How do doctors diagnose cancer?
Doctors may suspect you have cancer based on:
A physical exam
Results from cancer screening tests (tests to look for cancer before you have symptoms)
To know for sure, doctors will do tests. They will diagnose (identify) your cancer using the test results.
Doctors will also do tests to see the stage of your cancer (stage I, stage II, stage III, or stage IV). Stages describe how big your cancer is and whether it has spread to other places in your body.
What tests can screen for cancer?
Screening tests are those your doctor does when you don't have any symptoms. Your doctor might suggest screening tests if you have a higher risk of having cancer based on your age, sex, family history, health, or lifestyle.
Doctors use different screening tests for different cancers. Some screening tests can help save lives, but only certain screening tests are reliable.
Some common screening tests include:
A mammogram Mammography Breast cancer occurs when cells in the breast become abnormal and divide uncontrollably. Breast cancer usually starts in the glands that produce milk (lobules) or the tubes (ducts) that carry... read more (x-ray of your breast) for breast cancer Breast Cancer Cancer is when cells grow abnormally. Cancer cells don't look or work like normal cells and keep multiplying out of control. Cancer cells can invade and destroy nearby healthy tissue. Sometimes... read more
PSA test Screening Prostate cancer begins in a small area of the prostate gland, an organ found only in males. The risk of prostate cancer increases as men age. Symptoms, such as difficulty urinating, a need to... read more (prostate specific antigen) for prostate cancer Prostate Cancer Cancer is the out-of-control growth of cells in your body. Cells are the tiny building blocks of your body. Cells specialize in what they do. Different organs are made of different kinds of... read more
Tests of your stool (poop) or a colonoscopy Endoscopy Endoscope is an instrument doctors use to look inside your body. Endoscopes can also be used to do tests and treat diseases. Endoscopes are tubes that have a light and a small video camera on... read more for colon cancer Colon Cancer Your colon is your large intestine. Your rectum is a pouch at the end of your colon where stool is stored until you pass it. Cancer is the out-of-control growth of cells in your body. Cells... read more
Doctors can do screening tests:
As part of your routine physical exam
At an office visit
During a procedure that has to be scheduled ahead of time
Even if a screening test is positive, doctors usually can’t tell for sure if you have cancer. Doctors will do more specific tests to know whether you have cancer.
What tests can diagnose cancer?
If doctors suspect cancer, they’ll usually do a test to take a picture of the inside of your body, such as an x-ray, ultrasound, or CT (computed tomography) or MRI (magnetic resonance imaging) scan. To tell for sure, doctors will do:
A biopsy (take a sample of your tissue) and look at the sample under a microscope
When doctors diagnose your cancer, they’ll do tests to find out the stage. The stage tells them where and how large the cancer is. The stage also tells if the cancer has grown and spread into other parts of your body. Knowing the stage helps doctors decide the best treatment. Staging tests include:
Biopsy from your tumor or tissues around your tumor
Blood tests to see if your liver, bones, and kidneys are working normally