Cancer occurs when the cells in the body grow out of control. Healthy cells divide and grow in an organized manner. Cancer cells, on the other hand, continue to divide until they form a large mass called a tumor. This uncontrollable cell division occurs when a cell's DNA, which directs all of the cell’s activities, sustains unrepaired damage.There are many different types of cancer, which typically begins in one part of the body, such as an organ (e.g., prostate) or tissue (e.g., breast). If the disease is not detected and treated in its early stages, it can spread (metastasize) to other tissues and organs in the body. According to the American Cancer Society (ACS), cancer will affect about one out of every two men and one out of every three women in the United States at some point in their lives.Though scientists do not understand exactly why DNA sustains damage, various factors have been identified that can increase an individual’s likelihood of developing cancer. These are called risk factors. Individuals who are aware of the risk factors associated with cancer can often prevent the disease by exercising certain cautionary measures, such as avoiding known carcinogens (cancer-causing agents).Several elements can be examined to help identify a person’s risk of cancer. It is important to note that such measures do not mean an individual will develop cancer, only that there is greater susceptibility. Knowing the information can allow individuals to take preventive measures and be monitored by a physician. These factors include:An individual’s medical history. For example, hepatitis or cirrhosis may lead to liver cancer. Dialysis increases the risk of kidney cancer. Having an undescended testicle (cryptorchidism) raises a man’s chance of getting testicular cancer.Family history of hereditary cancer or syndromes. Certain cancers have stronger genetic links than others. Women who have a mother, sister or daughter with breast cancer have a greater risk for developing the disease. Also, certain syndromes can increase a person’s risk, such as familial adenomatous polyposis (FAP). Individuals with this condition are prone to colorectal cancer.Genetic testing. For example, having mutations of BRCA genes increases the risk of breast cancer in women and prostate cancer in men.Preventive measures recommended by a physician depend on how much of an increased risk exists. For example, without treatment, people with FAP almost always develop colorectal cancer by age 40. Many of them undergo preventive removal of the colon (colectomy) to minimize this risk. Some women at high risk of breast cancer choose to have prophylactic mastectomy. In addition, women with breast cancer may be at increased risk to develop ovarian cancer. Breast cancer patients may choose to have their ovaries removed (oophorectomy) to prevent development of cancer there.A physician may recommend increased monitoring rather than preventive treatments for people who face only a moderately increased risk of cancer. For example, a man susceptible to prostate cancer could undergo increased screenings with the digital rectal exam and blood test for the tumor marker prostate-specific antigen. A woman susceptible to breast cancer could undergo mammograms with increased frequency at an earlier age or with increased frequency. The methods to monitor at-risk individuals for cancer are best determined by the patient’s physicians.
Malignant Mesiothelioma
Mesothelioma is a rare cancer. It is more common in men, which is due in most part to work-related exposure to asbestos. Risk also increases with age. The biggest risk factor for developing the disease is exposure to asbestos, accounting for 70 to 80 percent of all cases. Asbestos has been used in many products, including cement, brake linings, roof shingles, flooring products, textiles, and insulation. Particles can be released from these products, particularly during the manufacturing process, and inhaled. Prior to knowing the dangers, asbestos miners and other workers exposed to asbestos worked without wearing any protection. Smoking does not seem to increase the risk of developing the disease.
Signs
The symptoms of mesothelioma are caused by a build-up of tumor tissue surrounding the lung and fluid in the pleural space that prevents the lung from expanding fully. This causes pressure on the lung, leading to pain and shortness of breath. As the disease progresses, patients may lose weight and have a dry, hacking cough. In the abdomen, this fluid and tumor tissue causes abdominal swelling, pain and weight loss.
Diagnosis
Patients who present with symptoms worrisome for mesothelioma may have a chest x-ray done, indicating a build-up of fluid in the lining of the lung. These patients would then undergo CT scan to further evaluate the cancer. In the case of abdominal mesothelioma, a CT scan . Advance tests include a PET-CT SCAN which would indicate the presence of active disease. Patients would then undergo a biopsy to have the diagnosis confirmed. In the lung, a thoracoscope is used to go through the chest wall, between the ribs to obtain a sample of the tissue. A peritoneoscope is used to enter the abdomen to obtain a tissue sample in abdominal mesothelioma. Staging refers to determining the extent of the disease and this dictates the treatment. Physicians use the TNM system (also called tumor - node - metastasis system). This describes the size of the tumor (T), if the lymph nodes are involved (N), and if it has spread to other areas of the body (M). This is then interpreted to a stage between one and four. Patients with earlier stage tumors tend to live longer and respond better to available treatments.
Cancer Causes
Diet and lifestyle
There are over 200 different types of cancer. We don't know the causes for each one of these cancers, but we do know about some. It is important to note that for many cancers, there may be more than one cause.
One of the biggest risks is increasing age. Cancer can occur at any age but the risk of developing it increases with age. Nearly two thirds (64%) of people who get cancer are over the age of 65, and more than a third are over 75.
We make lifestyle choices everyday - some we know increase our risk of developing cancer, others may have an influence on our risk. For example, smoking is a major cause of lung cancer and is a factor in other cancers, such as bladder cancer and cancers of the head and neck. Other factors that can influence our risk of developing cancer include heavy alcohol consumption and exposure to sunlight.
It is also thought that diet can influence the development of some cancers, although the evidence is less clear. Diets high in animal fats have been linked with breast cancer, bowel cancer and prostate cancer. A diet that is low in fresh fruit and vegetables may also increase your risk of developing some types of cancer. Obesity has been linked to some cancers, such as cancer of the breast or kidney.
Environmental and occupational causes
Contact with certain harmful substances in the environment or workplace can cause cancer. Substances that are known to cause cancer are called carcinogens.
We know, for example, that 9 out of 10 people who develop mesothelioma (a rare type of cancer affecting the linings of the lung and abdomen) have had contact with asbestos. People who have worked in industries such as ship-building and construction may have come into contact with asbestos. Its use is now banned in the UK.
Certain chemicals used in dye factories, rubber production, gas works and other chemical industries have all been linked to bladder cancer. Fortunately these chemicals have now been banned.
Environmental causes include natural radiation, for example, from the sun. We know that most skin cancers, including melanoma, are caused because of prolonged exposure to the sun. Naturally occurring radon gas has also been linked to some types of cancer, namely lung cancer.
Viruses
It is important to remember cancers are not infectious and cannot be caught from someone. However, there are a number of different viruses that are thought to be contributing factors in the development of cancer.
For example, exposure to HPV (human papilloma virus) is known to increase the risk of developing some types of cancer. For further information about this, see the section about HPV.
Other viruses include the Epstein-Barr virus, which is linked to some types of lymphoma.
There is also a bacterial infection known as H-pylori which is linked to a rare type of stomach cancer.
