Understanding your risk for cancer is important. People who have close relatives with cancer or close relatives who have died from cancer, especially at a younger age, may be at higher risk. For example, a woman whose mother or sister had breast cancer is twice as likely to develop breast cancer than a woman who does not have this same family history.

Early detection and screening

Cancer treatment is more likely to be successful when the cancer is diagnosed before it has spread. For many types of cancer, regular screening tests can help detect cancer early.

Currently, doctors can screen for cancers of the breast, colon, rectum, cervix, prostate, testes, mouth and mouth area, and skin. Screening tests for other cancers, such as lung and ovarian cancer, are currently being evaluated. Self-examination is also recommended for breast, skin, and testicular cancers, among others.

To determine which tests are most appropriate for each person, the doctor will consider a person's age, family history of cancer, ethnicity, and lifestyle. People at high risk for developing cancer should talk with their doctor about starting regular screening.

Tests to diagnose cancer

Doctors use many different types of tests to diagnose cancer and to find out how far the disease has spread. Some tests can also determine which treatments will work best for a particular person. Diagnostic tests can involve simple laboratory tests, surgery, or radiologic imaging. The tests a doctor selects depends on the type of cancer that is suspected; the person's symptoms, age, and medical condition; and the results of other tests.

Biopsy.

In many cases, a diagnosis of cancer is made with a biopsy. This test involves the doctor removing all or part of the tumor and then examining the sample under the microscope to determine if cancer cells are present. There are different kinds of biopsies.

Surgical biopsy. The doctor removes part of the lump (incisional biopsy) or the entire tumor or organ (excisional biopsy).

Fine needle biopsy. The doctor numbs the skin and removes a small sample of tissue with a thin needle.

Bone marrow biopsy. The doctor removes a sample of bone marrow, usually from the back of the hip, with a syringe.

Imaging tests

Doctors use imaging tests to determine whether the cancer has spread to other areas in the body, and to evaluate the size and location of the tumor. Imaging tests alone are generally not specific enough to diagnose cancer.

X-ray. X-rays use electromagnetic radiation to produce an image of the inside of the body. X-rays are not as sophisticated as newer procedures, but they are still useful for finding and monitoring some types of tumors.

Computerized tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the inside of the body using a series of x-ray pictures that are taken from many different angles. A computer compiles these images into a detailed, cross-sectional view.

Magnetic resonance imaging (MRI). An MRI uses electromagnetic waves to create computer-generated pictures of the inside of the body.

Ultrasound. Ultrasounds create pictures of the inside of body using high-frequency sound waves.

Positron emission tomography (PET) scan. This is a procedure in which radioactive sugar molecules, called tracers, are injected into the body in a low dose, radioactive form. During the scan, the cancer cells "light up," because the cancer cells absorb sugar faster than normal cells.

Bone scan. This test is used to determine if the bone is damaged, either from cancer or from some other cause. A radioactive tracer is injected into a person's body. If the bone is damaged, the tracer will concentrate in the bone.

Endoscopic tests

Laboratory tests

Laboratory tests involve testing a sample of blood, urine, and other body fluids to learn or confirm what is happening in the body. One of the most common tests is a complete blood count (CBC). A CBC measures the components of the blood, including white blood cells, red blood cells, and platelets. Blood tests are also used to monitor potential side effects of cancer treatment, such as anemia or infection.

Specific laboratory tests help doctors make treatment decisions. For example, the breast cells of women with breast cancer may be tested to determine whether the cells have the estrogen receptor, which lets doctors know whether these women will respond to hormone-based treatment. Also, the breast cancer drug trastuzumab (Herceptin) is only effective in people whose breast cells have a particular protein called HER2/neu. Some tests can be used to determine whether the cancer has returned, although this use differs for each cancer.

Types of Cancer