Body: What is Cancer?
Cancer as a term, is derived from the Greek work for “crab”. Hippocrates, the ancient father of medicine, described the spread of a cancerous tumour to the shape of the claw of a crab. As a disease, cancer causes the uncontrollable growth of body cells as a result of damage caused to the body’s regulatory mechanisms.
The majority of cancerous tumours develop in a specific part of the body such as the skin, breast, lung, bowel or prostate gland in the form of a solid mass. It may also spread via the blood and lymphatic systems.
Cancer and Genetics
One of the most significant breakthroughs in cancer research was the discovery that cancer is caused by damage of the genetic material in the body. We have approximately 20,000-25,000 genes responsible for controlling the vital processes, including cell division in our bodies. A cell can become cancerous due to inherited tendencies or through exposure to carcinogens such as sunlight or tobacco smoke, although this is not always the case as the body’s immune system often destroys any abnormal cells before they are able to spread. More than one gene must be damaged before cancer develops. A cancerous tumour begins as a single cell and if it is not destroyed by the immune system, it multiplies uncontrollably. The growth rate of tumours, is measured by the time it takes for cells to double, known as the “doubling time” which varies from 1 month to 2 years.
Causes of Cancer
As cancers vary, so are the factors that cause them, the most common carcinogens are tobacco smoke, which is responsible for a third of all cancers. Smoking is the cause of lung cancer which has increased in epidemic proportions across the world. The table below highlights factors contributing to cancer:
Aging And Cancer
The disease is more common amongst older people, this is due to the cumulative genetic damage that occurs to cells over time and the reduction in the efficiency of the immune system as we age. Some tumours grow slowly and exist unnoticed for years without significant symptoms. With the increase in life expectancy in developed countries, cancer has risen to become one of the most common cause of death in the U.K.
A malignant tumour refers to a collection of abnormal cells which are generally dividing uncontrollably. As they continue to grow and spread, cancerous tumours infiltrate surrounding tissues by imposing upon normal cells. They can also spread rapidly to distant body parts via blood and lymph vessels. Cancer cells are characterised by their abnormal and irregular shape and size which stand out from the cells where they originated from.
Tumours can often form in epithelial tissue which covers the body and lines body cavities and organs, causing erosion and ulceration. Bleeding can often occur inside tumour due to the infiltration of blood vessels, particular where cells are fast-growing. Where cells involve nerve fibres, tumours can be painful. Cancerous cells may spread through the lymph vessels which are responsible for maintaining a healthy immune system and fight cancerous cells. When cancerous cells invade the lymphatic system, they divide and develop into a tumour.
Like any other cell, cancerous cells require adequate nutrition to grow. They obtain oxygen and nutrition from surrounding blood vessels, in the same way as normal cells. As the tumour enlarges, inner cells are starved. Tumours that enlarge, they gain nutrition by either invading blood vessels and by stimulating the growth of new blood vessels (known as angiogenesis).
Cancer often spreads to parts of the body which have a good blood supply such as the liver, lungs and bone. The liver is common site for cancer cells to infiltrate as it receives ample supplies from the heart and intestines.
When a cancerous tumour spreads to distant sites of the body, the process is called metastasis. In metastasis, a cancerous cell detaches from a tumour and travels in blood or via the lymph system and establishes itself in a new location. The assessment of the spread of cancer from its primary site to nearby lymph nodes or other sites of the body is known as “staging”. Staging allows doctors to determine the prognosis of a patient and plan the best treatment.
Symptoms of Cancer
Although cancer may be detected before any symptoms appear, it may be detected through routine screening. Usually, the disease causes symptoms which worsen as follows:
General symptoms include:
- A lump which is firm and painless, in or beneath the skin
- Changes in the appearance of a mole
- A non-healing wound
- Blood in urine or sputum
- Changes in bowel habits
- A discharge containing blood from the rectum or vagina
- Persistent abdominal pain
- Persistent cough
- Hoarseness or changes in the voice
- Difficulty in swallowing
- Severe, recurrent headaches
The experience of one or more of these symptoms, require follow up with the GP.
- Weight loss
- Unexplained tiredness
- Loss of appetite and nausea
Treatment and Management of Cancer
The general approach to treating cancer is the same for all people affected by the disease, regardless of the location of the tumour. The chances of curing cancer are highest when it is detected at its earliest stages. The 3 main treatment options for cancer sufferers are surgery, chemotherapy and radiotherapy. Other treatment methods involve biological and hormonal therapies.
When cancer is in its early stages, the aim of treatment is to cure. As the condition progresses treatment can slow the growth or be palliative, making the sufferer comfortable. Treatment is adapted to the type and extent of the cancer age, general health and personal wishes.
Surgery- is the most common form of treatment to remove tumour during the early stages of cancer.
Chemotherapy- uses anti-cancer drugs to kill cancerous cells. It is the key treatment for leukaemia and other cancers that are widespread in the body.
Radiotherapy- applies radiation directly to cancerous cells and tissues: to destroy them or slow their growth.
(source: © hopecalls.org)
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