Screening, prevention and the treatment of colorectal cancer
Colorectal cancer is cancer of the large intestine, which consists of the colon and rectum. The incidence of this bowel cancer is increasing at alarming rate in Southeast Asia and may become the number one type of cancer over the next 10 to 20 years.
Health education remains the cornerstone in the early detection of this cancer, which can be cured. Looking for symptoms suggestive of colorectal cancer is very important. The symptoms include irregular bowel habits, increasing constipation, persistent diarrhea, presence of blood in the stool, abdominal distension and pain. People with these symptoms should seek medical attention as soon as possible.
There are several tests that a doctor may recommend when patients have any of these symptoms. The most accurate test to detect colorectal cancer is a colonoscopy. A small flexible fiber optic camera is introduced into the large intestine with the patient under heavy sedation. Any abnormality of the intestine can be seen and a biopsy can be taken for any suspicious growth. Less accurate tests, such as CT coronagraphy and Barium enema, are not recommended when patients have symptoms suggestive of colorectal cancer. A biopsy cannot be carried out with these tests when an abnormality is detected. Patients have to be sent for a colonoscopy and biopsy if an abnormality is detected.
Many risk factors have been postulated to increase the risk of colorectal cancer. These risk factors include sedentary lifestyles, fatty food, a low fiber diet, or the consumption of alcohol. None of these risk factors has been proven to directly increase the risk of the developing colorectal cancer. However, small growths in the large intestine, called polyps have been well documented to increase the risk of colorectal cancer. These colorectal polyps will grow in size and gradually transform into colorectal cancer. It has been shown that some polyps will take about three to five years to become cancerous. The prevention of colorectal cancer can be achieved if these polyps are detected early and removed. Thus, the most effective way of fighting colorectal cancer is early detection and destruction of these polyps during the colonoscopy.
Who should be screened for presence of colorectal cancer? Generally, it is recommended that people above the age of 50 are screened for this cancer. However, for those with a family history of colon cancer, screening should be performed earlier.
The screening of colorectal cancer is only for people with no symptoms at all. People with symptoms suggestive of colorectal cancer should see a doctor for colonoscopy.
The mainstay of treatment for colorectal cancer is surgery. However, in more advanced stages of the disease, chemotherapy is given before surgery to shrink the cancer. The chance of a cure is high for early stages of colorectal cancer if patients receive appropriate treatment. Many new and more powerful chemotherapy drugs have been developed over the past two decades. These chemotherapy drugs have greatly improved the survival rate for patients after surgery.
There has been much advancement in the surgical treatment of colorectal cancer. Key-hole (or laparoscopic) surgery for colorectal cancer has taken centre stage over the past 10 years as many studies have shown that it is comparable to traditional open surgery in improving the survival rate for patients. At the frontier of this key-hole surgery are single port surgery and robotics surgery, which offer better cosmetic and functional outcomes for patients. In single port surgery, there is only one small scar of about 3 centimeters made, compared to more than a 15 centimeter scar in traditional open surgery.
Dr. Ng Kheng Hong is a colorectal and general surgeon at Gleneagles Medical Centre, Singapore