From the Guidelines
You should not double the PSA value when a patient is on Avodart (dutasteride) as this method may result in unreliable cancer detection. The NCCN clinical practice guidelines for prostate cancer early detection, version 2.2015, suggest that the commonly employed method of doubling the measured PSA value to obtain an adjusted value may not be reliable due to the variable effect of 5-ARIs on PSA levels 1. In fact, failure to achieve a significant PSA decrease while taking 5-ARIs can indicate a heightened risk for prostate cancer that warrants regular testing.
Some key points to consider when interpreting PSA results for patients on dutasteride include:
- The effect of 5-ARIs on PSA levels is variable, with one study showing that after 12 months of treatment, only 35% of men demonstrated the expected 40% to 60% decrease in PSA 1
- Results from several clinical trials suggested that 5-ARIs enhance the predictive capacity of PSA, but reflex ranges for PSA among patients on 5-ARIs have not been established 1
- The PCPT and REDUCE trials demonstrated that finasteride and dutasteride reduced the incidence of prostate cancer, but the difference in the number of high-grade cancers detected did not result in a mortality difference 1
It's essential to establish a new baseline PSA after the patient has been on dutasteride for 6 months and to monitor trends over time rather than focusing on absolute values. Any rising PSA trend, even without adjustment, warrants further evaluation. The use of PSA testing alone can provide a diagnostic lead-time of 5 to 10 years, but the lead-time varies across studies, populations, and screening protocols 1.
From the FDA Drug Label
In clinical trials, dutasteride reduced serum PSA concentration by approximately 50% within 3 to 6 months of treatment... 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.
Yes, when a patient is on Avodart (dutasteride), you should double the PSA value for comparison with normal values in untreated men, as dutasteride reduces serum PSA concentration by approximately 50% within 3 to 6 months of treatment 2.
From the Research
Prostate Specific Antigen (PSA) and Avodart
- When a patient is on Avodart, it is essential to consider the effects of the medication on PSA levels.
- Avodart (dutasteride) can decrease PSA levels by approximately 50% after 6-12 months of treatment 3, 4.
- However, there is no direct evidence in the provided studies that suggests doubling PSA when a patient is on Avodart.
- The studies primarily focus on the comparison of digital rectal examination (DRE) and PSA in the early detection of prostate cancer, rather than the specific effects of Avodart on PSA levels.
Digital Rectal Examination (DRE) and PSA
- The combination of DRE and PSA can improve the detection of prostate cancer, especially in the early stages 5, 6.
- However, the diagnostic value of DRE as an independent test or as a supplementary measure to PSA is notably low, suggesting that it might not be necessary to conduct DRE routinely 6.
- A suspicious DRE can be a predictor of clinically significant prostate cancer, particularly if the DRE at diagnosis was negative 7.
PSA Screening and Avodart
- There is no direct evidence in the provided studies to suggest that Avodart affects the screening performance of PSA.
- However, it is crucial to consider the potential effects of Avodart on PSA levels when interpreting screening results.
- Further studies are needed to determine the optimal approach to PSA screening in patients taking Avodart.