Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems.
Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start – for example, cancer that begins in the colon is called colon cancer; cancer that begins in melanocytes of the skin is called melanoma.
Cancer types can be grouped into broader categories. The main categories of cancer include:
- Carcinoma – cancer that begins in the skin or in tissues that line or cover internal organs. There are a number of subtypes of carcinoma, including adenocarcinoma, basal cell carcinoma,squamous cell carcinoma, and transitional cell carcinoma.
- Sarcoma – cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
- Leukemia – cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.
- Lymphoma and myeloma – cancers that begin in the cells of the immune system.
- Central nervous system cancers – cancers that begin in the tissues of the brain and spinal cord.
Screening is looking for cancer before a person has any symptoms. In many cases, screening tests can identify cancer at an early stage when it is more treatable. If the cancer is not identified until symptoms develop it may have begun to spread throughout the body and become harder to treat.
There are many types of screening tests and everyone is recommended to have some type of cancer screening depending on many factors including age and sex or personal and family history factors. It is important to remember that if your physician recommends a screening test it does not necessarily mean he or she thinks you have cancer.
A few examples of screening tests include the following:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
- Laboratory tests: Medical procedures that test samples of tissue, blood, urine, or other substances in the body.
- Imaging procedures: Procedures that make pictures of areas inside the body.
- Genetic tests: Tests that look for certain gene mutations (changes) that are linked to some types of cancer.
There are risks to having a screening test. It is important to talk with your physician about the risks and benefits of a particular screening test and if it is appropriate for you.
Patients diagnosed with cancer have a number of treatment choices to make. These choices will depend on the type of cancer, the stage of the cancer, along with factors such as your age, health status, and personal desires. Many people feel that they must rush into treatment in order to take care of the cancer as fast as possible, but most patients have plenty of time to educate themselves and make sure the decision they make is the right one for them.
Because of the complexity of cancer, more than one type of treatment may be required to control or cure your cancer. Each treatment option has different benefits and side effects. This section of our website provides an overview of the treatments that may be considered for you. Your physician can help you understand your options and provide resources for additional education and support. You can also visit www.cancer.org for additional treatment information.