Colon cancer (colorectal carcinoma)

Description

Colon and rectal carcinomas are malignant growths of the mucous membrane in the respective section of the intestine. Experts also refer to these cancers as colorectal carcinoma, derived from the Greek "colon" (intestine) and Latin "interstitium rectum" (rectum). The term colon carcinoma actually refers only to cancer of the colon, but is often used to refer to cancer of the large intestine and rectum.

Cancers of the colon are the second most common in industrialized countries. Only prostate cancer (in men) and breast cancer (in women) are more common.

Colorectal cancers usually occur after the age of 50; on average, women develop the disease slightly later than men. More than two-thirds of malignant growths develop in the last section of the colon or rectum. The mortality rate is slowly but steadily decreasing.

Certain risk factors have been shown to favour the development of colorectal carcinomas:

• Adenomas (intestinal polyps - mucosal protrusions) precede 90 % of carcinomas.
• Inflammatory bowel diseases (e.g. ulcerative colitis, Crohn's disease)
• previous colorectal carcinomas
• Lack of exercise
• Overweight
• Alcohol and nicotine consumption
• frequent consumption of meat products and animal fats
• low-fibre diet (little fruit, vegetables, wholemeal products)
• familial accumulation of intestinal polyps and cancer

Colorectal carcinomas usually cause only non-specific symptoms:

• Changes in the type and frequency of bowel movements (long-lasting and changeable constipation or diarrhoea) without external causes such as living conditions.
• (In-)visible blood in the stool (detectable with chemical tests such as occult blood test, hemoccult test)
• Fatigue, loss of appetite, unwanted weight loss, anemia (anemia)
• Pain (e.g. due to large growths that severely constrict the intestine)

These warning signs should be clarified by a doctor, especially if you belong to a risk group (e.g. older than 40 years).

Screenings

Everyone over the age of 50 should have regular colorectal cancer screening.

At ages 50-54, individuals are eligible for a test to detect blood in the stool (occult blood test, hemoccult test).

After age 55, a colonoscopy (colonoscopy) can be performed if desired. This examination should be repeated every 10 years if the results are negative. For those who refuse a colonoscopy, there is the option of a haemoccult test every 2 years at health insurance cost.

Cancer stage

During the physical examination, the attending physician thoroughly palpates the rectum. If there is a suspicion of colon cancer, a colonoscopy provides the clearest results. In addition, the entire colon should always be examined, since tumors can form in different places.

Biopsies (tissue samples) are taken from abnormal areas, which on further examination will give results as to whether cancer is present or not. Other methods, such as X-rays, may provide clues but not proof.

If cancer is diagnosed, it is important for treatment to know how deep the growths go into the bowel wall. This can be determined by endosonography (ultrasound examination from the inside).

CT (computer tomography) and MRT (magnetic resonance imaging) provide information about the size of the tumor, as well as any metastases (daughter tumors). The lungs (X-ray) and the abdominal cavity (especially the liver, ultrasound or CT) are also examined.

If there is a suspicion that the growth is also affecting the urinary bladder, a cystoscopy is performed. A skeletal scintigraphy can be used to determine whether the cancer has also spread to the bones.

In the case of colon cancer, a special protein (CEA - carcinoembryonic antigen) can be detected in the blood. Although this tumour marker is not sufficient for a diagnosis, it is decisive for the prognosis.

In exceptional cases, genetic counselling with examination of the genetic material can also be carried out in order to inform relatives about their risk of contracting the disease.

The treatment of colorectal cancer depends on factors such as the size, location, and spread (to other organs) of the tumor.

Surgery

If diagnosed early, degenerated polyps can be removed during a colonoscopy.

Later, extensive removal of intestinal tissue is the most common treatment. Lymph nodes and also healthy tissue around the tumor have to be removed in order to remove not yet visible extensions and to exclude spreading via the lymphatic system.

Due to the length of the colon, the operation does not lead to significant restrictions in the life of the affected person. In some cases, however, a stoma (artificial bowel outlet) has to be inserted in the short or long term.

Chemotherapy and radiotherapy

Chemotherapy is usually given in addition to surgery if tumor cells have also been detected in the lymph nodes. In cases of cancer in the lower two-thirds of the rectum, combinations of chemotherapy and radiotherapy have shown good results.

Antibodies

In advanced disease, immunotherapy with antibodies is also approved (cetuximab). These antibodies are intended to prevent the growth impulses from penetrating into the interior of the cancer cells.

Other antibodies (Bevacizumab) inhibit the formation of new blood vessels that the tumour needs to supply with nutrients. Pantitumumab is another antibody used when standard chemotherapy is unsuccessful.

Currently, interferons and -leukins (immune system signaling substances) are being tested for their effectiveness in clinical trials.

Pain management

Concomitant symptoms such as pain can be treated with medication as part of palliative therapy.

Other therapies

If the carcinoma cannot be completely removed, hyperthermia (hyperthermia), cryotherapy (cold) and laser irradiation are also options. However, these procedures are mostly used to target metastases.

The prognosis for colorectal carcinoma depends mainly on how advanced the tumor is. With early detection and complete removal, the chances of cure are up to 90%.

However, the 5-year survival rate is only 60%.

The more the disease progresses, the lower the chances of cure.

Possible complications:

• Metastases (daughter tumors) in the liver, lungs, skeleton
• heavy blood loss
• intestinal obstruction

Colorectal cancer is predominantly found in western industrialized countries. Dietary and lifestyle habits have a strong influence on the likelihood of developing the disease.

A healthy lifestyle and a varied, balanced diet have a preventive effect. Fibre, sufficient vegetables and fruit are particularly advisable. Red and unprocessed meat should not be on the daily menu.

Preventive examinations are advisable from a certain age. Just ask your doctor about this at the next opportunity.

• In the 50th - 54th year of life you are entitled to a test to detect blood in the stool (occult blood test, haemoccult test).
• From the age of 55 you are entitled to a colonoscopy (examination of the large intestine), which should be repeated every 10 years if the result is negative.
• Those who refuse this examination can have a haemoccult test carried out every 2 years instead.
• A computed tomography scan can be used to detect polyps. However, specialists do not recommend it as an alternative to colonoscopy.
• If you find blood in your stool, or if the frequency and type change spontaneously, consult your doctor for clarification.
• Those who have an increased risk of disease can make use of individual screening plans.