Colon polyps and the pathogenesis of colon cancer – colorectal carcinoma

The colon polyps develop sporadically, the proportion of benign to malignant forms depends on the histological type and the size of the polyp (increasing risk). Today we also know that especially flat polyps in the area of the right half of the colon carry a high risk to become malignant. The pathogenesis of colon cancer can differentiate strongly. High risk factors are an increased consumption of animal fat and a fibre-poor nutrition. The risk is increasing in proportion to the growing age and especially important is the family hereditary and a family disposition to develop polyps and cancer.

Only the so-called double balloon enteroscopy (DBE), also known as "push-pull enteroscopy" or the "double-bubble", is a new endoscopic technique that allows pan-enteric (complete) allows the examination of the small bowel up to the T-junction of the small intestine. In the course of this examination the polyps are ablated completely with an electrical sling. In addition, a thorough documentation of screen shots and localisation of the polyps is made. The patient is informed about the respective risks of the ablation (bleedings, perforation of the colon) in the course of a pre-operation discussion. It is the only way to prevent colon cancer that develops from polyps in time. Due to our recommendations the first enteroscopy should be made at the age of 50. The intervals of the following examinations are depending on the founding and the histological results of the polyps. Significantly rarer are carcinomas that are developing from unsuspicious mucosa. By this form of carcinoma patients can only be prevented from by healthy and vitamin-rich nutrition.

Smaller polyps show no symptoms at all, larger polyps sometimes cause obstructions or bloody stools. When suffering from carcinoma there is a change in stool habits with a change from obstruction to diarrhoea, in addition, loss of blood and signs of anaemia in form of iron deficiency shows up. Alarming symptoms are weight loss or total constipation of stool.

The making of a diagnosis is pain-free for the patient and made by an enteroscopy that is done after the patient was given a laxative and a mild soporific. If cancer has already been diagnosed a tissue sample is extracted to specify the histological type of cancer and its pace of growth. When doing this the exact localization of the colon cancer is decisive for finding the right therapeutic treatment. The sheer magnitude of the cancer can only be told after an operation has been made where the infiltration of the cancer into the tissue and lymph nodes can be diagnosed. It is also necessary to closely examine other organs of the patient like liver and lung as well as the lymph nodes situated in the abdominal region. Also helpful is the tumor marker (CEA = Carcinoembryonic antigen (CEA) is a protein found in many types of cells but associated with tumors) that should be examined regularly in the course of the patient’s after-care.

Polyps can either be removed endoscopically or in the case of an extreme enhancement by means of an operation. The colon cancer, as soon as the cancer only spread to the upper hindgut, can be removed easily by an operation whereas also the lymph nodes can be removed. Depending on the growth rate and the infiltration of the tumor into the lymph nodes it is decided if adjuvant preventive chemotherapy has to be done. The chemotherapy today is normally accommodating well by the patients.

When the cancer has already infiltrated the hindgut maybe a chemo- and radiation therapy have to be made in advance to the operation in order to obtain the function of the sphincter and still be able to operate with a sufficient safety gap. It is more advantageous to have this combination therapy before having the operation. If the cancer is located too close to the sphincter of the anus, in addition, an artificial anus must be formed in order to achieve a safety gap to prevent from a cancer spreading. At an early stage of the cancer there is also the possibility to scrape out the carcinoma of the hindgut. When doing this it must be sure that the tumor is only spread to the mucosa and this diagnosis must be validated by means of a rectal ultrasound.