Cancer is a disease that develops when cells in your body grow and divide without control or order. The growth of these abnormal cells forms a mass called a tumor. Cancer can occur anywhere in your body. The term cancer can refer to any type of tissue cell that has mutated and continues to grow, such as skin cells, blood cells, nerve cells or intestinal cells. Cancer cells can also spread to other parts of the body through the blood or lymphatic systems. These new areas of cancer are called metastases.
Scientists are constantly working to find ways to improve treatment and prevent cancer. They are developing and testing a range of newer methods such as personalized medicine and gene therapy, which may lead to more effective treatments for people with cancer. In addition, there are many options for prevention — early detection through screening tests and taking steps to avoid certain risk factors — that can help reduce the number of cases of cancer in our country and around the world.
Normally, when cells in your body are damaged or change, they die and are replaced by healthy, normal cells. But sometimes, changes (mutations) in DNA cause cells to grow and multiply when they shouldn’t. Most of the time, the mutated cells are removed from the body through the stool or urine, but sometimes they escape into the bloodstream and travel to other parts of the body where they may start growing and forming a tumor. The abnormal cancer cells can also grow and invade healthy tissues, which causes the body’s natural defenses to fail.
The most common cancers are breast, lung and colon cancer. These types of cancer are usually caused by lifestyle and environmental risk factors, such as cigarette smoking, an unhealthy diet, excessive sun exposure and a lack of physical activity. The disease is less common in children and young adults, but it can strike at any age.
Most cancers develop due to a combination of genetic and environmental factors, but researchers are working hard to figure out exactly what causes them so that we can do more to prevent them. Some cancers are linked to infection with certain viruses and bacteria, such as human papilloma virus (HPV), Epstein-Barr virus (EBV), herpes simplex virus (HSV), hepatitis B and C viruses and the bacterium Helicobacter pylori.
Some cancers are treated with chemotherapy drugs, which kill cancer cells. This type of treatment can be given through a vein (intravenously, or IV), as an injection (shot) or in pill form to be swallowed or applied topically. Chemotherapy can be used before other cancer treatments or to prevent the return of the cancer after these treatments. It is important to learn everything you can about your chemotherapy treatment so you will know what to expect. This includes knowing how long each treatment will take and what side effects you might experience. Your oncologist can help you prepare for your treatment by explaining how the chemotherapy drug treatments work and what they are targeting.