Tests and diagnosisBy Mayo Clinic staff
Screening for prostate cancer
Whether to test healthy men with no prostate symptoms for prostate cancer is controversial. Medical organizations don't agree on the issue of screening and whether it has benefits. Some medical organizations recommend men consider prostate cancer screening in their 40s, or sooner for men who have risk factors for prostate cancer. Other organizations advise against screening. Discuss your particular situation and the benefits and risks of screening with your doctor. Together you can decide whether prostate cancer screening is appropriate for you.
Prostate screening tests might include:
- Digital rectal exam (DRE). During a DRE, your doctor inserts a gloved, lubricated finger into your rectum to examine your prostate, which is adjacent to the rectum. If your doctor finds any abnormalities in the texture, shape or size of your gland, you may need more tests.
- Prostate-specific antigen (PSA) test. A blood sample is drawn from a vein in your arm and analyzed for PSA, a substance that's naturally produced by your prostate gland. It's normal for a small amount of PSA to be in your bloodstream. However, if a higher than normal level is found, it may be an indication of prostate infection, inflammation, enlargement or cancer.
PSA testing combined with DRE helps identify prostate cancers at their earliest stages, but studies haven't proved that these tests save lives. For that reason, there is much debate surrounding prostate cancer screening.
Diagnosing prostate cancer
If an abnormality is detected on a DRE or PSA test, your doctor may recommend tests to determine whether you have prostate cancer, such as:
- Ultrasound. If other tests raise concerns, your doctor may use transrectal ultrasound to further evaluate your prostate. A small probe, about the size and shape of a cigar, is inserted into your rectum. The probe uses sound waves to make a picture of your prostate gland.
- Collecting a sample of prostate tissue. If initial test results suggest prostate cancer, your doctor may recommend a procedure to collect a sample of suspicious cells from your prostate (prostate biopsy). Prostate biopsy is often done using a thin needle that's inserted into the prostate to collect tissue. The tissue sample is analyzed in a laboratory to determine whether cancer cells are present.
Determining whether prostate cancer is aggressive
When a biopsy confirms the presence of cancer, the next step, called grading, is to determine how aggressive the cancer is. The tissue samples are studied, and the cancer cells are compared with healthy prostate cells. The more the cancer cells differ from the healthy cells, the more aggressive the cancer and the more likely it is to spread quickly. More-aggressive cancer cells have a higher grade.
The most common scale used to evaluate the grade of prostate cancer cells is called a Gleason score. Scoring combines two numbers and can range from 2 (nonaggressive cancer) to 10 (very aggressive cancer).
Determining how far the cancer has spread
Once a cancer diagnosis has been made, your doctor works to determine the extent (stage) of the cancer. Many men won't require these additional tests. But if your doctor suspects your cancer may have spread beyond your prostate, imaging tests such as these may be recommended:
- Bone scan
- Computerized tomography (CT) scan
- Magnetic resonance imaging (MRI)
Once testing is complete, your doctor assigns your cancer a stage. This helps determine your treatment options. The prostate cancer stages are:
- Stage I. This stage signifies very early cancer that's confined to a small area of the prostate. When viewed under a microscope, the cancer cells aren't considered aggressive.
- Stage II. Cancer at this stage may still be small, but may be considered aggressive when cancer cells are viewed under the microscope. Or cancer that is stage II may be larger and may have grown to involve both sides of the prostate gland.
- Stage III. The cancer has spread beyond the prostate to the seminal vesicles or other nearby tissues.
- Stage IV. The cancer has grown to invade nearby organs, such as the bladder, or spread to lymph nodes, bones, lungs or other organs.
- Nelson WG, et al. Prostate cancer. In: Abeloff MD, et al. Abeloff's Clinical Oncology. 4th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2008:1653.
- Prostate cancer. Fort Washington, Pa.: National Comprehensive Cancer Network. http://www.nccn.org/professionals/physician_gls/f_guidelines.asp. Accessed Jan. 9, 2012.
- What you need to know about prostate cancer. National Cancer Institute. http://www.cancer.gov/cancertopics/wyntk/prostate. Accessed Jan. 10, 2012.
- Abouassaly R, et al. Epidemiology, etiology and prevention of prostate cancer. In: Wein AJ, et al. Campbell-Walsh Urology. 10th ed. Philadelphia, Pa.: Saunders Elsevier; 2012. http://www.mdconsult.com/das/book/body/208746819-6/0/1445/0.html. Accessed Jan. 10, 2012.
- Prostate cancer early detection. Fort Washington, Pa.: National Comprehensive Cancer Network. http://www.nccn.org/professionals/physician_gls/f_guidelines.asp. Accessed Jan. 9, 2012.
- Prostate cancer prevention (PDQ). National Cancer Institute. http://www.cancer.gov/cancertopics/pdq/prevention/prostate/healthprofessional. Accessed Jan. 10, 2012.
- Catalona WJ, et al. Definitive therapy for localized prostate cancer: An overview. In: Wein AJ, et al. Campbell-Walsh Urology. 10th ed. Philadelphia, Pa.: Saunders Elsevier; 2012. http://www.mdconsult.com/das/book/body/208746819-6/0/1445/0.html. Accessed Jan. 16, 2012.
- McClure MW. Prostate cancer. In: Rakel D. Integrative Medicine. 2nd ed. Philadelphia, Pa.: Saunders Elsevier; 2007. http://www.mdconsult.com/das/book/body/178018505-4/0/1494/0.html. Accessed Jan. 10, 2012.
- Distress management. Fort Washington, Pa.: National Comprehensive Cancer Network. http://www.nccn.org/professionals/physician_gls/f_guidelines.asp. Accessed Jan. 10, 2012.
- Castle EP (expert opinion). Mayo Clinic, Phoenix/Scottsdale, Ariz. Jan. 25, 2012.
- Moynihan TJ (expert opinion). Mayo Clinic, Rochester, Minn. Jan. 27, 2012.