Colorectal cancer

Colorectal cancer is a cancer of the tissues of the large intestine and colon. A common type of colorectal cancer is caused by abnormal growth of the epithelial lining of the intestine that becomes a small lump, called a polyp. Over time some of these polyps may turn into cancer. The resection of polyps can prevent them from becoming cancer. Untreated colorectal cancer can spread through the intestinal wall or metastasize to the liver, lungs, brain or bone.

Colorectal cancer is a common type of cancer and is the 3rd leading cause of death in all cancer patients in Thailand.

Colorectal cancer stages

Stage 0 Early phase of cancer. The cancer is only in the inner lining of the colon.
Stage 1 The cancer is only in the inner lining of the colon. It has not spread out of the colon.
Stage 2 The cancer has spread out of the colon, but it has not spread into lymph nodes.
Stage 3 The cancer has spread out into adjacent lymph nodes, but it has not spread to other organs.
Stage 4 The cancer has spread to other organs, usually the liver and lungs.


Risk factors of colorectal cancer

The actual causes of colorectal cancer are not exactly known. However, studies have found that the following factors will increase the chance of developing colorectal cancer.

  1. Age Older people have a greater chance of getting colorectal cancer than young people. The disease is most commonly found in people over the age of 50.
  2. Food Colorectal cancer is associated with a diet high in fat and calories, but low in fiber.
  3. Polyps Some kinds of polyps are normal, but some types may increase the risk of cancer. Some types are transmitted genetically. A common type is called Familial Adenomatous Polyposis in which multiple family members have polyps in the epithelial lining of the large intestine and colon. Most people with this type of polyp are likely to develop colorectal cancer.
  4. Past History Research has found that women with a past medical history of ovarian cancer, cervical cancer, or breast cancer have a high risk of colorectal cancer. Even though a patient has already had colorectal cancer and received completed treatments, the disease can relapse.
  5. Family Health History If one or more family members have a history of colorectal cancer before age 60, family members have a high risk of getting this disease.
  6. Ulcerative Colitis People with chronic inflammation of the inner walls of the large intestine are more likely to develop colorectal cancer than other people.
  7. Smoking Data from studies found that smoking is a key factor contributing to the risk of colorectal cancer and it also increases the mortality rate.

Risk reduction of colorectal cancer

  1. Get screened to detect tumors early and to reduce and to prevent cancer development.
  2. Stop smoking and reduce alcohol consumption.
  3. Exercise regularly.
  4. Consume a high fiber diet regularly such as vegetables and fruits.
  5. Take some medicines and supplements, such as aspirin, folic acid, or vitamin C.
  6. Maintain body weight as per standard Body weight should not exceed the standard (BMI<25 kg/m2) or the waistline should be less than 90 cm in men and less than 80 cm in women.

Symptoms indicating colorectal cancer

  1. Changes in the bowel habits of an individual, mostly occurring as increased frequency, incomplete bowel emptying, and urgently needing to have a bowel movement.
  2. Diarrhea alternating with constipation.
  3. Fresh or dark red bloody stool.
  4. Changes in stool characteristics, i.e. stool lumps changed to thin and flat form.
  5. Stomach bloating, abdominal pain, abdominal discomfort, colic pain, gas in bowel.
  6. Unexplained weight loss.
  7. Weakness, fatigue, inability to do usual activities.

These symptoms may come from colorectal cancer or other diseases. Whenever these symptoms appear, see your doctor immediately to further examine the cause of the symptoms.

Screening of colorectal cancer

People who have a risk of developing colorectal cancer should see a doctor to investigate cancer early, even if no abnormal symptoms have appeared. Doctors and the health care team will explain about tests, appropriate times for screening and diagnosis, as well as monitoring frequency.

In general, screening tests should begin at age 50 including:

– Fecal Occult Blood Test annually
– Colonoscopy every 5 to 10 years
– Flexible sigmoidoscopy along with double contrast barium enema every 5 years
– Computed tomography colonoscopy every 5 years; this test must be performed with a high resolution device

Treatment methods

Treatment of colorectal cancer depends on

  1. Stage of colorectal cancer. How they expand or metastasize.
  2. Whether such cancer causes occlusion or lesion in the large intestine.
  3. Size, position, and type of cancer cells.
  4. Patient’s health (both physical and mental).

General treatment options are as follows:

  1. Surgery
  • Usually preferred to be used in the early stage of colorectal cancer with no metastasis.
  • In case of metastasis of colorectal cancer, surgery will be used when the development of cancer cells causes bowel occlusion in order to relieve symptoms.
  1. Radiotherapy
  • Preferred for use in the treatment of rectal cancer.
  • Can be used along with surgery to eradicate residual cancer cells.
  • Sometimes used to reduce the size of tumors prior to finding other treatments.
  1. Chemotherapy
  • Chemotherapy is typically used along with other methods, such as surgery, to eradicate residual cancer cells from the surgery or undetectable small cancer cells.
  • When colorectal cancer has metastasized to other parts of body, there is a very small chance to cure the disease. Chemotherapy is often used to stop cancer metastasis and to relieve symptoms or suffering from cancer, in order to provide the best quality of life and to the increase patient’s survival rate. This is called palliative treatment.
  1. Targeted therapy
  • A treatment specifically targeting cancer cells, such as anti-angiogenesis therapy in cancer cells, etc. A drug or a substance is given to inhibit cell signaling which is the cause of cancer cell growth and proliferation.