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Cancer
By peace | October 27, 2005
What is cancer?
Throughout our lives, healthy cells in our bodies divide and replace themselves in a controlled sequence. Sometimes, however, a cell begins to reproduce abnormally for no apparent reason. A tumour or lump is a cluster of these abnormal cells. Often a cell from this lump or tumour spreads to another part of the body and begins reproduction there. Eventually this abnormal tissue interferes with the ability of the body and its cells, organs and other structures to perform their normal function, and illness or death may result.
Tumour formation
Most cancers form tumours. Malignant or cancerous tumours crowd out the healthy cells in the body, interfere with body functions, draw nutrients from body tissues and form new tumours in other parts of the body. The spread of cancerous cells is a process called metastasis.
The term ‘cancer’ is actually applied to more than 100 diseases that affect nearly every part of the body. All can be potentially life-threatening. They all have different causes, cause different symptoms, and vary in aggressiveness (the speed at which they spread). However, most types of cancer fall into 4 main categories.
- Carcinomas — these are the most commonly diagnosed cancers that affect the skin, mucous membranes, lungs, breasts, pancreas and other organs and glands.
- Leukaemias — these are cancers of the blood and blood-forming tissues and do not form solid tumours.
- Sarcomas — these are cancers that affect the bones, muscle and connective tissue and include many of the rarer forms of cancer.
- Lymphomas — these are cancers that affect the lymphatic system.
What causes cancer?
At present it is not known what exactly causes some cells to produce cancerous cells. For a healthy cell to turn malignant, its genetic code must be changed or reprogrammed for constant, uncontrolled cell division. Substances that either start or promote the process are called carcinogens, and there are many types.
What are the symptoms?
Cancers appear in many different ways. Most often they are noticed as a lump or growth in some part of the body. This is the case with tumours that form on the outlines of organs. When the cancerous growth is not physically identifiable, there may be other revealing symptoms depending on the form of cancer and the affected organ.
Cancer in the brain may have symptoms like headache, vomiting, difficulty in walking, paralysis and memory problems. Tumours of the intestine can present problems in bowel movements and pain in the stomach. Lung cancers may be manifested by difficulty in breathing and cough. Cancers of the breast are detected as a painless lump. There may also be some deformity of one or both breasts in some cases.
Some malignant tumours are manifested by abnormal bleeding from the affected organ. For example, cancer of the intestine may result in loss of blood in stools. Similarly, lung cancer may be detected when the patient passes blood in the sputum. Pain, as popularly believed, is not a common symptom of cancer. It only occurs in some cases where a nerve is pressed due to rapid enlargement of a tumour.
Other symptoms that may be common to all forms of cancer are a lack of appetite, unexplained loss of weight, general feeling of weakness and fatigue and increased proneness to infections.
Environmental factors
Environmental factors and diet are now thought to be 2 of the major causes of cancer. For example, people exposed to cigarette smoke have significantly higher rates of lung cancer than other people. Smoking is also linked to cancer of the head and neck areas, bladder, kidney, stomach, cervix and pancreas, as well as some leukaemias. Another environmental factor is overexposure to sunlight, causing several types of skin cancers. Many substances in the environment have been identified as carcinogens but, generally, high levels or long-term exposure are needed to cause cancer. These types of environmental carcinogens include various chemicals, gases and other substances found in the air, water and food.
Diet and nutrition
A diet that is high in fat and low in fibre is associated with a greater risk of colorectal cancer and is now considered a factor in several other cancers. Other dietary habits associated with cancer include over-consumption of alcohol, fat and foods that have been smoked, cured, pickled or charred.
Age and genetics
The risk for most cancers increases with age. Inherited, or familial, predisposition is also considered a risk factor, although the influence will vary from case to case.
All these factors may contribute to cancer; however, cancer is not actually caused by any single factor. Cancer most commonly is caused by a multiple of factors including age, inherited predisposition, general health and exposure to carcinogens. As such, everyone’s cancer risk profile is complex and unique.
Diagnosis of Cancer
In case blood is passed in stools or cough, the patient should see a doctor. For confirmation, a biopsy of the affected organ is done. In this procedure, a small part of the tissue is taken for laboratory testing to detect the presence of cancerous cells.
In case of cancer of the lungs, liver, stomach or intestine, an X-ray or ultrasound of the area may be taken. CT scans of the organs may also be done for diagnosis. The diagnosis is always made keeping in mind the patient’s previous medical history.
Treatment of Cancer
Treatment is most effective if the cancer is detected early. Chemotherapy is the most common method of treatment for cancer that has spread to other parts of the body. In this procedure, the malignant cells are destroyed with the help of powerful chemicals like methotrexate and vincristine which are given intra-venously i.e. directly injected into the veins. This procedure requires a hospital stay for the duration of therapy. It is also associated with various side effects like loss of hair, nausea, vomiting, loss of appetite and weakness for some days.
For a tumour that has not spread, radiotherapy or radiation, or surgery may be done. In the former, the cells are destroyed with the help of strong radio active waves. The exact position of the tumour is marked and the area is exposed to radiation under strictly controlled conditions. This treatment is given in breaks and in pre-determined doses.
Tumours that develop in organs under hormonal control like the breast, thyroid or prostate, may also be treated with endocrine therapy. In this treatment, either the source of the hormone is removed or anti-hormone drugs are given. This treatment scores over chemotherapy because it usually has less severe side effects. But the doctor decides the best course of treatment depending on the diagnosis of the form of cancer.
Topics: Diseases |
