Cancer is the uncontrolled growth of abnormal cells that can destroy tissue and spread to other areas of the body. The disease can be found in many types of organs, such as the lungs, breasts, or brain. Cancer can be caused by genetic changes, or by certain lifestyle factors such as smoking, overexposure to the sun, or being overweight. The most common treatments are surgery, radiation and chemotherapy. A variety of other treatments are also available.
Treatments can shrink or kill cancerous cells and prevent them from spreading. They can also relieve symptoms, such as pain or shortness of breath, from the cancer itself or the effects of treatment. Some treatments use heat, radiation or drugs to kill cancer cells; others block the body’s hormones, such as estrogen in breast and ovarian cancers, or use hormones to slow tumor growth, such as in prostate cancer. The type of treatment recommended will depend on the type and stage of the cancer, as well as your general health and preferences.
The first step in preventing cancer is to make healthy choices in your diet and lifestyle. Smoking, drinking more than one alcoholic beverage per day and being overweight are all known to increase your risk of developing cancer.
When a person is born, their genes contain instructions that control how cells grow and die. These genes are passed from parent to child. Some gene mutations lead to faulty instructions that cause cancer. Other mutations occur after birth, and may be caused by chemicals or other environmental factors. The number of gene mutations that need to accumulate to develop cancer varies by type of cancer.
There are more than 100 different types of cancer. Each type develops when normal control mechanisms stop working and cells start to grow out of control, forming a mass of abnormal cells called a tumor. Some abnormal cells develop into carcinomas, which are the most common forms of cancer. Others develop into sarcomas, leukemias or melanomas.
Scientists have learned a lot about how cancer develops and grows over time. They have discovered that cancer cells are able to:
Ignore signals that normally tell cells to stop growing or to die (a process called programmed cell death). invade other tissues in the body. evade the immune system by hiding from it or tricking it into protecting them. rely on different kinds of nutrients than normal cells, and grow more quickly than normal cells.
Some types of cancer are easier to treat than others, but it’s important to understand all the options available to you and work with your doctor to determine which is best for you. Whether or not a cure is possible, many treatments can ease your symptoms and prolong life.