Prostate Cancer Tests

Prostate Cancer Tests
Content contributed by R. Alex Hsi, M.D.
Peninsula Cancer Center

Prostate Cancer Tests: Screening and Diagnosis

Prostate Cancer Tests

Diagnosis of prostate cancer should be part of a routine annual examination by your primary care doctor. The prostate cancer tests for early detection and screening are the Digital Rectal Exam, DRE, combined with a blood test to measure the Prostate Specific Antigen, PSA level, in the bloodstream. Abnormal DRE, elevated PSA or confirmation of more advanced Prostate Cancer will require additional testing, see table below.

Prostate Cancer Tests

Prostate Cancer Screen Test What is it? Why? Additional Information
DRE Digital Rectal Exam
Doctor inserts a gloved and lubricated finger into the rectum. Allows the doctor to feel the back portion of the prostate gland for size, and any irregular or firm areas. It is not accurate at detecting prostate cancer that is situated deep within the gland or is very small.
Prostate Specific Antigen (PSA)
Blood test to determine if PSA levels are within the normal range. Growth of prostate cancer cells as well as other conditions
(benign enlargement of the prostate (BPH) or inflammation/infection or prostatitis) can cause an elevation of the PSA level in the blood.
Men can be diagnosed with prostate cancer even with a PSA in the normal range. In one large study, about 15% of men diagnosed with prostate cancer did indeed have a PSA in the normal range. See below regarding the controversies surrounding PSA screening. Information on normal vs abnormal PSA Levels and PSA relation to Age can be found by selecting the PSA ICON at the bottom of the page.
Prostate Cancer Test after Failed Screen What is it? Why? Additional Information
Percent-Free PSA Ratio
Blood test that compares the amount of PSA bound to proteins in the blood to the amount of PSA that circulates by itself (unbound). When the percent-free PSA ratio is found to be 22% or less, prostate cancer is more likely to be present. This test can be useful when the standard PSA test is at or just over the high end of the normal range.
PCA3Plus®
Doctor performs a digital rectal exam and massages the prostate to induce the shedding of prostate cells into the urine. A urine sample is collected and sent to a laboratory to obtain a PCA3 score. Test detects a specific gene called PCA3, which is highly expressed in prostate cancer cells. The higher the score, the more likely a biopsy will be positive for prostate cancer.
Transrectal Ultrasound (TRUS)
A specific ultrasound test that uses a probe inserted into the rectum to visualize the prostate gland. Used to measure the size of the gland, detect anatomic variations and sometimes detect abnormal tissue. Needle biopsies of the prostate are usually done under TRUS guidance. Typically, a urologist performs these procedures in the office by placing the patient on his side and inserting the ultrasound probe into the rectum. Needles are pushed alongside the ultrasound probe through the rectal wall and into the prostate to sample the tissue. Usually 10-12 biopsies are taken covering the entire gland.
Prostate Biopsy
A prostate gland biopsy is a test to remove small samples of prostate tissue to be examined under a microscope. Needle biopsies of the prostate are usually done under TRUS guidance. Based on the above mentioned screening tests, a biopsy may be recommended. Urologist usually performs these procedures in the office. Usually 10-12 biopsies are taken covering the entire gland.
Prostate Cancer Test Intermediate to High Risk What is it? Why? Additional Information
Bone Scan
A nuclear medicine test in which a small amount of radioactive material called technetium-99m is injected into the blood. Test provides images of the bones which can show areas of increased uptake of the radioactive material suggesting the presence of cancer. The patient lies on a table that slides underneath a scanner which detects the radioactive material.
CAT Scan (Computerized Axial Tomography)
A detailed x-ray that can show both bones and soft tissue of the body Often used to look for enlarged lymph nodes in the pelvis which may indicate the spread of cancer outside of the prostate. The patient lies on a table which slides through a donut shaped scanner which directs x-rays through the body from many different angles. An iodine-based dye may be injected into a vein to help organs or tissues show up more clearly.
MRI Scan (Magnetic Resonance Imaging)
A MRI scan uses a very strong magnet, radio waves, and a computer to make very detailed images of areas inside the body. A device called an endorectal coil, which is placed inside the rectum just before the scan, can be used to give very detailed images of the prostate and the immediate surrounding tissue. Can be very helpful in determining if cancer has extended outside the prostate and into adjacent organs or tissues. Newer techniques such as diffusion weighting and dynamic contrast enhancement provide even more detail within and around the prostate. MRI images can be fused with real-time ultrasound images to more accurately direct biopsy needles at areas suspicious for cancer within the prostate. The patient lies on a table which slides through a tube shaped scanner which applies a magnetic field across the body. Newer techniques such as diffusion weighting and dynamic contrast enhancement provide even more detail within and around the prostate. These newer techniques are also being used to help improve the accuracy of prostate biopsies since prostate cancer is not well visualized within the prostate with ultrasound imaging.
Sodium Fluoride PET Scan
A nuclear medicine test similar to a bone scan (above) using a radioactive dye called 18F-sodium fluoride. Test can be used if findings on bone scan are negative, but there is still a high suspicion of spread of prostate cancer to the bones. The process for obtaining the test is similar to a bone scan, but this test more sensitive with shorter uptake and scan times.

Is Prostate Cancer Screening Necessary?

Prostate cancer screening has become controversial since a government committee, called the United States Preventative Task Force (USPSTF) recommended against routine PSA-based screening in 2012. This recommendation was based on a flawed study and there still remains much disagreement within the medical community regarding the merits of screening. Many professional medical societies, including the American Cancer Society and American Urologic Association still recommend some form of prostate cancer screening, although patients should discuss with their doctors the merits and drawbacks to screening.

American Cancer Society recommends annual screening for men whose PSA level is 2.5 ng/mL or higher.

Advice for Prostate Cancer Patients: Prostate Cancer Tests
Prostate Cancer Basics: Prostate Cancer Tests
Do You Have Prostate Cancer? What does PSA Mean?