April 22, 2014
- National Cancer Institute
- American Cancer Society
- American Society of Clinical Oncology
- Prostate Cancer Foundation
- Urology Health
- National Comprehensive Cancer Network
- CDC Cancer Prevention and Control
- PSA Rising: Prostate Cancer Survivor Info
- Us Too! Prostate Cancer Education and Support
- Find clinical trials
- Zero — The Project to End Prostate Cancer
There is great uncertainty and controversy over whether the benefits of regular screening for prostate cancer outweigh the risks for most men. Prostate cancer is often slow growing. Doctors cannot yet determine which early-stage tumors pose a risk of being aggressive and need treatment, and which tumors should be left alone. The concern is that routine screening for early detection of tumors may lead to invasive and unnecessary treatment.
In general, the current consensus is that there is no “one size fits all” guideline for who should receive prostate cancer screening and at what age. Before deciding to be tested, men need to discuss the pros and cons of screening with their doctors.
Candidates for Annual Screening. The best age to start annual screening is under debate. Major medical organizations generally recommend that:
- Men ages 50 - 75 should be offered annual screening with the PSA test and digital rectal exam. However, the United States Preventive Services Task Force notes that there is insufficient evidence to determine whether routine prostate cancer screening has benefits. If a man chooses to be tested, or would like the doctor to make the decision, he should be screened yearly with a PSA test and digital rectal exam.
- Men with a family history of prostate cancer and all African-American men should consider annual screening at about age 40 - 45.
- PSA testing is not recommended for men over age 75. Because of shortened lifespan, responding to abnormal PSA results in this age group may lead to overly aggressive treatment.
Standard Screening Tests for Early Detection
Two standard tests are used for early detection of prostate cancer:
- PSA test . The PSA blood test measures the level of a protein called prostate-specific antigen. It is able to detect early prostate cancer, although it has limitations.
- Digital rectal examination (DRE) . The DRE is a physical examination. The doctor inserts a gloved and lubricated finger into the patient's rectum and feels the prostate for bumps or other abnormalities.
PSA Test Limitations . Prostate specific antigen (PSA) is a protein produced in the prostate gland that keeps semen in liquid form. Prostate cancer cells appear to produce this protein in elevated quantities. Measuring PSA levels increases the chance for detecting the presence of cancer when it is microscopic. There are many unresolved questions surrounding PSA testing. The test is not accurate enough to either rule out or confirm the presence of cancer. PSA levels can be increased by various factors other than prostate cancer, including benign prostatic hyperplasia, prostatitis, advanced age, and ejaculation within 48 hours of the test. Relying too much on the test can lead to unnecessary biopsies. Not relying on it enough may miss cancers.
PSA screening may result in the detection of some possible cancers that would never have bothered the patient and would never have posed a threat to his life. Two major studies published in 2009 found that PSA screening saves few if any lives. As a result, the American Cancer Society does not recommend routine PSA testing, although individual men may choose to be tested.
Tests to Diagnose Prostate Cancer
Biopsy. If cancer is suspected, the doctor will order a biopsy. Only a biopsy, in which a tiny sample of prostate tissue is surgically removed, can actually confirm a diagnosis of prostate cancer. A biopsy is usually performed to confirm or rule out cancer based on a combination of PSA test levels, findings on the DRE, family history, and patient’s age and ethnicity. If a biopsy gives a negative result but the doctor still suspects cancer, repeat biopsies may be performed.
An ultrasound procedure called transrectal ultrasonography (TRUS) may be used to help the doctor see where to take the needle biopsy. Ultrasound is not effective as a diagnostic tool by itself because it cannot differentiate very well between benign inflammations and cancer.
Tests after Cancer is Diagnosed
PSA Levels and Velocity . Once cancer is diagnosed, PSA levels may help to determine its extent. If PSA levels are lower than 20 ng/mL, it is likely that the cancer has not spread to distant sites. PSA levels over 40 ng/mL are a strong indicator that cancer has metastasized (spread throughout the body). PSA levels are also monitored after treatments begin. Changes in the level can show if a treatment is working or if the cancer has come back.
Doctors also monitor how quickly PSA levels rise over time. This rate is called PSA velocity (PSAV). The PSAV may help determine when treatment should begin and which treatment should be used. A high rate of PSAV is considered to be 2 ng/mL a year. Recent research suggests that men with early-stage prostate cancer who have a slow PSAV are more likely to live longer than men with rapidly rising PSA levels.
Test for Metastasis . If the biopsy indicates cancer, the doctor will order other tests to determine whether or how far the cancer has spread:
- Bone scans and x-rays may reveal whether the cancer has invaded the bones. To perform a bone scan, doctors inject low doses of a radioactive substance into the patient's vein, which accumulates in bones that have been damaged by cancer. A scanner then reveals how much of the radioactive material has accumulated.
- Computed tomography (CT) or magnetic resonance imaging (MRI) scans can further pinpoint the location of cancer that has spread beyond the prostate.
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