Prostate-Specific Antigen (PSA) testing is a common blood test used to monitor prostate health, but its results can be complex to interpret, especially in older men. The test measures a protein produced by the prostate gland, and its level in the blood can be influenced by various factors, including age. For a man around age 70, understanding what a normal PSA level means requires moving beyond a single cutoff number. Interpretation must consider the specific context of age-related changes, ensuring decisions about further testing weigh potential benefits against possible harm.
Understanding Prostate-Specific Antigen
Prostate-Specific Antigen (PSA) is a protein produced by the epithelial cells of the prostate gland. Its primary function is in the ejaculate, where it helps to liquefy the semen and allow sperm to swim freely. A small amount naturally leaks into the bloodstream, where it can be measured with a blood test.
The PSA test measures the concentration of this protein in nanograms per milliliter (ng/mL) of blood. Total PSA measures the combined amount of PSA that is bound to other proteins and the fraction that circulates unbound, known as free PSA. Conditions like prostate cancer or benign enlargement can disrupt the prostate’s structure, causing more PSA to enter the bloodstream and resulting in an elevated total PSA level. The ratio of free PSA to total PSA can provide additional information, as a lower percentage of free PSA may suggest a greater likelihood of prostate cancer.
Interpreting PSA Levels for Men Aged 70
For many years, a total PSA level below 4.0 ng/mL was considered the general cutoff for a normal result, regardless of age. Medical understanding has evolved, recognizing that PSA levels naturally increase as men age, even without cancer, due to the natural enlargement of the prostate gland. For men in their 70s, age-specific ranges are now widely used to provide a more accurate interpretation.
Many clinicians consider a PSA level up to 6.5 ng/mL to be within the typical range for men aged 70 and older. For men in their early 70s (70-74), the upper limit of the normal range can be around 9.0 ng/mL, though this varies significantly. A level above 4.0 ng/mL does not automatically indicate cancer, but it suggests a higher probability of prostate enlargement or another issue.
When a reading is consistently above the expected threshold for this age group, such as above 6.5 ng/mL, it warrants further investigation. A level over 10.0 ng/mL is highly elevated and significantly increases the likelihood of cancer, often prompting a prostate biopsy. Clinicians also focus on PSA velocity, measuring how quickly the level changes over time, as a rapid increase is more concerning than a single, mildly elevated number.
Non-Disease Factors That Influence PSA Results
Interpreting a PSA result is complicated because many non-cancerous conditions and physical activities can temporarily or permanently alter the level. Benign Prostatic Hyperplasia (BPH), the non-cancerous enlargement of the prostate common in older men, is a frequent cause of elevated PSA. As the gland grows, it produces more PSA, increasing the amount that leaks into the bloodstream.
Prostatitis, inflammation or infection of the prostate gland, can cause a significant, but often temporary, spike in PSA. Other forms of manipulation or physiological stress on the prostate can transiently increase the measurement, including a recent digital rectal exam (DRE), prostate biopsy, or catheterization. Activities like ejaculation or vigorous exercise, such as long-distance cycling, should be avoided for 48 hours before the blood draw, as they can cause a temporary rise in PSA.
Certain medications can also suppress PSA levels, leading to a falsely low reading. Specifically, 5-alpha reductase inhibitors (5-ARIs), such as finasteride and dutasteride, prescribed to treat BPH, can reduce the total PSA level by about 50%. Physicians typically adjust the PSA reading by doubling the test result for men taking these medications to get a comparable value.
The Shared Decision-Making Process for PSA Screening
For men aged 70 and older, the decision to continue or begin PSA screening becomes highly individualized, moving toward shared decision-making (SDM). Major medical guidelines, such as those from the U.S. Preventive Services Task Force (USPSTF), recommend against routine PSA-based screening for this age group. This recommendation is based on the finding that the potential harms of screening often outweigh the potential benefits.
The core issue is the risk of overdiagnosis and overtreatment, which is particularly relevant in older men. Many prostate cancers grow very slowly and would never cause symptoms or shorten a man’s life, especially if he has other existing health conditions. Detecting these slow-growing cancers often leads to treatment with surgery or radiation, which carries risks of complications like urinary incontinence and sexual dysfunction.
Shared decision-making involves a detailed conversation between the patient and physician exploring the patient’s overall health status, life expectancy, and personal preferences regarding screening and treatment risks. If a man over 70 has a life expectancy less than 10 to 15 years, the benefits of screening are generally considered negligible. Conversely, a very healthy 70-year-old with a long life expectancy might still benefit, making the discussion about individual values and health status paramount.
Discussions should cover both the advantages of potentially finding an aggressive, curable cancer and the disadvantages of unnecessary biopsies and the side effects of treating a non-aggressive tumor. This collaborative approach ensures that the decision to undergo or stop PSA testing aligns with the individual’s priorities and clinical situation, rather than a universal age cutoff.