There are over 100 different types of cancer. Each is named by the type of cell that is initially affected. Cancer is a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body. Cancer harms the body when mutated, or altered cells divide uncontrollably to form lumps or masses of cancerous tissue called tumours. Tumours can be cancerous (malignant) or not cancerous (benign).

Benign tumours stay in one spot and demonstrate limited growth. These are more easily treated than the more dangerous malignant tumours.

Malignant tumours occur when a cancerous cell manages to move throughout the body using the blood or lymphatic systems, destroying healthy tissue in a process called the invasion or if that cell manages to divide and grow, making new blood vessels to feed itself. This process is called angiogenesis.

Metastasis is a process that is caused when a tumour successfully spreads to other parts of the body and grows, invading and destroying other healthy tissues. Metastasised tissue is a serious condition and the most difficult to treat.

Source: National Cancer Institute

1. Genes
If your family has a high incidence of a specific type of cancer, it is possible that you inherited genetic mutations that increase your susceptibility to certain cancers. Breast and colorectal cancer are examples of cancers that tend to run in families. Nevertheless, having a genetic mutation does not necessarily guarantee that you will develop cancer in the future; only about 5 to 10 percent of all cancers are directly attributed to inherited genetic mutations.

2. Smoking
There are many carcinogenic substances found in tobacco smoke, which can increase your likelihood of developing certain types of cancer, such as lung and oral cancer, as well as stomach, kidney, and bladder cancer. Any form of tobacco consumption is detrimental to your well-being.

3. Exposure to Second-hand Smoke
Second-hand smoke is equally hazardous to health. When a cigarette is lit, approximately 90% of the smoke is released into the air, which then becomes second-hand smoke. Even if you don’t smoke, being exposed to someone else’s smoke can raise your risk of developing lung cancer.

4. Sun and UV Exposure
Regularly exposing your skin to ultraviolet (UV) radiation, whether from direct sunlight or artificial sources like tanning beds, can cause harm and increase your chances of developing skin cancer.

5. Alcohol
Drinking alcohol leads to a higher risk of cancer, regardless of the quantity. The less alcohol you drink, the lesser your risk of cancer.

Source: Singapore Cancer Society

Cancer is one of the leading causes of morbidity and mortality worldwide, with an estimated 18.1 million cancer cases worldwide in 2020. Of these, 9.3 million cases were in men and 8.8 million in women. The number of new cases is expected to rise to 27.5 million over the next 2 decades. Cancer is the second leading cause of death globally, accounting for an estimated 9.6 million deaths, or one in six deaths, in 2018.

Breast and lung cancers were the most common cancers worldwide, contributing 12.5% and 12.2% of the total number of new cases diagnosed in 2020. Colorectal cancer comes in third with 1.9 million new cases in 2020, contributing 10.7% of new cases.

The top three most common cancers in males are lung, prostate and colorectal cancers – contributing to 41.9% of all cancers (excluding non-melanoma skin cancer). Lung cancer was the most common cancer in men worldwide, contributing 15.4% of the total number of new cases diagnosed in 2020.

For females, the top three most common cancers are breast, colorectal and lung cancers – contributing to 44.5% of all cancers (excluding non-melanoma skin cancer). Breast cancer was the most common cancer in women worldwide, contributing 25.8% of the total number of new cases diagnosed in 2020.

Source: World Cancer Research Fund International and American Cancer Society