Identifying cancer early can positively impact the outcomes of treatment. Cancer screening tests are an important part of preventive care and there are multiple tests that can be used together or separately to screen for cancer. Which tests you may need to screen for cancer depends on your age and other factors.
Does a blood test show cancer?
Specific blood tests can screen for the presence of some cancers or indicate that cancer may be present, signaling that doctors should order more tests. Some blood tests include:
Complete blood count
When you undergo blood work, your doctor orders one or more tests that would be performed by a laboratory. A Complete Blood Count (or CBC) test is often ordered as a part of routine blood work. For this test, laboratory technicians use dyes to stain the platelets, red blood cells and white blood cells present in the sample. Then the sample is examined under a microscope to assess how many of each type of cell is present, the size of the cells and how mature they are.
A CBC test may help detect cancers of the blood, such as:
- Hodgkin lymphoma (cancer that begins in the lymph system)
- Leukemia (cancer of the blood that starts in bone marrow)
- Non-Hodgkin lymphoma (cancer that begins in the white blood cells)
- Multiple myeloma (cancer that starts in blood plasma)
CBC tests may also reveal other abnormalities that indicate you may need more testing. Doctors can also use this test to diagnose medical conditions other than cancer, like anemia.
Prostate-specific antigen test
The prostate-specific antigen, or PSA, test checks for levels of prostate-specific antigen protein present in a blood sample. Elevated PSA levels may be caused by cancerous cells in the prostate — or by healthy cells if the prostate is enlarged and inflamed. If your PSA test reveals abnormally high PSA levels, your doctor may order diagnostic tests to find out if prostate cancer is the cause.
Blood protein test
A blood protein test indicates whether certain proteins made by the immune system are present in your blood. The test is normally used to screen for multiple myeloma.
What other tests are done to screen for specific cancers?
Cancer screening may involve genetic testing, blood tests as described above, and specific screening tests for cancers of the breast, cervical, colorectal, prostate, lung and skin. Doctors determine which tests to order for cancer screening based on age, personal medical history, family medical history and other factors.
Breast cancer screening
Mammograms are the most common test used to detect breast cancer. They are imaging tests where the breast is held in place by two plates while pictures are taken with an X-ray machine to find tumors and other abnormalities.
Most women with an average risk for breast cancer are advised to begin getting screening mammograms at age 50.
Cervical cancer screening
Cervical cancer tests may include:
- Pap smears, where a doctor uses a tiny brush to collect cells from the cervix. The cells are then sent to a lab and checked under a microscope in search of abnormalities.
- HPV tests, which are often done at the same time as a pap smear, check for the presence of human papillomavirus. HPV can increase the risk of cervical cancer. If an HPV test is positive, doctors may recommend more frequent pap smears.
Most women at average risk are advised to undergo regular cervical cancer screening from age 21 to 65 at least every 3 years.
Colorectal cancer screening
Colorectal cancer screening tests may include:
- Colonoscopies and sigmoidoscopies, where doctors insert a thin lighted tube into the rectum through the anus to look for abnormalities in the colon
- High-sensitivity fecal occult blood tests, which check for hidden blood in stool samples that may indicate the presence of colon cancer
- Stool DNA tests, which look for mutations and changes in DNA that may indicate the presence of cancerous tumors or precancerous polyps
Most men and women at average risk are advised to begin getting screened for colorectal cancer between the ages of 45 and 50 until the age of 75.
Prostate cancer screening
Prostate cancer screening tests may include:
- PSA test to check for prostate cancer tumor markers
- Prostate MRI, an imaging test that uses magnetic and radio waves to take detailed pictures of the prostate
Lung cancer screening
Lung cancer screening typically involves taking images of the lungs. The medical imaging test most commonly performed for lung cancer screening is low-dose helical computed tomography. The test is a CT scan that involves taking pictures with an x-ray machine linked to a computer.
Current and former heavy smokers and anyone at an increased risk are advised to undergo regular lung cancer screening from age 50 to 80.
Skin cancer screening
Skin cancer screening tests may include:
- Self skin check, where you check your own body for growths, changes in moles and other abnormalities
- Clinical skin check, where a doctor examines your body looking for potential signs of cancer
- Skin cancer scan, which uses state-of-the-art technology to detect the presence of malignant moles
Genetic testing isn’t used to screen for active cancer. Instead, the information gathered through genetic testing can help assess your risk for developing cancer in the future. Studies indicate that variations in genetic code may account for 5 to 10% of all cancer. Genetic testing can reveal whether you have any of these variations present in your genetic makeup.
The presence of genetic variations doesn’t mean that you will definitely develop cancer in the future. Rather, they suggest that you’re at an increased risk. Genetic tests can determine if you should undergo more frequent cancer screening tests. A preventative care provider can also use the information to recommend lifestyle changes that you can make to potentially mitigate some of your risk for cancer.
What is the most common test for cancer?
The most common test for cancer is the biopsy. A biopsy is a procedure where cells, fluids, tissues, or growths are removed from the body and then examined under a microscope in a laboratory. Normally, a biopsy isn’t performed as a cancer screening test. Instead, doctors usually order a biopsy if cancer screening tests detect the presence of cancer. The results of the biopsy can help doctors determine if cancer is present and if so, provide a diagnosis.
In addition to a biopsy, your doctor may also order medical imaging tests if they believe you may have some type of cancer based on the findings of cancer screening tests or symptoms that you describe. Imaging tests for cancer detection and diagnosis include x-rays, MRIs and CT scans.
Blood tests for diagnosing and monitoring cancer
Some blood tests are useful tools for monitoring the effectiveness of cancer treatment. These include tumor marker tests and circulating tumor cell tests.
Tumor marker tests
Tumor marker tests search for substances that certain cancer cells produce. Because healthy cells may also manufacture the same substances, tumor marker tests are typically used to track how cancer is responding to treatment. Specifically, a decrease in tumor markers may indicate that the treatment is working. The PSA test is a rare example of a tumor marker test that doctors use as a cancer screening tool rather than for monitoring treatment progress.
Circulating tumor cells tests
Circulating tumor cells tests find tumor cells that are moving through the bloodstream. When tests locate these cells, the findings indicate that the cancer may be spreading to other areas of the body. Circulating tumor cell tests are a newer technology. Currently, there are tests available for a limited number of types of cancer, including prostate, colorectal and breast. In the future, doctors may likely be able to order circulating tumor tests for other types of cancer.
How Forward simplifies cancer screening
Through our doctor-led Cancer Prevention program, Forward simplifies cancer screening. The program begins with genetic testing and cancer screenings that incorporate state-of-the-art technology. Together, these tests can detect the presence of the five most commonly diagnosed cancers in the U.S.: lung, breast, colon, prostate and skin. In addition, they help assess your risk of developing these forms of cancers in the future.
Based on the findings of the comprehensive testing, Forward will develop a cancer prevention plan that incorporates lifestyle changes that you can make to help mitigate some of your risk. Our support doesn’t stop with the creation of the plan. We serve as your long-term doctor and act as your partner, giving you the support you need to make lasting positive change.