Colorectal cancer: how to prevent it? – Fitness and well-being

Colorectal Cancer (CRC) is a very common type of cancer, with a significant impact on patients’ health. This type of cancer begins with the appearance of polyps, which are changes caused by the abnormal development of tissue in the large intestine that over time grow and transform into cancer. Most polyps are not malignant in the first few years and anyone can develop these lesions.

There are several known factors that alter the risk of developing colorectal cancer, and all the causes of this disease are not yet known. There are risk factors that cannot be modified, such as age (especially over 50 years old), genetic syndromes or family history of cancer. However, other important risk factors are known and can change. Avoiding tobacco, moderating alcohol consumption, staying physically active, adopting a diet rich in fiber and low in red and processed meat are measures that can reduce this risk.

Carrying out screening tests (i.e., in people without symptoms) is important to prevent and detect this type of cancer early, and it is recommended to start from the age of 50. There are several methods for screening for CRC: fecal occult blood testing (PSOF), colonoscopy with or without anesthesia, computed tomography (CT) colonography, also known as “virtual colonoscopy”, colon capsule and stool DNA screening. (the latter used mainly in research). The most recommended methods are fecal occult blood testing and colonoscopy. The PSOF is simpler to perform, using a stool sample collected at home and delivered to the laboratory. It is a non-invasive method and allows the detection of many cases of CRC (sensitivity of 80%), being less effective in detecting polyps. After a positive PSOF, there is an indication for a colonoscopy that will allow identifying (or excluding) any changes.

Colonoscopy is the most effective method for identifying polyps and cancer cases (sensitivity greater than 85%). Colonoscopy allows direct observation of a problem, but also the removal of polyps and the collection of small fragments of tissue for analysis (biopsies). Despite being the most effective method, it can have some complications and is considered an invasive method. CT or colon capsule colonography are less commonly used as a first screening test and are less accessible. They are usually used in cases of incomplete colonoscopy or due to the patient’s preference for a less invasive examination. Both also require intestinal preparation and, if any changes are identified, it will be necessary to subsequently carry out a colonoscopy to remove lesions or clarify any doubts.

Screening can allow the detection and removal of polyps before they become malignant, in addition to diagnosing cases of cancer early, increasing the chances of successful treatment. There are specific contexts in which earlier screening may be recommended. For example, if you have a family history of CRC and/or more advanced polyps, the starting age for screening could be 40 years old or 10 years earlier than the youngest case in the family. There are other even more specific cases, such as patients with inflammatory bowel disease, genetic diseases, among others, in which patients must be advised by the specialist accompanying them. Soon, the starting age may be brought forward to 45 years.

The presence of colorectal cancer can often cause very mild symptoms or even no symptoms at an early stage, which highlights the importance of screening (i.e., having an exam without having any complaints). Symptoms of Colorectal Cancer may be mild, but blood loss in stool, unintentional weight loss, abdominal pain and persistent changes in bowel habits should be evaluated and investigated by a doctor.

In conclusion, preventing Colorectal Cancer involves a combination of lifestyle changes and screening at the appropriate time for each patient. With prevention and early detection it is possible to significantly reduce the impact of this disease.

An opinion article by Eugénia Cancela, gastroenterologist and Member of the Portuguese Society of Digestive Endoscopy (SPED).