Colon Cancer: A Detailed Look at Causes, Prevention, and Treatment

Colon cancer is the second most common cancer among women (after breast cancer) and the third among men (after lung and prostate cancer). Also the one with the highest mortality, even ahead of lung cancer. However, paradoxically, colon cancer is one of the most treatable. An early diagnosis greatly increases the chances of a cure. If detected early, it can be cured in 90% of cases.

What is colon cancer?

Colon cancer usually starts in polyps or "bumps" that appear in the innermost layer of the large intestine, the mucosa. These polyps are initially benign, take between 10 and 15 years to grow and only 5-10% become malignant. However, it is convenient to detect as soon as possible and remove all types of polyp to avoid your potential risk of becoming cancer.

Colon cancer affects women and men indistinctly, although there are especially sensitive population groups who are more likely to have the disease:

• With age, the risk of colon polyps increases. It usually appears from the age of 50; it is unusual for it to affect those under 40 years of age.
• People with a personal and family history of colon cancer and / or polyps. If a close relative (grandparents, parents, siblings ...) has suffered from the disease, it is possible that it has been transmitted by genetic means. Likewise, if the appearance of polyps or cancer has already occurred in the person, the risk of a new tumor increases.
• People with inflammatory bowel diseases, such as ulcerative colitis or Crohn's disease.

Others risk factor's that predispose the appearance of cancer, not only the appearance of polyps, and that must be taken into account are:

• Poor diet is often associated with diets rich in animal fats (red meat) and poor in fiber.
• Physical inactivity, since leading a sedentary life and not doing any physical activity also increases the risk.
• Consumption of tobacco and / or alcohol; both facilitate the development of polyps in the colon mucosa, which can be the precursors of cancer.

For all these reasons, it is important to lead a healthy lifestyle, play sports, put aside bad habits and follow one.

Colon cancer symptoms

Colon cancer symptoms can vary depending on your location within the large intestine. In the event that any of them appear, you should go to the doctor as soon as possible to carry out the necessary diagnosis and treatment. Many of these symptoms can coincide with those of other less important diseases, such as hemorrhoids, diarrhea or digestive disorders. These symptoms are:

• Blood in the stool: it is one of the most common symptoms of colon cancer. It can be reddish blood or black blood, which mixes with the stool giving rise to black stools called melena (more frequent when the tumor is in the ascending colon). After a certain time of bleeding, and if you do not go to the doctor (or if the blood loss is so little that it is not seen with the naked eye, hidden in the stool), anemia usually appears, which in turn leads to a series of symptoms such as the feeling of shortness of breath, tiredness, palpitations, dizziness ...
• Change in bowel movements: Diarrhea or constipation (and often interspersed with each other) occurs in people with a previous normal bowel rhythm.
• Change in stool: narrower, tapered, usually due to the tumor narrowing the intestine and not allowing the normal passage of stool.
• Tenesmus or sensation of incomplete defecation; it usually appears in tumors located in the rectum or the final section of the colon.
• Abdominal pain: it is common, although it is generally non-specific pain. When the tumor partially closes the intestinal tube, a picture of pain similar to that of colic occurs. When the closure is complete, it is accompanied by constipation, vomiting and a great alteration of the general state. pain caused by perforation of the intestine (wall weakened by the tumor) is also possible.
• Extreme tiredness, weight loss and loss of appetite: these are general and nonspecific symptoms that usually occur in many diseases, including tumors.

Importance of early diagnosis

Colon cancer is one of the few cancers that can be diagnosed early, that is, before the person notices any symptoms. For this, different tests are used and only if the first is positive, or if there are clear indications of a problem, other tests are used to confirm it:

• Fecal occult blood test: it is very simple and painless and it is used to detect if there is blood in the stool. It is done by the patient himself at home. A stool sample is taken for three consecutive days and placed in a special envelope containing several test strips. The reading of the test is carried out by healthcare personnel and consists of placing a few drops on the strips and observing if they vary in color. In this case, the test is positive, that is, there is blood in the stools, and further studies are required to diagnose its origin (hemorrhoids, polyp, malignant tumor ...).
• blood and urine analysis: they are used to know the general condition of the patient and detect complications associated with the tumor process.
• Digital rectal exam: The digital rectal exam consists of digital examination of the anus and part of the rectum. The doctor puts on a glove and uses lubricant to gently slide the finger through the anus and explore the area, palpating the possible changes in the walls of the rectum.
• Colonoscopy: with this test, the mucosa of the entire colon and rectum is observed through a long, flexible tube (endoscope) that is inserted through the anus. At its end it has a light and a camera that allow any alteration of the mucosa to be seen on a television monitor. To perform this test, the person must follow a special diet for two or three days and before the test use laxatives so that the colon and rectum are clean. Currently, colonoscopy is performed under sedation. Thus, the patient does not feel pain, is relaxed, and discomfort caused by distension of the digestive tract when inserting the endoscope is avoided.
• Biopsy: if during the colonoscopy the doctor observes a suspicious lesion, he will proceed to extract a small tissue sample, which must be analyzed to confirm or rule out the existence of cancer.
• Other tests: If colon cancer is finally diagnosed, other tests should be done to find out if the disease has affected other organs or only affects the digestive tract, such as chest X-rays, ultrasound scans, and tumor markers.

Which is the treatment?

The main treatment is usually surgical removal, With excision of the affected area, it may be the polyp alone or the affected section of intestine. The reconstruction will vary depending on the location (direct union of both ends, direct to the anal canal or colostomy to the abdominal wall). In case of extension outside the intestine (to lymph nodes in the area or to other distant organs, metastases), complementary treatments such as radiation therapy or chemotherapy.