Can cancer be detected before symptoms appear?
癌症探測是指身體出現有可疑症狀前就進行有關檢查，以及早評估癌症。而癌症普查是指通過有系統的方法，向無癌症病徵的人士進行檢測。換言之，癌症普查是指在並沒有癌症病徵的人群中找出患癌的人。
癌症探測/普查能及早發現癌病，有助提高診療成效，不同檢查項查各有特點，因此接受檢查前，必須清楚明白其中的意義。
Tumor markers
Tumor markers are usually glycoproteins. They are substances that some cancer cells produce during their growth and can be detected in a patient's blood, urine, or tissues. Changes in their levels can be used to identify the presence of a tumor. When cancer cells are present in the body, the concentration of tumor markers in the blood increases. However, other physiological factors or diseases may also cause an increase in such substances.
Imaging tests
X-ray
Clearly shows the contours of internal organs.
Ultrasound
Observes the real-time changes in organs.
Computed tomography (CT) scan
Obtains multiple cross-sectional images of specific parts of organs, which can be combined to form 2D and 3D images.
Positron emission tomography (PET) scan
Creates 3D colour images that can be combined with CT anatomical images and data to improve accuracy.
Magnetic resonance imaging (MRI)
Displays the morphology of soft tissues and nerve fibres with extremely high image contrast.
Genetic testing
For high-risk individuals with a family history of cancer, such as breast cancer, cervical cancer, or those with family members carrying BRCA mutation genes, genetic testing can also be considered as a cancer screening method under the advice of a doctor.
Other cancer screening tests
- Cervical cancer screening: Pap smear
- Colorectal cancer screening: faecal occult blood test/ sigmoidoscopy/colonoscopy
- Breast cancer screening: 3D mammography
Under the advice of a doctor, high-risk individuals and those with a family history of cancer can also consider targeted cancer screening tests to detect the disease early and improve the recovery rate.
The above information is for reference only. If you have any medical questions, please consult your doctor.
