Hello, dear readers. Greetings to you all. This will be the final post of my series on HEALTH AND DISEASES. In this post, I will explain how cancer can be prevented and treated. I will also discuss the various types of lung disease.
Although drugs and food supplements to prevent cancer are a possibility, they are likely to take time to develop. In the meantime, changing your lifestyle could help you reduce the risk of cancer in later life. Four steps seem to be the most important:
- Never smoke. If you smoke, stop.
- Eat a well-balanced diet in which animal fat makes up less than 25 per cent of the calories. Include at least five portions of fresh fruit or vegetables every day, and try to obtain most of your protein from plant sources (e.g. beans, peas, grains). Avoid very salty or smoked foods and charred meats, particularly red meats.
- Take regular exercise and maintain a sensible weight.
- Drink alcohol in moderation.
Screening for cancer
Successful cancer treatment often depends on getting an early diagnosis. The longer a malignant tumour is left, the larger it grows and the more likely to spread and affect other organs. Surgery can be used to remove a localized tumour but it is of little use if the condition has spread throughout the body.
Skin cancer is one of the commonest forms of cancer in younger people but at least it is easily noticed. Surgical removal is very effective and results in 97 per cent of people surviving 5 years after the operation. Cancer of colon is a very different matter. There are no visible signs and early symptoms are vague. Most people don't take them seriously and end up visiting their doctors for the first time when the cancer is already quite advanced. Not surprisingly, the 5-year survival rate for this form of cancer is much lower, at only 37 per cent.
Regular screening can help to detect cancers early, but the advantage have to be weighed against its high financial cost. The NHS has screening programmes for two of the most common female cancers, breast cancer and cervical cancer. Breast cancer screening is carried out every 3 years by mammography. It targets women over 50 years old since breast cancer occurs most often in women over this age and because breast tissue in younger women is too dense for mammography to be effective. The breast cancer programme has probably caused a 20 per cent fall in death rate, simply because cancers have been picked up and treated early enough.
The national cervical screening programme was launched in 1988 and has cut deaths from cervical cancer by about 30 per cent. The programme recommends that a smear is taken every 3 years. Cells are stained and examined under a microscope, and those likely to become cancerous can be identified. Early treatment is then possible.
Screening programmes for other cancers might not be so effective. Prostate cancer is common, particularly in older men, and there are methods of identifying it at an early stage. These include using ultrasound or testing the blood for high concentrations of prostate-specific antigen or PSA, an enzyme secreted by cells in the prostate. An enlarged prostate gland produces more PSA than a healthy one.
But is screening cost effective? Can it be used to prevent cancer deaths? The answer to some extent depends on where you live and what kind of healthcare system you have locally. In the USA, where private medical insurance bears the cost, PSA screening is commonplace, even though there are little doubts about its reliability. Early treatment of prostate cancer is carried out routinely. In the UK, the cost of a general screening programme would be an enormous burden on the NHS and would save relatively few lives: most men with fully developed prostate cancer are very elderly and are usually at far higher risk of dying from some other condition.
Surgery, chemotherapy and radiotherapy are important cancer treatments. They are all constantly being improved by research and have varying success rates, depending on the type of cancer and its site in the body. Drug treatment for leukaemia in children, for example, now cures nine out of ten children. Lung cancer can be much less easy to treat: the lungs cannot be completely removed by surgery, and the tissue is delicate and easy to damage.
New strategies are approaching cancer treatment from several different angles; some of which are conformal radiation therapy, neutron and proton radiation therapy, immunotherapy, differentiating agents, angiogenesis inhibitors, oncogene blockers and gene therapy.
In addition to lung cancer and tuberculosis there are three other important diseases that can affect the lungs. These are asthma, emphysema and fibrosis: the latter can occur as a result of cystic fibrosis or other lung diseases.
Asthma is a common childhood ailment, affecting at least one in ten children, and a large number of adults. The number of asthma cases has been dramatically in recent years, fueling speculation that an increase in air pollution is to blame.
Put simply, asthma is a difficulty in breathing caused when the smooth muscles of the bronchioles contract, narrowing the airways that lead to the alveoli. Asthma sufferers then find it hard to breathe and have to make far more effort to deliver a normal amount of air to the lungs.
Many factors can cause asthma, including an allergic reaction (reaction of the immune system to a substance that, in non-sufferers, has no effect). Common allergens are house dust mite faeces, fur, feathers and pollen.
Several approaches are used together to help control asthma. A doctor's first priority with all but very young children is to explain what is happening inside the lungs. Sufferers will be less frightened and can come to terms with their problem. The worst physical effects of the condition are then controlled by a combination of drugs and prevention.
Generally, two types of drugs are prescribed to asthma sufferers: bronchodilators and steroids. Bronchodilators give instant relief from chest tightness and wheezing because they contain chemicals which relax the bronchiole walls. Many asthma sufferers carry a reliever inhaler around with them. It contains salbutamol or terbutaline, which both act as bronchodilators to relieve the feeling of being 'tight-chested'. This is very useful in the treatment of attacks and is safe to use frequently.
Many asthma sufferers also use a preventative inhaler that contains steroids. Steroids such as Becotide™ act by reducing the degree of inflammation of the bronchioles. Steroids are preventative: asthma sufferers take regular doses morning and night to reduce the problem of over-reaction. The amount of steroids taken is minimal but they are effective if taken according to instructions.
Fibrosis is a process by which normal tissues of an organ suffer damage and are replaced by fibrous connective tissue ('scar tissue'). The delicate alveoli of the lungs are particularly vulnerable to fibrosis. Widespread fibrosis due to smoking or other air pollution is called emphysema, while tuberculosis can leave small patches of fibrosis caused by bacterial infection. Thus. fibrosis is a consequence of disease rather than a disease in its own right.
Emphysema is a lung disease that results from gradual but relentless damage to the fragile alveoli in the lungs. When the delicate epithelial cells of the alveoli are damaged they are replaced with 'scar' tissue that is thick, tough and inelastic. This process is called fibrosis. The lungs have a smaller surface area and a thicker wall, so gas exchange is less efficient. The lungs area are also less elastic.
Normally, exhaling is largely a passive process, the elastic nature of the lungs forces air out without much help from the muscles of the ribs and diaphragm. Emphysemic patients have to make more of an effort to breathe out.
This takes a lot out of people and emphysema sufferers are weak, lack energy and usually lose a lot of weight. Although it can start simply as mild breathlessness during exercise and a persistent cough, it can leave sufferers housebound and reliant on oxygen supplies, and eventually cause their death.
What causes emphysema?
The main cause is smoking - 80 per cent of cases of emphysema occur in people who smoke. Emphysema usually affects older people as it is due to cumulative damage over a long period, such as a lifetime of smoking. Working in certain industries, such as mining, appears to increase the risk of developing emphysema.
It is common for smokers to get a combination of emphysema and chronic bronchitis, caused by the lungs' inability to clear mucus, which becomes infected. This combination is called chronic obstructive pulmonary disease (COPD). In COPD, surgeons have taken the radical step of giving lung transplants, and another technique called lung volume reduction surgery is used. This cuts away the most diseased parts of the lungs, meaning that the remaining lung will work more efficiently.
Currently, emphysema cannot be cured, although radical surgical methods have been tried with some success. Most patients try to control the symptons with bronchodilators - the same inhalers asthmatics use - as these help relax the airways and help oxygen get to the lungs. They can also do breathing exercises and try to improve their general fitness.
Alpha 1-antitrypsin deficiency (A1AD) is a genetic disorder that causes people to develop emphysema. People with the disease cannot make the protein alpha-1-antitrypsin, which is normally found in blood. This protein protects delicate tissues from damage – when it is not there, the alveoli in the lungs are particularly badly affected.
With no protection, the alveoli are more easily damaged by inhaling smoke and pollutants, and emphysema can develop in even quite young people. Fortunately, the disease can be treated by giving injections alpha-1-antitrypsin.
Finally, remember that emphysema is an example of a disease in which fibrosis occurs. Cystic fibrosis is another example. But what is fibrosis? Fibrosis is the formation of excess fibrous connective tissue occurring in an organ or a tissue after damage. It can occur in other organs as well as the lungs. It is a common feature of cirrhosis of the liver, for example, and of sickle cell anaemia, where fibrosis occurs in the spleen.
In the entire series of my posts on HEALTH AND DISEASES, I made mention the following and explain that:
- Diseases can be communicable, non-communicable or genetic. Communicable diseases are infectious: non-communicable diseases include degenerative diseases and lifestyle diseases; genetic diseases are inherited.
- Diagnosis is the process of working out which type of disease and which specific disease is causing a set of symptoms. Diagnosis uses many different techniques, including biochemical tests, imaging techniques, looking at cells and body fluids and looking for physical signs of illness.
- Infectious diseases are caused by microorganisms that invade the body - bacteria, viruses, parasites and fungi.
- The pathogens that cause infectious disease get into the body through the air, which is inhaled, through the digestive system, by sexual contact and through breaks in the skin.
- Infection can occur with and without disease. Many viral infections have an incubation period when the infection is there, and can be passed on, but there are no symptoms.
- Tuberculosis is caused by a bacterium. It affects millions of people globally each year and causes millions of deaths. Many strains of the bacteria that cause TB have become resistant to antibiotics.
- AIDS and influenza are examples of infectious diseases caused by viruses.
- Parasitic diseases can be caused by protoctists and parasitic worms. Parasites live on or in a host organism, gaining a nutritional advantage and causing the host harm.
- Malaria, an example of a parasitic disease, kills 1.5 million people each year worldwide. It is caused by a Plasmodium species and is transmitted to humans by the bite of the Anopheles mosquito.
- Lifestyle diseases include cardiovascular disease (often called heart disease), cancer and lung disease.
- Lifestyle diseases all have their own specific collection of risk factors.
- The main risk factors for heart disease include smoking, eating a diet high in fat and sugar but low in fibre and fresh fruit and vegetables, and not taking enough exercise. The main risk factors for cancer are smoking, some foods in the diet and some compounds in the environment.
- Major lifestyle diseases that affect the lungs are asthma, emphysema and fibrosis. Asthma usually develops as a result of a response to pollutants in the air. Emphysema is a lung condition that develops as a result of smoking or working in certain industries, such as mining. Fibrosis can result from lifestyle lung disorders or from genetic diseases such as cystic fibrosis.
Thanks for reading.