09/11/2003 - Questions and Answers

Fluctuations in PSA Results

By: Mark Castleden



I am 76 years old. In 1992 my PSA was 2.4, in 1995 it was 2.5, and in April 2001 it was 7.0. But then in September 2001 it was 4.4, my 'free' PSA was 1.4 and the percentage 'free' PSA was 32%. What caused this fluctuation in a five-month period?


PSA stands for Prostate-Specific Antigen; it's measured as a test for prostate cancer. PSA fluctuations are very common and very frustrating at the same time. In general, in a man aged 75 or greater, a PSA of 5 to 5.5 is considered relatively normal, assuming no great alteration in the number from year to year (i.e. less than 0.75 change each year). Additionally, in a man with a very large gland, it is not unusual for the PSA to be somewhat higher at baseline. This is known as PSA density. The fact that your percentage 'free' PSA (i.e. the amount that isn't combined with protein in the blood) is above 20% is a good sign.

PSA fluctuates because of various factors. Diet, fluid intake, infection or inflammation of the prostate, pressure around the prostate (e.g. bicycle-riding), recent ejaculation, recent surgery or catheterization . . .all can alter the values.

In the case of a raised PSA, it's often recommended that patients avoid any caffeine, alcohol or spicy foods, drink 2 liters of water a day, ejaculate twice-a-week (but not 48 hours before their repeat PSA) and take 2-4 weeks of an antibiotic (e.g. Cipro, Bactrim), and then repeat the PSA. This procedure is repeated every 3 months. If there's a constant increase in the baseline number, a biopsy of the prostate is recommended, to rule out cancer.


Created on: 02/20/2002
Reviewed on: 09/11/2003

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