What is colon cancer? Symptoms, diagnosis and treatments

¿Cuánto sabemos sobre el cáncer de colon?

What is colon cancer?

The colon or large intestine is the portion of the digestive tract located between the small intestine and the rectum and consists of four parts, ascending, descending, transverse, and sigmoid. Its function is basically to absorb water and salts from digested food in the upper reaches of the digestive tract. The rectum is the final section of the digestive tract and its function is to form and store stool.

Cancer of the large intestine is the most common cancer of the digestive system. Colon cancer almost always develops from a benign lesion called a polyp, which over the years can develop into a malignant tumor. Sometimes it also affects the rectal area, (end of the colon) and is called colorectal cancer. Only 5-10% of such polyps become cancer.

This type of cancer is one of the most common. And its incidence has increased in recent years. Colon cancer is currently the third most common in men and the second in women. However, it is a tumor that is easy to diagnose and when it is detected at an early stage, cure rates are very high.


Colon cancer symptoms

The symptoms of colon cancer may vary depending on the location of the tumor in the large intestine.  However, the most frequent discomforts are usually:

  • Blood in the stool: the color of the blood can be red or black. Red appears when the person presents tumors of the most distant part of the colon and rectum. Black blood appears because it is digested and comes from sections of the colon closest to the small intestine.
  • Changes in the intestinal rhythm: the patient suffers from periods of constipation combined with periods of diarrhea.
  • Abdominal pain or discomfort: The tumor partially obstructs the intestinal tube and pain similar to that of colic occurs.
  • Weight loss without apparent cause and appearance of tiredness.

What are the causes of colon cancer?

The main causes of colon cancer are:

Environmental factors:

  • Consumption of alcohol and tobacco.
  • Obesity and high caloric intake.
  • Diet rich in fats and poor in fruits, vegetables and fiber.

Genetic factors:

This cancer may appear from a family history. Although family membersa may have presented other types of cancer such as breast or pancreas or have suffered from diseases that predispose to the appearance of polyps in the colon.

Age can also be a risk factor, since the probability of the appearance of this disease can increase from the age of 40. However, it can also develop at earlier ages.

6 tips for the prevention of colon cancer

There is no absolute way to prevent colon cancer, but it is possible to take certain measures that can help reduce your risk:

  1. Avoid constipation
  2. Reduce alcohol consumption and avoid tobacco.
  3. With age, get regular checkups.
  4. Pay attention to your bowel movements.
  5. Get regular physical exercise.
  6. Intake of a diet rich in fiber, fruits and vegetables.

How is colon cancer diagnosed?

When colon cancer is dignosed when it still has no symptoms, you are more likely to outgrow this type of tumor, which has high cure rates.

According to the AECC, survival to this disease, after 5 years of being detected early, stands at 64% of patients, a figure higher than the average for European countries, which is 57%.

The diagnosis is based on the combination of a series of tests:

  • Stool occult blood test: it is used to find out if there is blood that is not visible to the naked eye.
  • Physical examination: a rectal examination is performed to rule out the presence of physical abnormalities, lumps, or pain in the rectum.
  • Barium enema with double contrast: it is a type of x-ray, focused on the colon and rectum.
  • Colonoscopy: it is used to observe the inside of the digestive tract through a tube that is inserted through the rectum and to take samples of the tissue or suspicious lesions (biopsy) and then analyze them

What treatments are applied to colon cancer?


The goal of this treatment is to eliminate all cancerous tissue by surgery. Depending on the degree of evolution, this operation will have a curative purpose or may require additional treatments and even, in advanced cases, it will only constitute a palliative treatment. Hence, early identification is especially relevant.

Chemotherapy / Radiotherapy

In cases where surgery cannot ensure complete removal of cancerous tissue, metastases, or there are risk factors that may indicate that the tumor will recur, treatment may include chemotherapy and / or radiation therapy.

Chemotherapy may be given as an additional treatment after or before surgery, or instead of surgery if cancer cells have spread to the liver or other places in the body. It can also be personalized depending on the genetics of the tumor. Another option is to integrate the two treatments at the same time, performing cytoreductive surgery (where the tumor and implants that may have been produced inside the abdomen are removed) and HIPEC, which consists of applying a dose of hot chemotherapy directly to the tumor during the surgery itself.

Radiation therapy is not routinely used in colon cancer but in rectal cancer both to decrease the initial size of the tumor as well as after surgery

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