What’s Cancer
Cancer refers to a class of diseases caused by uncontrollable division, infiltration and spread of abnormal cells in the body. While it remains the number 1 killer in Hong Kong, thanks to advances in cancer screening, diagnosis and management, the survival rates and prognoses have been improving over the past decades.
The causes of cancer are mostly unknown. While it is difficult to pinpoint a definite and single cause for many cancers, in general there are 4 groups of possible environmental risk factors:
- Virus, e.g. human papilloma viruses are responsible for cervical cancers
- Chemicals, e.g. cigarettes, alcohol
- Radiation, e.g. UV light, prior radiotherapy
- Hormones
The term “stage” refers to the extent of cancer, tumour size and metastasis (if any). The most widely used cancer staging system is TNM (T: Tumour, N: Node; M: Metastasis).
Age is one of the major risk factors of cancer. Recent statistics and research show that the risk of certain cancers, e.g. breast and colorectal cancer, increases with age. According to the Cancer Online Resource Hub, more than 50% of cancers were diagnosed in people aged 65 or above in 2021, compared with a mere 0.5% in children and adolescents (i.e. aged 0–19 years).
In the 65–74 age group, the most common cancer was prostate cancer for males and breast cancer for females. Among people aged 75 or older, the most common cancer was lung cancer for both genders.
Generally speaking, cancers arise by chance or by hereditary. The fact that cancer can be unpredictable, however, does not mean that it cannot be prevented or cured if diagnosed at the earliest opportunity. You can definitely lower the risk of getting cancer with a healthy lifestyle, less exposure to carcinogens (e.g. excessive sunlight exposure) and regular screening.
A healthy lifestyle means, among others:
- Refraining from smoking and avoiding second-hand smoke;
- Minimising alcohol consumption;
- Having a balanced diet, e.g. more fruit and vegetables, less red meat and processed meat; and
- Exercising regularly.
Some people are genetically predisposed to certain kinds of cancer (e.g. breast, ovarian and colorectal cancer) due to gene mutations. The incidence of hereditary cancer is rare, and genetic testing is available as prevention and precaution measures.
Genetic testing is now available for those rare cases of hereditary cancers. You are advised to consult a related specialist if you have a family history of these cancers. It is especially recommended for those with relatives diagnosed with certain cancers at an unusually young age.
Certain cancers, such as ovarian cancer and those that have spread to distant organs (e.g. metastatic breast cancer) may not be cured completely. They may become a chronic illness like diabetes, which requires regular surveillance and treatment to prevent it from growing or spreading. Remission is not impossible, i.e. absence of tumour or size reduction for at least a month.