Cancer is a term for a large group of diseases that can affect any part of the body. There is rapid multiplication of abnormal cells that grow beyond their usual boundaries invading adjoining parts of the body and spread to other organs by the process of metastasis.
Cancer is a leading cause of death worldwide. The disease accounted for 7.4 million deaths (or around 13% of all deaths worldwide) in 2004. The main types of cancer leading to overall cancer mortality each year are:
More than 70% of all cancer deaths occurred in low- and middle-income countries. Deaths from cancer worldwide are projected to continue rising, with an estimated 12 million deaths in 2030.
The most frequent types of cancer worldwide (in order of the number of global deaths) are:
Cancer is a disease of uncontrolled and chaotic cell growth, damage to healthy tissues, and the ability to metastasize through blood and lymphatics.
The body is made up of many types of cells. Normally, cells grow and divide to produce more cells as they are needed to keep the body healthy. Sometimes, this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. This results in a mass of tissue called a tumor. Not all tumors are cancerous; they may be benign or malignant.
A benign tumor is encased in a membrane that keeps it from getting to other body tissues. Benign tumors are not considered to be cancerous but can cause damage to healthy tissues when the mass is large enough to compress them. A malignant tumor is much more dangerous and harmful than a benign tumor. A malignant tumor is cancerous because the cells are not encased in a membrane and can invade and destroy nearby tissues.
Cancerous cells can travel throughout the body via the circulatory system or the lymphatic system causing secondary cancers. The cancer is said to metastasize when this happens.
Cancer is caused by changes in genes that normally control the growth and death of cells. These changes may be brought about by certain lifestyle and environmental factors ,use of tobacco, diet, exposure to ultraviolet (UV) radiations, exposure to carcinogens (cancer-causing substances) in the workplace or in the environment and infection with certain viruses, such as the human papillomavirus (HPV), hepatitis B and C (HepB and HepC), and human immunodeficiency virus, (HIV).Some gene alterations are inherited.However, having an inherited gene alteration does not always mean that the person will develop cancer; it only means that the chance of getting cancer is increased.
Cancer can cause a variety of symptoms which include the following:
It is important to see a doctor about any of these symptoms or about other physical change. A person with these or other symptoms should not wait to feel pain because early cancer usually does not cause pain.
Cancer treatment can include surgery, radiation therapy, chemotherapy, hormone therapy, and biological therapy. The doctor may use one method or a combination of methods, depending on the type and location of the cancer, whether the disease has spread, the patient's age and general health, and other factors.
Surgery removes a cancer. The side effects of surgery depend on many factors, including the size and location of the tumor, the type of operation, and the patient's general health.
Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells in a targeted area. Radiation can be given externally by a machine that aims radiation at the tumor area. It can also be given internally; needles, seeds, wires, or catheters containing a radioactive substance are placed directly in or near the tumor. Radiation treatments are painless. The side effects are usually temporary, and most can be treated or controlled.
Chemotherapy is the use of drugs that kill cancer cells throughout the body. Healthy cells can also be harmed, especially those that divide quickly. The doctor may use one drug or a combination of drugs. The side effects of chemotherapy depend mainly on the drug(s) and the dose(s) the patient receives.
Hormone therapy is used to treat certain cancers that depend on hormones for their growth. It works by keeping cancer cells from getting or using the hormones they need to grow.Patients may feel tired, or have fluid retention, weight gain, hot flashes, nausea and vomiting, changes in appetite, and, in some cases, blood clots. Hormone therapy may also cause bone loss in premenopausal women.
Biological therapy uses the body's immune system, directly or indirectly, to fight disease and to lessen some of the side effects of cancer treatment. Monoclonal antibodies, interferon, interleukin-2, and colony-stimulating factors are some types of biological therapy.
Although there is no guaranteed way to prevent cancer, people can reduce their risk of developing cancer by:
Although many risk factors can be avoided, some, such as inherited conditions, are unavoidable. People who have an increased likelihood of developing cancer can help protect themselves by avoiding risk factors and by getting regular checkups so that, if cancer develops, it is likely to be found and treated early. Screening exams, such as sigmoidoscopyor the fecal occult blood test, mammography, and the Pap test, can detect precancerous conditions and early-stage cancer.
Yes, Cancer can be cured if detected early and treated promptly. Unfortunately in India, about 70% patients present in advanced stage diseases, which have poor chances of survival.
Cancer is a non-communicable disease, which does not spread from one person to another. Some cancers may have a hereditary link which means a person may be at higher risk of getting cancer if his/ her relatives have had that particular cancer. These cancers are breast, ovarian, colorectal, and other less common cancers.