Colon carcinoma

What is a colon carcinoma?

Colon cancer is the result of the uncontrolled growth of altered cells that originate from the colon lining cells. Unlike the benign tumour whose growth is limited to the organ in which they were originated, malignant tumour atypical cells (carcinoma) multiply faster and can affect near organs while growing, and if they reach distant organs through blood and lymphatic vessels, they continue multiplying and form metastasis.

The carcinoma is most often developed from the changes called polyps (little benign tumours) which appear on the colon lining, grow slowly and some of them “change“ after a longer period, that is their structure changes and malignant tumour appears.

All polyp changes do not cause the carcinoma. The risk is variable depending on their size and their histological material, and development of the carcinoma requires a long-term process (5-15 years). During that time, they can be determined using early detection method, and then removed to prevent the development of the carcinoma.

Colon Carcinoma Frequency and the Importance of Early Detection

Today colon carcinoma is number two death cause among malignant diseases in the world as well as in our country.

If the carcinoma appears, treatment success is higher if the disease is detected in an early phase.

In most of the cases, the disease can be prevented using preventive examinations and therapy procedures.

If detected in time, 90% of colon carcinoma is curable.

The purpose of preventive examination is the early detection of pre-cancerous changes and their treatment before the carcinoma develops.

Colon carcinoma appearance risk factors

Colon carcinoma appearance risk is equal for both sex and increases with age.

The disease can appear sooner.

Hereditary colon cancer propensity is present in 15-20% cases.

More than 90% of all carcinoma is detected in people over the age of 50.

Factors that increase the colon carcinoma risk:

  • Age (50 or above),
  • Diseases in the family,
    • Colon polyps,
    • Carcinoma: colon, breast, ovary or uterus,
    • Chronic inflammatory bowel diseases: Crohn’s disease or ulcer colitis,
  • Previous disease treatment:
    • Colon polyps,
    • Carcinoma: breast, ovary or uterus,
    • Chronic inflammatory bowel diseases: Crohn’s disease or ulcer colitis,
  • Smoking,
  • Obesity and lack of physical activity,
  • Diet (exaggerated red meat intake, insufficient amount of vegetables and fruit)
  • Alcohol abuse.

What are colon carcinoma symptoms?

Colon carcinoma often appears without any signs. That is why the preventive examinations while there are no symptoms are of great significance.

Symptoms that lead to the need to consult a physician about the necessity of additional diagnostics are the following:

  • Unexplained change in bowel movements,
  • Chronic constipation or diarrhoea,
  • Blood in the stool,
  • Abdominal pain,
  • Loss of body weight without any known reason,
  • Chronic fatigue or unexplained sensation of weakness.

Symptoms are not specific and they can be present as a consequence of other diseases or disorders.

Colon carcinoma symptoms are long absent and when they appear they don’t have to be specific.

Examination methods:

COLONOSCOPY is the most reliable colon examination method.

Colonoscopy: Colon examination by insertion of a flexible instrument (colonoscope) through the anus. If the physician notices lining changes, a biopsy through the working channel can be performed in order to do a pathohistological analysis, and certain therapy procedures are possible, such as stopping the bleeding or polyp removal.

Colonoscopy is the best and the most reliable colon examination method.

“Virtual colonoscopy“

The examination is performed after an adequate preparation and bowel cleaning like for colonoscopy, but a colonoscope is not inserted in the colon, instead, air is introduced through a plastic tube and after that a computerised tomography (C.T.) or magnetic resonance imaging (M.R.I.) is done.

The examination is not invasive, but requires previous preparation, air insertion during the procedure, and in case of certain anomalies detection, requires further examination, as a rule classic colonoscopy.

Occult bleeding stool examination

There are different types of tests, some of which require previous diet (weight restriction, C vitamin, Aspirin…)

A small stool sample is sent to be analysed in order to determine blood presence.

If the test is positive, it does not point out to the presence of blood in the stool and represents an indication for further examination, most often colonoscopy.

Positive occult bleeding stool sample does not necessarily mean the colon carcinoma presence, and the negative test does not exclude it completely.

RTG Colon Examination (Colonography, Irrigography)

RTG examination is an examination during which, after the previous preparation (colon cleaning like for colonoscopy) barium and air are introduced in the colon through the anus and RTG scan is preformed. If some changes are found, further diagnostic procedures (colonoscopy) are often needed.

In the case of inadequate cleanness, stool presence precludes quality examination.

Treatment:

Colon carcinoma is curable in 90% of the cases, if detected on time.

The basic colon carcinoma therapy is surgical. The type of surgery depends on tumour location and tumour development stadium. In certain cases a chemotherapy (use of cytostatics) and radiotherapy are needed.

If the colonoscopy determines the polyp presence, they can be removed endoscopically in most cases, and after their removal occasional control colonoscopic examinations are necessary in order to determine eventual appearance of new polyps. Rational interval between two control colonoscopies depends on the histological material, localisation and the number of removed polyps.

How to reduce colon carcinoma risk?

The safest way to reduce the risk is opportune detection and removal of colon polyps and treatment of the diseases that lead to the risk increase.

General measures to reduce colon carcinoma risk are:

  • Healthy diet: adequate amount of fruit and vegetables,
  • Physical exercises – minimum 30 minutes three times a week (after consulting your physician  and depending on the physical fitness and the presence of limiting factors,
  • Avoiding smoking and alcohol abuse,
  • Some medications (only after consulting a physician and their benefit-risk assessment of taking medications).

Preventive examinations:

Preventive examination is suggested to people over 50.

Early detection and preventive examinations programme can be applied to people under 50 if there are risk factors.

Colonoscopy is recommended as the most reliable preventive examination method.

In case of negative results, examination should be repeated every 10 years (except in high risk appearance cases, when a smaller time interval between two colonoscopies is recommended).

Optimal time for preventive examinations should be discussed with a physician depending on the presence or absence of symptoms and „risk factors“.

Dr. Sci. Med. Zoran Mrđa