The human body is made up of billions of cells, which in a healthy body are usually turning over slowly, in an organised way. The overgrowth of cells can cause a lump or a mass, which is called a tumour. Tumours can be benign or malignant.
Benign tumours usually grow slowly under control, and do not spread to other parts of the body. Benign tumours only become a problem if they grow very large, taking up space and affecting the way the body works. Malignant tumours are made up of cancer cells. Cancer cells grow in an abnormal and uncontrolled way. They are usually faster growing, can destroy tissue and have the ability to spread to other parts of the body.
Cancer may also affect blood cells, causing blood cancers such as leukaemia, lymphoma or myeloma. These blood cancers also cause reduced normal blood cell production due to the uncontrolled growth of the abnormal (malignant) cells in the bone marrow.
Over time, the uncontrolled growth of cancer cells usually becomes too much for the body to cope with, or will spread to a part of the body that is essential for life.
According to a report published in 2019 by Hong Kong Hospital Authority and the Government Food and Health Bureau there were over 30,000 new cases of cancer in 2017 in Hong Kong alone, with the projected annual number of cancer cases expected to increase by over 40,000 cases by 2030. With the continual increase in cancer cases it is increasingly important to understand cancer including screening and treatment options which will further improve survival rates.