What does a fluctuating PSA mean?

I am 59 years old and have a fluctuating PSA. In 2005, it was 2.5 ng/ml. A 12-core biopsy was negative. In 2006, my PSA dropped to 0.97 ng/ml. In 2007, it went up to 2.54, and I had another biopsy. All 14 cores were negative for cancer. What does this mean for my prostate health?

Kevin Loughlin, M.D., M.B.A., director of Urologic Research at Brigham and Women’s Hospital, responds:

Variations in PSA like yours aren’t particularly remarkable. In fact, fluctuations in PSA of up to 36% from one day to the next may have nothing to do with cancer. Prostate infections and inflammation may account for some of the variation, as can an enlarged prostate and advancing age. However, the Prostate Cancer Prevention Trial found that prostate cancer might be detected in 23.9% of patients with a PSA of 2.1 to 3 ng/ml, so you don’t want to ignore an elevated PSA either.

Before you have a third biopsy, consider having your free PSA measured.  A 2008 study of 125 men who had a prostate biopsy showed that the percentage of free PSA in men with a total PSA of 2.5 ng/ml or less could indicate who was most likely to have prostate cancer: 59% of the men with a free PSA of 14% or less had prostate cancer versus just 13% of the men with a free PSA of 28% or more. So the lower your percentage of free PSA, the more you might want to think about having another biopsy.

You could also ask about having an endorectal MRI. This imaging test can help physicians spot abnormalities in regions of the prostate not typically sampled during a biopsy. Any follow-up biopsies could then target those suspicious areas.

Assuming the endorectal MRI and your digital rectal examination (DRE) are normal, and depending on your general health and any medications you take, you and your doctor might simply want to track your PSA over time. If it jumps much above its current level, you could opt for a biopsy then.

Unfortunately, there is no one right answer to your question. In the end, it comes down to combining all of the data you have, talking with your doctor, and making an educated decision about what to do next.

SOURCES: Lawrentschuk N, Fleshner N. The Role of Magnetic Resonance Imaging in Targeting Prostate Cancer in Patients with Previous Negative Biopsies and Elevated Prostate-Specific Antigen Levels. BJU International 2009;103:730–33. PMID: 19154475.

Walz J, Haese A, Scattoni V, et al. Percent Free Prostate-Specific Antigen (PSA) Is an Accurate Predictor of Prostate Cancer Risk in Men with Serum PSA 2.5 ng/ml and Lower. Cancer 2008;113:2695–703. PMID: 18853417.

Originally published November 2009; last reviewed March 16, 2011.