Cancer is a leading cause of death worldwide and accounted for 7.6 million deaths (around 13% of all deaths) in 2008.
Each year on 4 February, the NHLS supports the WHO and the International Union Against Cancer to promote ways to ease the global burden of cancer. Preventing cancer and raising quality of life for cancer patients are recurring themes.
- Cancer is a leading cause of death worldwide, accounting for 7.6 million deaths (around 13% of all deaths) in 2008 (1).
- Lung, stomach, liver, colon and breast cancer cause the most cancer deaths each year.
- The most frequent types of cancer differ between men and women.
- About 30% of cancer deaths are due to the five leading behavioral and dietary risks: high body mass index, low fruit and vegetable intake, lack of physical activity, tobacco use, alcohol use.
- Tobacco use is the most important risk factor for cancer causing 22% of global cancer deaths and 71% of global lung cancer deaths.
- Cancer causing viral infections such as HBV/HCV and HPV are responsible for up to 20% of cancer deaths in low- and middle-income countries.
- About 70% of all cancer deaths in 2008 occurred in low- and middle-income countries.
- Deaths from cancer worldwide are projected to continue rising, with an estimated 13.1 million deaths in 2030 (2)
Cancer is a generic term for a large group of diseases that can affect any part of the body. Other terms used are malignant tumours and neoplasms. One defining feature of cancer is the rapid creation of abnormal cells that grow beyond their usual boundaries, and which can then invade adjoining parts of the body and spread to other organs. This process is referred to as metastasis. Metastases are the major cause of death from cancer.
Global burden of cancer
Cancer is a leading cause of death worldwide. The disease accounted for 7.4 million deaths (or around 13% of all deaths worldwide) in 2004. The main types of cancer leading to overall cancer mortality each year are:
- lung (1.3 million deaths/year)
- stomach (803 000 deaths)
- colorectal (639 000 deaths)
- liver (610 000 deaths)
- breast (519 000 deaths)
- More than 70% of all cancer deaths occurred in low- and middle-income countries. Deaths from cancer worldwide are projected to continue rising, with an estimated 12 million deaths in 2030.
The most frequent types of cancer worldwide (in order of the number of global deaths) are:
- Among men – lung, stomach, liver, colorectal, oesophagus and prostate
Among women – breast, lung, stomach, colorectal and cervical
What causes cancer?
Cancer arises from one single cell. The transformation from a normal cell into a tumour cell is a multistage process, typically a progression from a pre-cancerous lesion to malignant tumours. These changes are the result of the interaction between a person's genetic factors and three categories of external agents, including:
- physical carcinogens, such as ultraviolet and ionizing radiation
- chemical carcinogens, such as asbestos, components of tobacco smoke, aflatoxin (a food contaminant) and arsenic (a drinking water contaminant)
biological carcinogens, such as infections from certain viruses, bacteria or parasites
Some examples of infections associated with certain cancers:
- Viruses: hepatitis B and liver cancer, Human Papilloma Virus (HPV) and cervical cancer, and human immunodeficiency virus (HIV) and Kaposi sarcoma
- Bacteria: Helicobacter pylori and stomach cancer
- Parasites: schistosomiasis and bladder cancer
- Ageing is another fundamental factor for the development of cancer. The incidence of cancer rises dramatically with age, most likely due to a build-up of risks for specific cancers that increase with age. The overall risk accumulation is combined with the tendency for cellular repair mechanisms to be less effective as a person grows older.
- Tobacco use, alcohol use, low fruit and vegetable intake, and chronic infections from hepatitis B (HBV), hepatitis C virus (HCV) and some types of HPV are leading risk factors for cancer in low- and middle-income countries.
- Cervical cancer, which is caused by HPV, is a leading cause of cancer death among women in low-income countries. In high-income countries, tobacco use, alcohol use, and being overweight or obese are major risk factors for cancer.
What can you do to reduce your risk?
Knowledge about the causes of cancer, and interventions to prevent and manage the disease is extensive. Cancer can be reduced and controlled by implementing evidence-based strategies for cancer prevention, early detection of cancer and management of patients with cancer.
More than 30% of cancer could be prevented by modifying or avoiding key risk factors, according to a 2005 study by international cancer collaborators (Danaei et al). Risk factors include:
- tobacco use
- being overweight or obese
- low fruit and vegetable intake
- physical inactivity
- alcohol use
- sexually transmitted HPV-infection
- urban air pollution
- indoor smoke from household use of solid fuels
- Prevention strategies:
- increase avoidance of the risk factors listed above
- vaccinate against HPV and HBV
- control occupational hazards
- reduce exposure to sunlight
New South African Cancer Regulation
The National Cancer Registry (NCR), a specialised division of the NHLS, has been collating cancer statistics for South Africa since its establishment in 1986. However, reporting cancer data to the NCR was voluntary. These concerns were addressed and a new legislation was introduced by Dr. Aaron Motsoaledi, Minister of Health, on 26 April 2011, which requires all doctors and health facilities who confirm cancer cases to report their findings to the NCR.
What Can You Do?
- Sign the The World Cancer Declaration – this will help bring the growing cancer crisis to the attention of government leaders and health policy makers in order to significantly reduce the global cancer burden by 2020
- Get involved with CANSA – volunteer your time or services, support online fundraisers, share your story online or just support CANSA initiatives
- Be assertive! Get screened for early detection. Early detection of cancer greatly increases the chances for successful treatment. There are two major components of early detection of cancer: education to promote early diagnosis and screening. Recognizing possible warning signs of cancer and taking prompt action leads to early diagnosis.
Acknowledgements: some of the information contained in this article was sourced and modified from the WHO, UICC and CANSA websites.