Colorectal cancer: Risk factors and the importance of screening

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Increasingly, this type of malignant neoplasm has been diagnosed in women and men under 50 years of age.

Recently, colorectal cancer has started to gain more media attention. First, with the announcement of the death of Pelé, who died at the end of December 2022 from this type of cancer. Later, when the singer Preta Gil announced that she received the same diagnosis, in January 2023.

Colon malignant neoplasm, which is also called colorectal cancer, colon cancer, large intestine cancer or simply bowel cancer, is one of the tumors that affects the digestive system and reaches the colon, the final portion of the large intestine, the rectum and the anus. The National Cancer Institute (INCA) estimates 44,000 new cases per year of this type of malignant neoplasm – 70% of them concentrated in the Southeast and South regions of the country.According to a study published in the journal Nature Reviews: Clinical Oncology, from Harvard University, since 1990 there has been a significant increase in cancer diagnoses in people under 50 years of age. Colorectal cancer is part of this list alongside malignant neoplasms of the breast, esophagus, pancreas and ten other types of cancer.

Causes and risk factors for developing colorectal cancer

  • Unbalanced diet: scientific evidence links this type of cancer to a high-fat, high-calorie, low-fiber diet, with an excess of red and/or processed meat. Alcohol consumption also enters the account;
  • Smoking and obesity: both are related to the appearance of the disease. Therefore, quitting smoking and combining a healthy diet with regular physical exercise is more than recommended by doctors;
  • Intestinal constipation: prolonged contact of feces with the walls of the colon and rectum increases the risk of developing the disease;
  • Presence of polyps: from the age of 50, small clusters of cells can form that have lost control of their ability to duplicate and settle on the wall of the intestine. Most polyps are benign, but they must be removed, as many tumors originate from some types of polyps;
  • Family history: About 30% of people diagnosed with colorectal cancer have a history of the disease among relatives. Likewise, those who have hereditary diseases such as Lynch syndrome, familial adenomatous polyposis and MUTYH polyposis, to name three examples, should have regular follow-up with a doctor;
  • Inflammatory bowel diseases: people with Crohn’s disease and ulcerative colitis should undergo medical follow-up, as they are at increased risk of developing malignant colon cancer.

Blood in the stool and other symptoms of colorectal cancer

As with other malignant neoplasms, early diagnosis increases the possibilities of treatment and cure. Therefore, the importance of observing changes related to the intestine. In the case of colorectal cancer, the main symptom is the presence of blood in the stool. But there are other signs that vary according to the location of the tumor:

  • Anemia, weight loss and, when the disease is advanced, the presence of a palpable mass in the belly are the most common symptoms when the tumor is located on the right side of the abdomen;
  • If the tumor is on the left side of the abdomen or in the rectum, close to the anus, the main signs are changes in bowel habits and rectal bleeding.

The importance of colorectal cancer screening

Colonoscopy is the most important test for detecting tumors and checking the health of the colon and rectum. Before, the indication was to have the first colonoscopy from the age of 50; currently, it is recommended that it be included in the routine examinations of people over 40 years of age. For those who have cases of this type of cancer in the family, the recommendation is to start screening about ten years before the age that the relative in question was when he received the diagnosis. As for the frequency of colonoscopy, the recommendation of the Brazilian Society of Coloproctology (SBCP) for low-risk patients is to repeat the exam every five years. For those who have a history of the disease in the family, the periodicity is usually lower. The doctor makes the recommendation according to each case.

Polyps in the intestine can be the beginning of everything: evolution to a tumor

Polyps are clusters of cells that have lost control of their ability to replicate and become attached to the intestinal wall. Most of them are harmless, but there are certain types that are premalignant and can develop into a tumor.

Generally, the doctor removes all of them during the colonoscopy and, depending on the case, indicates a new colonoscopy some time later for verification. In case of diagnosis of cancer, surgery and sessions of chemotherapy and radiotherapy may be necessary to contain the progression of the disease and avoid metastasis, which appears in up to 20% of cases.

check out the series Understanding Cancer to read all the texts we produce about the most common forms of the disease, learn about the subject and know what is true or false when talking about this very important subject.


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