Understanding PSA and DRE Results
Prostate specific antigen (PSA) is a protein that is normally made by the prostate gland. Since PSA levels tend to be higher in men with prostate cancer, PSA blood tests are often performed in healthy men to screen for the potential presence of prostate cancer, before any outward evidence of disease. PSA tests may be used at any point in time; many doctors will also use a series of PSA tests over time to help determine which patients might need a prostate biopsy.
PSA may be elevated for reasons other than prostate cancer. Prostate conditions like benign prostate hyperplasia (BPH), infection, and inflammation can also raise PSA levels. Ultimately, the decision about whether or not to undergo PSA testing should be made by each individual in consultation with his doctor. .
Historically, a PSA level of 4 ng/mL (nanograms per milliliter) or greater was generally regarded as high and raised concern for possible cancer. Some experts recommend even lower thresholds. A given PSA should be interpreted in light of a man’s age and other health factors to determine if a biopsy makes sense.
PSA Testing after a Prostate Cancer Diagnosis
If you have been diagnosed with prostate cancer, PSA levels are part of what your healthcare team will use to determine the overall risk of an aggressive cancer. A PSA level of less than 10 ng/mL is considered to indicate a low risk of aggressive disease. A level of 10-20 ng/mL indicates intermediate risk and a level greater than 20 ng/mL suggests a high risk of cancer progression. However, PSA only provides part of your overall cancer picture and should be considered with other clinical factors (e.g. biopsy results, clinical stage, and prostate size).
Many men diagnosed with prostate cancer due to elevated PSA levels have early-stage prostate cancer that is unlikely to progress in the near future. Such men may be able to avoid immediate treatment and be candidates for regular monitoring of their cancer through active surveillance. Genomic tests, like the Oncotype DX® Genomic Prostate Score1, may provide more clarity to men with low-risk prostate cancer about their individual cancer’s aggressiveness; this information may help make a more informed treatment decision.
PSA levels are usually checked to monitor men on active surveillance, after surgery or radiation therapy, and throughout hormonal therapy, immunotherapy and chemotherapy. If changes in PSA occur that might indicate disease progression, your doctor will discuss additional treatment options with you.
Digital Rectal Examination (DRE)
Doctors use a DRE (digital rectal exam) to screen for cancer, estimate the size of any cancer that is present, and assess treatment results
For this exam, your doctor will insert a gloved and lubricated finger into the rectum to examine your prostate for any abnormalities. Your prostate can be felt since it is on the other side of the rectal wall. Bear in mind that not all parts of the prostate can be felt on this exam. There may be some discomfort during the examination and the urge to urinate may be present. Doing the best you can to relax will help decrease discomfort during the exam.
1. Oncotype DX® is a registered trademark of Genomic Health, Inc.