What is cancer?
Cancer is a genetic disorder that is caused by abnormal cells that divide/multiply uncontrollably and spread to invade surrounding and distant structures. Cancer is the second leading cause of death globally, accounting for 1 in 6 deaths worldwide. Despite this dreadful statistic, up to 50% of all cancers can be prevented. This article will explain the basics of how cancer forms, the risk factors for getting cancer and the various means of prevention available.
How does cancer come about?
Every cell in the human body undergoes regular division. This is the underlying process of growth and maturity of organisms. This process is controlled by genetic material in the cell’s core. The control processes include start and stop signals and proofreading mechanisms to ensure that the process meets the required standard and produces normal cells every time division takes place.
Damage to any component of the genetic material that controls this normal cell division leads to formation of abnormal cells that aggregate (add up) to form a tumour. Some tumours are benign (harmless) because they are restricted to the site of formation e.g. uterine fibroids. Other tumours are malignant (dangerous) because they spread into surrounding tissues and later to distant tissues. In doing so, they replace normal cell function in the various sites they spread to and cause disease, disability and ultimately death, if left unchecked.
What makes one get cancer?
Damage to genetic material can be caused by physical, chemical and biological factors. Any time cells are exposed to these factors the risk of developing DNA changes that lead to cancer increases, they are therefore known as risk factors.
Physical risk factors for cancer include exposure to ionizing radiation such as gamma rays and repeated high intensity x-rays. Most types of radiation we are exposed to, fortunately, are non-ionizing and hence cannot cause damage to genetic material (DNA) e.g. radiofrequency waves, microwaves and infra-red.
Chemical risk factors include exposure to cigarette smoke, aflatoxins, arsenic, dioxins, aniline dyes and asbestos. Harmful, chronic use of alcohol also increases the risk of developing cancer. Nitrosamines are chemicals found in smoked food; this is known to increase the risk of stomach cancer in particular.
Biological risk factors include viruses that can alter cell DA such as human papilloma viruses (cervical cancer), Ebstein-Barr virus (Burkitts Lymphoma) and hepatitis B virus (hepatocellular cancer).
Aside from these external factors, internal risk factors for cancer include family history and repeated division. Some families already have partial damage to the genetic material and this is passed on from generation to generation. With members of such families they only need a little exposure to risk factors to trigger the process of cancer formation. That is why it is important to be aware of family history and of conditions such as breast cancer, ovarian cancer and prostate cancer.
In spite of all the aforementioned risks to developing cancer, the majority of people cannot trace their cancer development to any of the above. This is because most cases of cancer are caused by accumulation of genetic defects during the ageing process. With increasing age, the constant wear and tear hampers the effectiveness of the body’s DNA repair mechanisms. Eventually, these small DNA changes lead to a cell that has malignant potential and leads to cancer. Even for those who are exposed to risk factors, the abnormal cells are kept in check by the body till age-related deterioration of immune function lets the cancerous cells out of the bag to wreak havoc to the body.
How can one prevent cancer?
As serious as cancers are, there are various ways of preventing cancers from starting, spreading, and causing increased harm. These are the three tiers of prevention: primary, secondary and tertiary.
Primary prevention of cancer involves all that is done to prevent the disease from starting in the first place. This includes education about cancer and its risk factors that help people to reduce their exposure to such risk factors. In companies that work with potential carcinogens (cancer-producing substances) various safety measures are put in place to reduce the risk of harm.
Vaccination against viruses that are oncogenic like human papilloma virus (HPV) and hepatitis B are also part of primary prevention strategies employed against viruses. In families with a history of cancer, tests are done to identify members with particular genes noted to cause cancer. This has led to some women having preventive breast removal surgery (mastectomy) to prevent the development of breast cancer. All these measures are useful in preventing cancer formation.
Secondary prevention of cancer, however, is aimed at early detection of localized cancer with the aim of preventing its spread and possibly achieving cure by removing the initial cancer tissue. The various screening programs organized and advertised are part of this effort. If cancer tissues are noticed early, the affected tissue can be removed entirely before it spreads to other areas (metastasizes).
Prostate Specific Antigen (PSA) testing and annual examination are used to detect early prostate cancer (in men) while periodic pap smears are done to detect early cervical cancer (in women). Different methods are used in early detection of cancer, but not all cancers can be detected early. That is where tertiary prevention comes in.
Once cancer has established and begun to spread, the treatment goal is to limit the damage the cancer does to the body. This is called tertiary prevention. It involves doing tests to find areas of the cancer spread and undergoing procedures to limit the effect of the cancer.
When all fails, palliative care is treatment given to make a patient pain- and symptom-free until the inevitable happens. Anyone who has witnessed the pain cancer patients go through will attest to the indescribable pain and heartache it causes.
Cancer is a terrible disease but it can be prevented. Knowledge is the best treatment. Prevention starts from being informed about the risks of developing cancer and taking the necessary steps to stop the disease process before it starts.