developing colorectal cancer.

Lifestyles that increase the risk of developing colorectal cancer

• Tobacco use: Use of tobacco products, including chewing tobacco or e-cigarettes, increases the risk of colorectal cancer.
• Excessive alcohol use: You should reduce the frequency of alcoholic beverages. Even infrequent alcohol consumption can increase the risk of developing cancer.
• Overweight: Consumption of fatty and high-calorie foods can affect body weight and increase the risk of developing colorectal cancer.
• Diet high in red and processed meats: Processed meat products include bacon, sausage and frankfurters. Experts recommend limiting your intake of red and processed meats to two servings per week.
  • Lack of physical activity: Any type of physical activity can reduce the risk of developing colorectal cancer.

Diseases that increase the risk of developing colorectal cancer

• Inflammatory bowel disease: People with chronic ulcerative colitis and Crohn's disease, which cause inflammation of the mucous membrane of the colon, may be at increased risk of developing colorectal cancer. The risk also increases with inflammatory bowel disease if it lasts more than seven years and spreads to large areas of the colon.
• Hereditary diseases: Certain conditions, such as Lynch syndrome and familial adenomatous polyposis, increase the risk of developing colorectal cancer. Colorectal cancer can occur when a cancer-causing gene is inherited.
• Family history of colorectal cancer and other cancers: If any close relatives have colorectal cancer, you may have an increased risk of developing the disease. Close relatives include biological parents, siblings, and children. The risk is higher if a biological family member developed colorectal cancer before the age of 45.
• Family history of polyps: If any of your parents, siblings or children have been diagnosed with late-stage polyps, you may be at an increased risk of developing colorectal cancer. A late-stage polyp can be a large polyp. According to pathologists, a polyp is at a late stage when microscopic examination reveals certain changes in the polyp that indicate that the polyp may contain cancer cells.
• Multiple polyps: People with multiple colorectal polyps - adenomas, serrated polyps or other types of polyps - are often at increased risk of developing polyps and colorectal cancer.

Management and treatment of the disease

Treatment of colorectal cancer

Treatment for colorectal cancer is complex, but the most proven method in the early stages is surgery. There are various methods and procedures for the surgical treatment of colorectal cancer:

• Polypectomy: During this surgery, polyps are excised endoscopically, but there are cases when they cannot be removed endoscopically and the patient requires excision of a segment of the colon laparoscopically.
• Partial colectomy: the same as resection of the affected area of the colon. Surgeons cut out the part of the colon affected by the tumor, along with a small amount of adjacent healthy tissue and regional lymph nodes and collectors, and then reconnect the healthy parts of the colon. This procedure is called an anastomosis.
• Surgical resection with colostomy: As with a partial colectomy, surgeons excise the part of the colon where the tumor has formed. However, during this surgery, the healthy parts of the colon are not connected  together, but a colostomy is done. During a colostomy, the colon is moved to  the front wall of the abdominal cavity, and in this way the faces are collected in a bag.
• Radiofrequency ablation: In this procedure, heat energy is used to kill cancer cells .

Doctors may combine surgery with neoadjuvant therapy, which involves treating the cancer before or after surgery. This form of therapy is used during the spread and recurrence of colorectal cancer. Treatment methods include:

• Chemotherapy: Doctors may use chemotherapy drugs to reduce the size of the tumor and relieve the symptoms of colorectal cancer.
• Targeted therapy: This treatment method targets genes, proteins, and tissues that promote the growth and multiplication of colorectal cancer cells . Specialist doctors often use a form of targeting therapy called monoclonal antibody therapy. This therapy uses lab-created antibodies that attach to specific targets on cancer cells or to cells that promote the multiplication of cancer cells. The antibodies kill the cancer cells.

Prevention

Can colorectal cancer be prevented?

Colorectal cancer cannot be prevented, but you can reduce your risk of developing the disease by controlling the following risk factors:

• Avoid tobacco use;
• Use alcoholic beverages in moderation;
• Maintain a healthy body weight;
• Consume healthy foods. Include more fruit and vegetables in your diet and reduce your intake of processed meats, fatty and high-calorie foods. Coffee helps reduce the risk of developing colorectal cancer;
• Monitor your family history. Colorectal cancer is an inherited disease. Tell your doctor if any of your biological parents, siblings or children had colorectal cancer or polyps, or if a family member had cancer before age 45;

• Follow the colorectal cancer screening guidelines. Ask your doctor when you should be screened for colorectal cancer. If you have irritable bowel syndrome or a family history of colorectal cancer, get screened before age 45 on your doctor's recommendation.