INTRODUCTION
Lung Cancer, growth of malignant cells affecting, initially, the lung. Cancer forms when a lung cell undergoes alterations to its DNA , leading to uncontrolled cell growth. Proliferation continues until a tumour forms. The process of metastasis (spread) takes place when cells break off from the tumour and travel via the blood or lymphatic system, lodging in other organs. There they begin to multiply, forming other tumours. Lung cancer falls into two groups: small cell and non-small cell carcinomas. Small cell lung cancer (SCLC) is also called oat cell carcinoma because of the cells’ shape. About 25 per cent of lung cancers are of this type.
Non-small cell lung cancer (non-SCLC) comprises squamous cell (or epidermoid) cancer, which arises from cells that line the airways of the lung, and is the most common form of lung cancer; Adenocarcinoma, which arises in mucus-producing cells which line the upper airways of the lung; and large cell carcinoma.
SYMPTOMS
The symptoms of lung cancer are a persistent hacking cough, blood in the sputum, wheezy breathing, pain in the shoulder or chest, neck or facial swelling, and recurring pneumonia or bronchitis.
CAUSES
A huge proportion—90 per cent—of lung cancers is caused by smoking. About 6 per cent may be linked to a naturally occurring radioactive gas, radon. Other causes are passive smoking (breathing in smoke from other people’s cigarettes, cigars, or pipes) and exposure to certain substances such as asbestos. Diet may also be involved; studies have shown that a diet low in fresh fruit and vegetables may increase risk.
TREATMENT
Lung cancer is difficult to control with existing treatments. Less than 10 per cent of patients survive for five years after diagnosis. This is mainly because the cancer has usually spread before it is diagnosed and surgery is therefore not an option. Radiotherapy and chemotherapy can help improve a patient’s quality of life and in some cases extend life.
Small cell lung cancer spreads rapidly and is sensitive to drugs, so chemotherapy can control it for a while. However, the cells may become drug resistant and therefore the periods of remission become shorter.
Surgery may be possible in patients with non-SCLC if the cancer is confined to the original tumour site and has not metastasized. Unfortunately, it is common for this type of cancer to return. Treatment for advanced cancer may include radiotherapy, chemotherapy, or laser therapy.
Senin, 23 Maret 2009
Sabtu, 21 Maret 2009
Bowel Cancer
Introduction
Bowel Cancer or Colorectal Cancer, a growth of malignant cells affecting, initially, the colon or rectum of the large intestine. Cancer starts when a bowel cell suffers alterations to its DNA (see Nucleic Acids), which cause it to abandon the normal controls on cell growth. The cells continue to proliferate until they form a polyp (a small tumour of the mucous membrane). Most polyps in other parts of the body are benign, but some occurring in the bowel may become cancerous.
SYMPTOMS
A change in bowel habit (especially constipation) is the most notable symptom, but watery diarrhoea is also possible. Rectal bleeding; pain; and tenesmus (a constant feeling of incomplete emptying of the rectum) are also possible symptoms.
DIAGNOSIS AND SCREENING
Bowel cancer is 90 per cent curable when diagnosed early and can be prevented by removing precancerous polyps. Unfortunately, most cases in the United Kingdom are not discovered early enough for a cure. Therefore, a suitable screening test has the potential to save many lives. The overall survival rate for bowel cancer in England and Wales is about 40 per cent.
One method is a test for blood in the stool called Haemoccult. However, it is not totally accurate, as it is only capable of finding 60 per cent of bowel cancers and 20 per cent of precancerous polyps. Researchers are investigating more accurate tests that detect DNA mutations in cells shed by the bowel lining into the stool.
Another way of screening uses a sigmoidoscope, an instrument that is inserted into the rectum to examine that part of the bowel and the sigmoid colon. Sigmoidoscopy usually finds benign polyps, and removing these growths almost halves a person’s cancer risk for ten years. A recent study showed that a once-only screening between the ages of 55 and 64 might prevent 5,500 cancers annually and 3,500 deaths in Britain. A large study is under way to evaluate this approach.
TREATMENT
The main treatment is surgery—removal of the tumour and, often, part of the bowel followed by resection. Nothing further is necessary provided the cancer has not spread beyond the bowel wall. Unfortunately, the prognosis is less favourable once the cancer has spread, as metastases tend to be resistant to chemotherapy and radiotherapy. However, there are numerous trials aimed at remedying this situation.
Bowel Cancer or Colorectal Cancer, a growth of malignant cells affecting, initially, the colon or rectum of the large intestine. Cancer starts when a bowel cell suffers alterations to its DNA (see Nucleic Acids), which cause it to abandon the normal controls on cell growth. The cells continue to proliferate until they form a polyp (a small tumour of the mucous membrane). Most polyps in other parts of the body are benign, but some occurring in the bowel may become cancerous.
SYMPTOMS
A change in bowel habit (especially constipation) is the most notable symptom, but watery diarrhoea is also possible. Rectal bleeding; pain; and tenesmus (a constant feeling of incomplete emptying of the rectum) are also possible symptoms.
DIAGNOSIS AND SCREENING
Bowel cancer is 90 per cent curable when diagnosed early and can be prevented by removing precancerous polyps. Unfortunately, most cases in the United Kingdom are not discovered early enough for a cure. Therefore, a suitable screening test has the potential to save many lives. The overall survival rate for bowel cancer in England and Wales is about 40 per cent.
One method is a test for blood in the stool called Haemoccult. However, it is not totally accurate, as it is only capable of finding 60 per cent of bowel cancers and 20 per cent of precancerous polyps. Researchers are investigating more accurate tests that detect DNA mutations in cells shed by the bowel lining into the stool.
Another way of screening uses a sigmoidoscope, an instrument that is inserted into the rectum to examine that part of the bowel and the sigmoid colon. Sigmoidoscopy usually finds benign polyps, and removing these growths almost halves a person’s cancer risk for ten years. A recent study showed that a once-only screening between the ages of 55 and 64 might prevent 5,500 cancers annually and 3,500 deaths in Britain. A large study is under way to evaluate this approach.
TREATMENT
The main treatment is surgery—removal of the tumour and, often, part of the bowel followed by resection. Nothing further is necessary provided the cancer has not spread beyond the bowel wall. Unfortunately, the prognosis is less favourable once the cancer has spread, as metastases tend to be resistant to chemotherapy and radiotherapy. However, there are numerous trials aimed at remedying this situation.
Jumat, 20 Maret 2009
Breast cancer
1. Introduction
Breast Cancer, growth of malignant cells affecting, initially, the breast.
As with other forms of cancer, it begins when the DNA in cells is altered, resulting in abnormal, uncontrolled cell growth. The cells continue to proliferate until they form a tumour. Breast cancer spreads when cells escape from the tumour and travel via the blood or lymphatic system to other parts and organs, such as the spine or lung, where they begin to multiply, forming other tumours, in the process known as metastasis.
2. Symptom
Breast cancer symptoms include an unusual lump, or change in the size or shape of the breast; puckering or dimpling of the skin of the breast; drawing back of the nipple; swelling of the upper arm, or in the armpit, or just above the breast; or pain or discomfort (although pain is only rarely a symptom of breast cancer). Only 1 in 40 women who reports any of these symptoms to a doctor is found to have cancer.
3. Treatment
A Early Breast Cancer
Breast conservation therapy is suitable for about 80 per cent of cancers and involves removing the lump (lumpectomy) and the lymph glands under the arm (the first site breast cancer spreads to), followed by radiotherapy. Research has shown that this newer method is as effective as mastectomy (surgical removal of the breast), which still tends to be the main treatment for early breast cancer.
Women may also be offered other treatments afterwards. Prescribing the hormone-blocking drug tamoxifen for post-menopausal women, and offering ovarian ablation (stopping the ovaries from producing oestrogen) to younger women would save 1,000 extra lives a year in the United Kingdom. Ovarian ablation can be done by removing the ovaries, irradiating them, or prescribing certain drugs.
B Advanced Breast Cancer
Treatment of advanced breast cancer, that is, cancer which has spread, is usually aimed at giving the patient a manageable quality of life with the disease kept under control, rather than a cure. Conventional treatments include drugs which cut oestrogen levels, and various chemotherapy combinations. Some women have bone metastases that cause pain and fractures. They may be treated with a new drug, APD, which helps to alleviate symptoms.
Breast Cancer, growth of malignant cells affecting, initially, the breast.
As with other forms of cancer, it begins when the DNA in cells is altered, resulting in abnormal, uncontrolled cell growth. The cells continue to proliferate until they form a tumour. Breast cancer spreads when cells escape from the tumour and travel via the blood or lymphatic system to other parts and organs, such as the spine or lung, where they begin to multiply, forming other tumours, in the process known as metastasis.
2. Symptom
Breast cancer symptoms include an unusual lump, or change in the size or shape of the breast; puckering or dimpling of the skin of the breast; drawing back of the nipple; swelling of the upper arm, or in the armpit, or just above the breast; or pain or discomfort (although pain is only rarely a symptom of breast cancer). Only 1 in 40 women who reports any of these symptoms to a doctor is found to have cancer.
3. Treatment
A Early Breast Cancer
Breast conservation therapy is suitable for about 80 per cent of cancers and involves removing the lump (lumpectomy) and the lymph glands under the arm (the first site breast cancer spreads to), followed by radiotherapy. Research has shown that this newer method is as effective as mastectomy (surgical removal of the breast), which still tends to be the main treatment for early breast cancer.
Women may also be offered other treatments afterwards. Prescribing the hormone-blocking drug tamoxifen for post-menopausal women, and offering ovarian ablation (stopping the ovaries from producing oestrogen) to younger women would save 1,000 extra lives a year in the United Kingdom. Ovarian ablation can be done by removing the ovaries, irradiating them, or prescribing certain drugs.
B Advanced Breast Cancer
Treatment of advanced breast cancer, that is, cancer which has spread, is usually aimed at giving the patient a manageable quality of life with the disease kept under control, rather than a cure. Conventional treatments include drugs which cut oestrogen levels, and various chemotherapy combinations. Some women have bone metastases that cause pain and fractures. They may be treated with a new drug, APD, which helps to alleviate symptoms.
Kamis, 19 Maret 2009
1. Introduction
Muscular Dystrophy, crippling disease characterized by gradual wasting of skeletal muscle. The clinical course is progressive, with increased weakness and diminution in muscle mass and function until the patient is confined to a wheelchair; remissions do not occur. Four clinical forms of the disease are recognized, based on pattern of inheritance, age when symptoms are first noted, and distribution of the muscles earliest involved. Microscopic abnormalities of skeletal muscle are found in each type.
2. Symptoms
In the Duchenne form of the disease, symptoms are usually noted before the age of five. The muscles first affected are those of the pelvis and trunk, resulting in spinal deformity and a waddling gait. Wasting of almost all muscle groups may be advanced by the late teens. Death may result from respiratory weakness or from involvement of the heart muscle. Because inheritance of this form is by an X-linked recessive mechanism, virtually all patients are boys. Becker muscular dystrophy is a milder form of Duchenne muscular dystrophy.
The facio-scapulo-humeral form of the disease affects both sexes equally and results in weakness and wasting of the shoulder girdle and upper arms. It is usually noted at around the onset of puberty. The characteristic weakness of the facial muscles may occasionally be seen during the first years of life. Most patients remain able to walk until an advanced age.
The limb-girdle type of the disease affects both sexes. Muscles of either the shoulder or hip girdle, or both, may be involved. The disease may begin early or late in life, and usually the course is slow. In the late stages most of the muscles of the body may be affected.
In myotonic muscular dystrophy, delayed relaxation of the muscles accompanies wasting and weakness. Cataracts of both eyes may occur, and reproductive functions may be disturbed. The age of onset and severity of symptoms are variable, but the disease tends to occur earlier and is more severe in later generations of an affected family. Myotonic muscular dystrophy affects both sexes, but children of affected mothers are more likely to inherit a severe form of the disease than children of affected fathers.
3. Treatment
Muscular dystrophy has its origin in a genetic mutation, but the biochemical steps by which this genetic defect manifests itself in the degenerative process in the muscle are not known. Because specific treatment is not available, general measures, including physical and occupational therapy, are used. Genetic tests for mutations in the different genes causing muscular dystrophy provide rapid and accurate diagnosis for patients. In the case of the X-linked Duchenne and Becker muscular dystrophies, these tests allow detection of female carriers of the disorders.
From : Encarta encyclopedia
Muscular Dystrophy, crippling disease characterized by gradual wasting of skeletal muscle. The clinical course is progressive, with increased weakness and diminution in muscle mass and function until the patient is confined to a wheelchair; remissions do not occur. Four clinical forms of the disease are recognized, based on pattern of inheritance, age when symptoms are first noted, and distribution of the muscles earliest involved. Microscopic abnormalities of skeletal muscle are found in each type.
2. Symptoms
In the Duchenne form of the disease, symptoms are usually noted before the age of five. The muscles first affected are those of the pelvis and trunk, resulting in spinal deformity and a waddling gait. Wasting of almost all muscle groups may be advanced by the late teens. Death may result from respiratory weakness or from involvement of the heart muscle. Because inheritance of this form is by an X-linked recessive mechanism, virtually all patients are boys. Becker muscular dystrophy is a milder form of Duchenne muscular dystrophy.
The facio-scapulo-humeral form of the disease affects both sexes equally and results in weakness and wasting of the shoulder girdle and upper arms. It is usually noted at around the onset of puberty. The characteristic weakness of the facial muscles may occasionally be seen during the first years of life. Most patients remain able to walk until an advanced age.
The limb-girdle type of the disease affects both sexes. Muscles of either the shoulder or hip girdle, or both, may be involved. The disease may begin early or late in life, and usually the course is slow. In the late stages most of the muscles of the body may be affected.
In myotonic muscular dystrophy, delayed relaxation of the muscles accompanies wasting and weakness. Cataracts of both eyes may occur, and reproductive functions may be disturbed. The age of onset and severity of symptoms are variable, but the disease tends to occur earlier and is more severe in later generations of an affected family. Myotonic muscular dystrophy affects both sexes, but children of affected mothers are more likely to inherit a severe form of the disease than children of affected fathers.
3. Treatment
Muscular dystrophy has its origin in a genetic mutation, but the biochemical steps by which this genetic defect manifests itself in the degenerative process in the muscle are not known. Because specific treatment is not available, general measures, including physical and occupational therapy, are used. Genetic tests for mutations in the different genes causing muscular dystrophy provide rapid and accurate diagnosis for patients. In the case of the X-linked Duchenne and Becker muscular dystrophies, these tests allow detection of female carriers of the disorders.
From : Encarta encyclopedia
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