World Cancer Day: A leading international awareness day
World Cancer Day every 4 February is the global uniting initiative led by the Union for International Cancer Control (UICC). They look to raise worldwide awareness, improve education and catalyse personal, collective and government action in order to reimagine a world where millions of preventable cancer deaths are saved and access to life-saving cancer treatment and care is equal for all - no matter who you are or where you live. So, let us have a brief look at cancer and what we can do about it.
Some Key Cancer Facts
- 9.6 million people die from cancer every year.
- At least one third of common cancers are preventable.
- Cancer is the second-leading cause of death worldwide.
- 70% of cancer deaths occur in low-to-middle income countries.
- Up to 3.7 million lives could be saved each year by implementing resource appropriate strategies for prevention, early detection and treatment.
- The total annual economic cost of cancer is estimated at US$1.16 trillion.
What is cancer?
Cancer is a disease which occurs when changes in a group of normal cells within the body lead to uncontrolled, abnormal growth forming a lump called a tumour; this is true of all cancers except leukaemia (cancer of the blood). If left untreated, tumours can grow and spread into the surrounding normal tissue, or to other parts of the body via the bloodstream and lymphatic systems, and can affect the digestive, nervous and circulatory systems or release hormones that may affect body function.
Types of cancers
Cancer can be classified according to the type of cell they start from. There are five main types:
Carcinoma – A cancer that arises from the epithelial cells (the lining of cells that helps protect or enclose organs). Carcinomas may invade the surrounding tissues and organs and metastasise to the lymph nodes and other areas of the body. The most common forms of cancer in this group are breast, prostate, lung and colon cancer.
Sarcoma – A type of malignant tumour of the bone or soft tissue (fat, muscle, blood vessels, nerves and other connective tissues that support and surround organs). The most common forms of sarcoma are leiomyosarcoma, liposarcoma and osteosarcoma.
Lymphoma and Myeloma – Lymphoma and Myeloma are cancers that begin in the cells of the immune system. Lymphoma is a cancer of the lymphatic system, which runs all through the body, and can therefore occur anywhere. Myeloma (or multiple myeloma) starts in the plasma cells, a type of white blood cell that produces antibodies to help fight infection. This cancer can affect the cell's ability to produce antibodies effectively.
Leukaemia – Leukaemia is a cancer of the white blood cells and bone marrow, the tissue that forms blood cells. There are several subtypes; common are lymphocytic leukaemia and chronic lymphocytic leukaemia
Brain and spinal cord cancers – these are known as central nervous system cancers. Some are benign while others can grow and spread.
Causes of cancer
Cancers can be caused by a number of different factors and, as with many other illnesses, most cancers are the result of exposure to a number of different causal factors. It is important to remember that, while some factors cannot be modified, around one third of cancer cases can be prevented by reducing behavioural and dietary risks.
| Modifiable Risk Factors |
| Alcohol – The evidence that all types of alcoholic drinks are a cause of a number of cancers is now stronger than ever before. Alcohol can increase the risk of six types of cancers, including bowel (colorectal), breast, mouth, pharynx and larynx (mouth and throat), oesophageal, liver and stomach. The evidence suggests that in general, the most alcohol drinks people consume the higher the risk of many cancers, and that even moderate alcohol intake increases the risk of cancer. |
| Being overweight or obese – excess weight has been linked to an increased risk of developing 12 different cancers, including bowl and pancreatic cancers. In general, greater weight gain, particularly as adults, is associated with greater cancer risks. |
| Diet and nutrition – Experts suggest that diets and nutritional intake, particularly diets high in red meats, processed meats, salted foods and low in fruits and vegetables have an impact on cancer risks, particularly colorectum, nasopharynx and stomach. |
| Physical activity – regular physical activity not only helps to reduce excess body fat and the cancer risks associated with this, but being physically active can help to reduce the risks of developing colon, breast and endometrial cancers. |
| Tobacco – Tobacco smoke contains at least 80 different cancer-causing substances (carcinogenic agents). When smoke is inhaled the chemicals enter the lungs, pass into the blood stream and are transported throughout the body. This is why smoking or chewing tobacco not only causes lung and mouth cancers but is also related to many other cancers. The more a person smokes, the younger they start, and the longer they keep smoking, all further increase the risk of cancer. Currently tobacco use is responsible for around 22% of cancer deaths. |
| Ionising radiation – Manmade sources of radiation can cause cancer and are a risk for workers. These include radon, x-rays, gamma rays and other forms of high-energy radiation. Prolonged and unprotected exposure to ultraviolet radiations from the sun, sunlamps and tanning beds can also lead to melanoma and skin malignancies. Fair skinned people, individuals with a lot of moles or who have a family history of melanoma or non-melanoma skin cancer, are at highest risk. However, people of all skin tones can develop skin cancer, including individuals with darker skin. |
| Infection – Infectious agents are responsible for around 2.2 million cancer deaths annually. This does not mean that these cancers can be caught like an infection; rather the virus can cause changes in cells that make them more likely to become cancerous. Around 70% of cervical cancers are caused by Human papillomavirus (HPV) infections, while liver cancer and Non-Hodgkin Lymphoma can be caused by the Hepatitis B and C virus, and lymphomas are linked to the Epstein-Barr virus. Bacterial infections have not been thought of as cancer-causing agents in the past, but more recent studies have shown that people who have helicobacter pylori infection of their stomach develop inflammation of the stomach lining, which increases the risk of stomach cancer. |
| Non-modifiable Risk Factors |
| Age – Many types of cancer become more prevalent with age. The longer people live, the more exposure there is to carcinogens and the more time there is for genetic changes or mutations to occur within their cells. |
| Cancer-causing substances (carcinogens) – are substances which change how a cell behaves, increasing the chances of developing cancer. Genes are the coded messages inside a cell that tell it how to behave (i.e. which proteins to make), mutations or changes to the gene, such as damage or loss, can alter how that cell behaves making it more likely to be cancerous. |
| Genetics – Some people are unfortunately born with a genetically inherited high risk for a specific cancer ('genetic predisposition). This does not mean developing cancer is guaranteed, but a genetic predisposition makes the disease more likely. For example, women that carry the BRCA 1 and BRCA 2 breast cancer genes have a higher predisposition to developing this form of cancer than women with a normal breast cancer risk. However, less than 5% of all breast cancer is known to be due to genes. So, although women with one of these genes are individually more likely to develop breast cancer, most cases are not caused by a high risk inherited gene fault. This is true of other common cancers where some people have a genetic predisposition - for example, colon (large bowel) cancer. |
| The immune system – People who have weakened immune systems are more at risk of developing some types of cancer. This includes people who have had organ transplants and take drugs to suppress their immune systems to stop organ rejection, plus people who have HIV or AIDS, or other medical conditions which reduce their immunity to disease. |
Preventing cancer
Over a third of all cancers can be prevented by reducing your exposure to risk factors such as tobacco, obesity, physical inactivity, infections, alcohol, environmental pollution, occupational carcinogens and radiation.
Prevention of certain cancers may also be effective through vaccination against the Hepatitis B Virus (HBV) and the Human Papilloma Virus (HPV), helping to protect against liver cancer and cervical cancer respectively.
Reducing exposures to other carcinogens such as environmental pollution, occupational carcinogens and radiation could help prevent further cancers.
For any further information or to make an appointment to see a Sister or Doctor at Campus Health Service, call 021 808 3494/6 (Stellenbosch Campus) or 021 938 9590 (Tygerberg Campus).