Health Corner

What is Colorectal Cancer?

Colorectal cancer is one of the most common cancers, and in recent years, it has become noticeably more prevalent among younger people.
In the past, cases in people under 40 were extremely rare, but now there are reports of men in their twenties being diagnosed with late-stage colorectal cancer. This trend is closely linked to Westernized dietary habits.

Colorectal cancer often begins with a small polyp—an abnormal growth on the inner wall of the colon—that can gradually turn cancerous over time.
Early detection greatly improves treatment success. According to research by the University of Hong Kong, in Stage 1, cancer cells usually invade only the muscle layer of the colon wall, and the five-year survival rate can exceed 90%. However, by Stage 4, the cancer has often spread beyond the intestine to other organs, reducing the five-year survival rate to about 8%.

Why Should You Take a Fecal Occult Blood Test (FOBT)?

In the early stages, colorectal cancer often causes no symptoms or warning signs.
The fecal occult blood test is a convenient, non-invasive screening tool that detects hidden (microscopic) blood in stool samples.
When a tumor develops in the colon, small amounts of blood—often invisible to the naked eye—may mix with feces as it passes through.

Participants can easily collect a small stool sample at home using a provided kit and return it to the clinic for lab analysis.
Regular screening is recommended for adults aged 25 and above.

A positive result indicates blood was detected but does not necessarily mean colorectal cancer is present. Other conditions—such as gastrointestinal ulcers, polyps, tumors, or hemorrhoids—can also produce positive results. Based on test findings, the doctor may refer the patient for a colonoscopy for further investigation.

Do I Still Need Regular Colonoscopy If I’ve Done the FOBT?

Yes. The fecal occult blood test is not 100% accurate.
Because only a small portion of stool is sampled and tumors may not bleed consistently, a result showing “no blood detected” does not completely rule out disease.

For individuals with a family history of colorectal cancer or other high-risk factors/symptoms, doctors may still recommend regular colonoscopy, which provides direct visualization of the colon and higher diagnostic accuracy.

Does the Government Subsidize Colorectal Cancer Screening?

Yes.
If you or a family member is aged 50 to 75 (born between 1944 and 1970), you are eligible for the government-subsidized Colorectal Cancer Screening Programme, which provides approved testing and follow-up care.

More details:
Hong Kong Colorectal Cancer Screening Programme
https://www.colonscreen.gov.hk/tc/public/index.html

HKU Research on Cancer Stem Cells Driving Colorectal Cancer Metastasis
https://www.med.hku.hk/f/news/502/810/75.pdf