What is Colorectal Cancer?
Colorectal cancer refers to cancers developing in the colon or rectum. The colon is also known as the large intestine or large bowel. The colon is connected by a passage called the rectum which leads to your anus. Colorectal cancer starts typically as polyps (abnormal growths inside) but you must get them removed because they may become life-threatening later on.
Colorectal cancer is now one of the commonest cancers in Singapore. The numbers have gone up steadily among both men and women recently too! Fortunately, our mortality rates are dropping due to more people going through screening early on which can help find this deadly disease before it's irreversible. Treatment has also improved a lot thanks to innovations that make them more effective especially if found earlier.
Common symptoms of colorectal cancer
Colorectal cancer is also called colon cancer. Symptoms of colon cancer might not manifest in its earliest stages. However, as it progresses, symptoms become more noticeable. The following are signs and symptoms that you should not take for granted:
- Constipation or diarrhea which does not resolve within 2 weeks despite treatment
- Blood presence on the stool
- Abdominal pain, bloating and cramping
- Fatigue and weakness
- Iron deficiency anemia
- An urge to have a bowel movement despite having one already
What is colon cancer?
Colon cancer is a type of cancer that starts in the large intestine or colon. Though it can happen at any age, colon cancer usually affects older adults. However, the age of diagnosis of colon cancer is becoming younger in many developed countries, including Singapore.
Colon cancer causes
In general, colon cancer starts when healthy cells develop changes in their DNA. When a cell’s DNA suffers damage, it becomes cancerous and continues to divide even if new cells are not needed. The accumulation of these cells forms a tumor. Over time, cancer cells can grow and start destroying nearby normal tissues, and as they travel to other parts of the body, they form deposits on those parts.
Who’s at risk for colorectal cancer?
As people get older, their risk of colorectal cancer increases. Although it can occur in young adults, the majority of cases are diagnosed in people who are older than 50 years of age. Other risk factors include:
- History of polyps or colorectal cancer -- people who have a previous history of colon cancer or pre-cancerous colon polyps possess a higher risk of colorectal cancer.
- Inherited syndromes -- people who have an inherited syndrome of hereditary nonpolyposis colorectal cancer (HNPCC) or other polyposis syndromes are also at a higher risk of getting colorectal cancer.
- Diabetes -- individuals who suffer from diabetes or resistance from insulin.
- Idle lifestyle -- people who are known to have a sedentary lifestyle, or lack of activity are more likely to develop this type of cancer. Getting involved in regular exercise or other physical activities may lessen the risk of colorectal cancer.
- Smoking -- there is an increased risk for people who smoke.
- Alcohol -- heavy drinkers of alcohol products are at increased risk of getting colon cancer.
- Cancer patients who have undergone radiation therapy -- there is a risk for those people who have been treated by radiation therapy directed at the abdomen or pelvis.
What Should I Know About Screening for Colorectal Cancer?
When an individual shows no symptoms, a screening test is conducted to look for possible disease. This is different from a diagnostic test. If the person already has the symptoms, a diagnostic test is performed to determine the cause of the symptoms. Currently, the commonest methods for screening of colorectal cancer in Singapore are a stool test called faecal immunochemical test (FIT) and colonoscopy. Colonoscopy is the gold standard test.
How is colorectal cancer diagnosed?
Aside from physical examination, different tests can be used to diagnose colorectal cancer.
- Colonoscopy – The Singapore population has one of the highest incidence of colorectal cancer in Asia, along with Taiwan, Japan, and South Korea. Fortunately, there are many endoscopy specialists in Singapore and access to colonoscopy here is among the best in Asia. Colonoscopy is often performed in determining possible causes of conditions like rectal bleeding, abdominal pain, or changes in bowel movements. It is also an effective method to determine the presence of colorectal cancer.
- Biopsy -- a biopsy is a procedure used by doctors to determine whether the body’s abnormalities are caused by cancer or other conditions. A biopsy from a suspected colorectal cancer can be obtained during colonoscopy.
- Blood tests – a blood tumour marker called CEA is often elevated when a person has colorectal cancer. However, it is only useful once colorectal cancer has been confirmed. Your doctor will also need to know how well your liver and kidneys are functioning in order to determine how best to treat you.
- Radiologic tests – When a colonoscopy cannot be performed, colorectal cancer can be diagnosed with CT or MRI scan of the abdomen. If colonoscopy confirmed a colorectal cancer, a scan will still be required to determine the stage of the cancer and to plan treatment.
What are the treatment options for colorectal cancer?
There are various treatment approaches for colorectal cancer. However, adults over 50 years of age may have different treatment challenges. Listed below are the main types of colorectal cancer treatment:
- Surgery - often called surgical resection, surgery is the process of removing the tumor and adjacent colon or rectum. This will also involve removal of the blood vessels to that segment of colon and its lymph nodes.
- Radiation therapy -- radiation therapy is the utilization of high-energy x ray beams to destroy cancer cells. This is most commonly used for rectal cancer treatment since this type of tumor tends to reappear almost near where it happened.
- Chemotherapy -- the purpose of chemotherapy is to destroy cancer cells by the use of drugs. It prevents the cancer cells from dividing into more cells. After a successful surgery, chemotherapy may be provided to the patients to destroy any remaining cancer cells.
Cancer recovery is not always possible. In case cancer cannot be controlled or cured, it is referred to as advanced or terminal cancer. The best thing to do is to avoid having one. Living a healthy lifestyle coupled with active physical activity would drastically lessen the occurrence of cancer. Screening for colorectal polyps or cancer before you have developed symptoms also helps reduce your risk of colorectal cancer.