Health Corner

There are many types of cancer screening methods available today—from traditional imaging tests and tumor marker blood tests to the recent development of mRNA “liquid biopsy” blood tests. Each has its own applications and limitations.
To choose the most suitable test, it’s important to understand how they work, their accuracy, and who they are best suited for.

What are the common types of cancer screening tests?

1. Tumor Marker Tests (Cancer Marker / Tumor Marker)

Doctors often use blood tests to measure tumor markers, which help assess cancer risk, monitor treatment response, or detect recurrence. These markers are specific substances—such as alpha-fetoprotein (AFP) or carcinoembryonic antigen (CEA)—produced by cancer cells or by the body in reaction to them.

Note: Tumor marker levels can be influenced by other factors like inflammation, smoking, and general health conditions. This may lead to false positives or false negatives. Therefore, such tests are mainly used for preliminary screening and ongoing monitoring, rather than definitive diagnosis.

2. Imaging Examinations (X-ray, Ultrasound, CT, MRI, PET-CT)

This is one of the more traditional yet essential cancer diagnostic methods. Different imaging tools allow clinicians to “see” the location and size of tumors inside the body, and can be selected according to specific organs or health concerns:

• X-ray / Ultrasound: Commonly used for initial examination of the chest, abdomen, and breasts.

• CT / MRI: Provides clearer cross-sectional images for detailed tumor evaluation.

• PET-CT: Uses radioactive tracers to show metabolic activity of tumors, often for staging and metastasis assessment.

Note: These methods usually detect tumors once they grow to about 0.5–1 cm, meaning smaller ones may go unnoticed. Some imaging tests also involve radiation exposure and tend to have higher costs.

3. Blood-Based Tests (cfDNA / ctDNA, microRNA, CancerSEEK)

Recent advancements in “liquid biopsy” technology allow cancer detection through a simple blood draw, by analyzing circulating tumor DNA (ctDNA), microRNA, or gene mutations together with tumor protein markers.

For instance, CancerSEEK can simultaneously detect multiple gene mutations and cancer-related proteins.
In research, it has shown an overall 70% sensitivity and over 99% specificity for eight types of cancer.
These tests are still emerging technologies, mainly used for high-risk screening and research, with clinical applications currently expanding.

Is the microRNA (mRNA) method more suitable for me?

mRNA testing detects tumor-related signals through a blood sample.
Because mRNA (messenger ribonucleic acid) is the molecule that carries genetic instructions from DNA to produce proteins, cancer cells also exhibit distinctive mRNA expression patterns.
If malignant tumors exist, circulating tumor cells and their mRNA signatures can be found in the bloodstream.
mRNA testing analyzes these specific tumor-related mRNA markers to determine whether there is active tumor cell activity within the body.

mRNA testing may be suitable for:

• People with a significant family history of cancer or genetic predisposition

• Those seeking a higher-sensitivity option for early cancer detection

• Post-treatment patients who wish to monitor for recurrence (consult your doctor)

• Individuals who prefer low-radiation and less frequent screening options due to work or lifestyle factors

What are the advantages of mRNA testing?

• Requires only a small blood sample, non-invasive and simple to perform.

• Can detect very small tumors (≥0.2 cm) or early-stage changes, earlier than traditional imaging.

• High accuracy, sensitivity, and specificity, with overall accuracy often exceeding 90%.

• Suitable for assessing multiple cancer types, and can be combined with other tests for comprehensive evaluation.

What types of cancer can mRNA testing detect?

mRNA technology can detect a wide range of cancers, including those common among both men and women in Hong Kong such as cervical cancer and prostate cancer.
Other detectable cancers include:

• Breast cancer

• Stomach cancer

• Nasopharyngeal cancer

• Colorectal cancer

• Lung cancer

• Pancreatic cancer

• Head and neck cancers

• Liver cancer

You can choose specific mRNA tests based on your personal risk areas. Human Health offers several cancer risk assessment programs available on its online store, including:

• Early Nasopharyngeal Cancer Screening (HCENPC01): HK$1,500 (original HK$1,700)

• Lung Cancer Risk Assessment (HCIMP017): HK$1,800 (original HK$2,840)

• Gastrointestinal Cancer Risk Assessment (HCECC01): HK$1,300 (original HK$2,200)

• Breast and Cervical Cancer Risk Assessment (HCEBC01): HK$4,000 (original HK$6,030)

All programs can be purchased through the Human Health eShop.
For inquiries, please call the service hotline at 2397 2111.

Although mRNA testing typically costs more than traditional tumor marker tests, it remains more affordable than many high-end imaging scans.
It can be considered a mid-priced, high-precision screening option, offering an additional “blood test for cancer” pathway that may reveal potential tumor risks at an earlier stage.
This helps high-risk individuals seek timely follow-up and intervention.
If you have any concerns, it’s best to consult your doctor before deciding which test is right for you.