Colorectal cancer affects men and women equally, and is the most common cancer amongst Singaporeans - about 1200 new cases of colorectal cancer are diagnosed each year!
In this article, I explain some of the most common questions my patients ask me about colorectal cancer and screening in Singapore.
- Why cancer screening is important for early detection of colorectal cancer
- What symptoms you should look out for in colorectal cancer
- The latest treatments available for colorectal cancer
What is colorectal cancer, and what causes it?
Colorectal cancer is a cancerous tumor of the large intestine and rectum.
Many of my patients come into clinic thinking that a bad diet causes colorectal cancer. This was exactly what doctors thought in the past too - ie, that a diet high in fat and low in fibre contributes to colorectal cancer.
However, we now know that your genes are one of the most important contributing factors to colorectal cancer.
Studies have shown that many patients who go on to develop colorectal cancer have abnormal genes that cause the growth of polyps, which can turn cancerous.
Apart from "bad genes", certain inflammatory bowel diseases such as ulcerative colitis can also lead to colorectal cancer.
What are the symptoms of colorectal cancer?
To my patients' surprise, early colorectal cancers have very few symptoms.
It's also a common misconception that such cancers will cause you to bleed significantly.
In fact, most people with colorectal cancer do not even notice any bleeding at all. This is because any blood due to the cancer tends to get mixed in with stools.
Furthermore, the colon is very large, and can "accommodate" a growing tumour for a long time before any symptoms of obstruction (like difficulty passing motion) appear.
Early colorectal cancers are very small, and therefore will not cause any feeling of bloating or distention. By the time it causes any symptoms such as pain, the cancer is usually very advanced.
Colonoscopy - the best screening method for colorectal cancers
Since there are no practical preventive measures for colorectal cancers, and early curable cancers have virtually no symptoms, screening is the only way to detect early tumors and improve the chances of cure.
There are many ways of screening for colorectal cancers, most of which are not very accurate. These include:
- Barium enema X-rays
- Finger tests by an experienced doctor
- Fecal occult blood tests for colon cancer (FOBT).
The most accurate test for colorectal cancer screening is a fiberoptic colonoscopy. This method allows detection of even small 3mm polyps.
The procedure involves passing a soft tube with a camera into the rectum and colon. Your entire large intestine is then visualized on a TV monitor.
What age should you screen for colorectal cancer in Singapore?
According to the colorectal cancer screening guidelines of the Ministry of Health in Singapore, in conjunction with worldwide health authorities, recommends that you start screening starting at the age of 50.
If you have a family history of colorectal cancer, your screening should begin at age 40.
Latest treatment for colorectal cancer - keyhole surgery
The best treatment for colorectal cancer is surgery.
With rapid advancement of surgical technique and instruments, cancer surgery may be carried out using keyhole (laparoscopic) surgery.
The benefits of smaller incisions are that this results in less pain and a quicker recovery. With keyhole surgery, most patients are able to be discharged after 5 days.
Advanced stage cancers will require chemotherapy to complement surgery to improve the cure rate.
In summary, colorectal cancer is now a common disease. The best way to detect early colorectal cancer is a simple colonoscopy.
Early cancer has almost no symptoms, but has the highest chance for a complete cure after surgery. Laparoscopic surgery is currently the most advanced way to remove the tumor and allows faster recovery and discharge from hospital.
Dr Wong Nan Yaw is a Fellow with the Academy of Medicine (Singapore) and also a Member of the Society of Colorectal Surgeons (Singapore). NY Wong Surgery focuses on the diagnosis and therapy of both benign and malignant conditions of the colon, rectum and anus. He is also well-versed in general surgical conditions like gallstones and abdominal wall hernias.
1. Colorectal cancer screening. Singapore Medical Journal.
2. National Registry of Diseases Office (NRDO), Health Promotion Board, Singapore Cancer Registry Annual Registry Report Trends in Cancer Incidence in Singapore 2010 – 2014 [online]. Available at: https://www.nrdo.gov.sg/docs/librariesprovider3/default-document-library/cancer-trends-report-2010---2014_web.pdf?sfvrsn=0.