Cancer
Cancer is a disease in which a group of cells divides abnormally without any control, so as to overrun and even destroy other tissues. These cells spread all over the body through the blood and lymph, giving rise to satellite lesions elsewhere and then eventually leading to death. The main types of cancer are sarcoma, carcinoma, lymphoma and myeloma, leukemia, and central nervous system cancers. The name of a cancer varies depending upon the organ involved or the type of cell from which the cancer has arisen. Thus, a cancer that starts off in the prostate is a prostatic cancer, whereas another one involving the liver cells is called a hepatocellular cancer. Further, depending on whether the cancer has been derived from mesenchymal tissue or epithelial tissue, it is referred to as a sarcoma or a carcinoma, respectively.
Sarcomas basically develop from muscle tissue, blood vessels, cartilage, fat, bone, or any other connective or supportive tissues. Carcinomas arise from the skin or tissues, which cover the internal organs. Lymphomas and Myelomas are cancers involving cells of the immune system. Leukemia starts off in the bone marrow, producing numerous abnormal blood cells that then enter the blood stream and infiltrate various tissues and organs. Cancers of the central nervous system develop in the spinal cord or brain.
Cancers have their origin within the cells themselves, the basic units of the human body. Normally, the body cells multiply within physiological limits to keep the body healthy. As the cells age, they are regularly destroyed and replaced by new cells. However, a mutation may occur in the DNA of the cells that can affect cellular division and growth. The formation of new but abnormal cells goes on uncontrolled. As a result, these extra cells produce a mass of tissues known as a tumor. In leukemia, no tumor is formed as the blood cells are affected.
There are two types of tumors – Benign and Malignant. Benign tumors are not cancerous. The cells from these tumors do not spread to cause similar growths elsewhere in the body. They can be removed surgically and often do not recur. Malignant tumors are cancerous tumors, i.e., they are capable of spreading to other parts of body. This process is medically termed as metastasis. A cancerous tumor may or may not have a capsule. Those with a capsule tend to spread slower as compared to those without a capsule. Also, the capsulated ones are more amenable to surgical removal, rather than the ones that encroach upon the adjacent structures, acting like parasites by competing for nutrition and depriving the healthy tissues of their nourishment.
Carcinogens are external factors that can cause cancer. Some of the common ones are tobacco, infectious organisms, radiations, and chemicals. The internal factors that could trigger malignancies are hormonal disturbances, inherited gene mutations known as oncogenes, immunological disorders, and cellular changes brought about by altered metabolism. It should be noted that even if one is exposed to any of these factors, the development and progress of the disease is usually silent. Years may pass till a cancer starts manifesting itself in the form of signs and symptoms. This is why regular screening of people who are at risk of developing cancer is very important.
Cancer can manifest in many ways. Some of its symptoms include unexplained weight loss, chronic cough with hoarseness not responding to treatment, a long-standing non-healing sore, a lump in the breast or any abnormal growth elsewhere in the body, altered bowel or bladder habits, chronic dyspepsia with difficulty in swallowing, changes in the appearance of a wart or nevus, and abnormal discharges or bleeding. Since these symptoms could be due to various other diseases too, it is always better to get investigated to know the underlying cause.
Cancer treatment varies depending upon the type of cancer, its location, size, and spread. Often, a patient with cancer has to be treated by a team of specialists who coordinate with each other to maximize patient benefit and in order to try to decrease the possibility of complications. Surgical interventions, chemotherapy, radiation therapy, and hormonal or biological therapies are generally used alone or in combinations in the treatment of cancer. As of now, the success of any cancer treatment is assessed in terms of a five year relative survival rate.
Tobacco abuse in any form has been found to be responsible for cancer in many cases. In fact, according to statistics, nearly a third of all the cancer deaths in the world are associated with tobacco use. Certain studies have suggested a link between high-fat diet and some types of cancer. Others have found that foods rich in fiber and specific nutrients such as antioxidants may protect against some cancers. Non-vegetarians seem to be at a higher risk of developing gastrointestinal cancers as compared to vegetarians. Alcoholics have also been found to be at a higher risk of developing gastrointestinal cancers. Hence, limiting one’s consumption of these items is recommended.
The ultraviolet radiations of the sun or from artificial sources of light can lead to skin cancers. Hence, the use of sunscreens is recommended to protect the skin. Ionizing radiations from X-ray procedures, radioactive substances, and the rays that enter our planet’s atmosphere from outer space can cause cancer. Keeping this in mind, unnecessary or repetitive X-rays should be avoided as far as possible. Certain metals and chemicals such as asbestos, benzene, benzidene, cadmium, nickel, radon, uranium, and vinyl chloride, are capable of causing cancer. Some hormonal preparations used in hormonal replacement therapy or to treat conditions due to hormonal disturbances are known to trigger some forms of cancer too. Therefore, one needs to weigh the pros against the cons before administering them. Cancers associated with infectious agents like human papilloma virus (HPV), hepatitis B virus (HBV), human immunodeficiency virus (HIV), and others can be prevented by protecting oneself against these infections.
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