From the FDA Drug Label
In clinical trials, dutasteride reduced serum PSA concentration by approximately 50% within 3 to 6 months of treatment. The average decrease in PSA for a 66-year-old male taking dutasteride is approximately 50% within 3 to 6 months of treatment 1. To interpret an isolated PSA value in a man treated with dutasteride for 3 months or more, the PSA value should be doubled for comparison with normal values in untreated men.
From the Research
The average increase in PSA for a 66-year-old male is approximately 0.04 to 0.07 ng/mL per year, as supported by the most recent and highest quality study available 2. This rate of change is considered normal age-related PSA velocity for men in their 60s. A healthy 66-year-old man typically has a PSA level below 4.0 ng/mL, though this can vary based on individual factors. It's essential to understand that PSA naturally increases with age due to gradual prostate enlargement (benign prostatic hyperplasia) that occurs in most men as they get older. While monitoring PSA is crucial, a single elevated reading should not cause immediate alarm, as factors like prostate inflammation, recent ejaculation, or certain medications can temporarily increase PSA levels. Some key points to consider:
- Regular annual PSA testing is recommended for men in this age group to establish a personal baseline and track changes over time.
- A PSA increase of more than 0.75 ng/mL per year or a doubling of PSA in less than 2 years may warrant further evaluation by a urologist, as this rate of increase could potentially indicate prostate cancer.
- Age-adjusted PSA reference values may help increase the positive predictive value (PPV) for prostate cancer detection, as seen in studies like 3.
- The use of 5-alpha-reductase inhibitors (5ARI) may reduce the risk of prostate cancer, but may also increase the risk of high-grade disease in men undergoing regular screening, as noted in 4. However, the most recent and highest quality study 2 provides the best evidence for the average increase in PSA for a 66-year-old male.