What is the next step for a patient on finasteride (Propecia) with a rising Prostate-Specific Antigen (PSA) level?

From the Guidelines

For a patient on finasteride with a rising PSA level, the next step should be prompt referral to a urologist for further evaluation, including consideration of a prostate biopsy. This is because finasteride typically reduces PSA levels by approximately 50%, so any increase in PSA while on this medication is particularly concerning and warrants investigation 1. The urologist will likely perform a thorough assessment including digital rectal examination and may order additional tests such as free PSA, PSA density, or advanced imaging like multiparametric MRI before deciding on biopsy. When interpreting PSA values for patients on finasteride, clinicians should double the measured PSA value to estimate what it would be without medication effect, as suggested by studies 1. The rate of PSA rise (PSA velocity) is also significant, with increases of more than 0.75 ng/mL per year raising concern for possible prostate cancer. This careful monitoring is necessary because finasteride can mask prostate cancer by artificially lowering PSA levels, potentially delaying diagnosis if rising values aren't properly investigated. Some key points to consider in the evaluation of a patient on finasteride with a rising PSA include:

• The impact of finasteride on PSA levels, which can lower them by approximately 50% 1
• The need to double the measured PSA value to estimate the true PSA level without the effect of finasteride 1
• The significance of PSA velocity, with increases of more than 0.75 ng/mL per year raising concern for possible prostate cancer
• The importance of a thorough assessment, including digital rectal examination and additional tests as needed, to determine the cause of the rising PSA level. It's also important to consider the guidelines for prostate cancer surveillance, which recommend measuring serum PSA level every 6 to 12 months for the first 5 years, then rechecking annually thereafter, and referring survivors with elevated or rising PSA level back to the primary treating specialist for further follow-up and treatment 1.

From the FDA Drug Label

In clinical studies, finasteride tablets reduced serum PSA concentration by approximately 50% within six months of treatment. ... Any confirmed increase from the lowest PSA value while on finasteride tablets may signal the presence of prostate cancer and should be evaluated, even if PSA levels are still within the normal range for men not taking a 5α-reductase inhibitor. To interpret an isolated PSA value in patients treated with finasteride tablets for six months or more, PSA values should be doubled for comparison with normal ranges in untreated men.

The patient's PSA level has increased from 2.4 to 2.8 while on finasteride 1 mg daily. Doubling the PSA value for comparison with normal ranges in untreated men gives a value of 4.8 to 5.6. Given this increase, the proper next step for the urologist is to evaluate the patient for potential prostate cancer, as any confirmed increase from the lowest PSA value while on finasteride may signal its presence 2.

From the Research

Next Steps for a Patient on Finasteride with a Rising PSA Level

The patient in question is taking finasteride 1 mg daily and has experienced a rise in Prostate-Specific Antigen (PSA) level from 2.4 to 2.8. The following are potential next steps for the urologist:

• Assess the adequacy of the initial biopsy, if one has been performed, to determine if a repeat biopsy is necessary 3
• Consider the patient's overall risk factors for prostate cancer, including age, family history, and PSA velocity, to determine the best course of action 4
• Evaluate the patient's PSA level in the context of finasteride treatment, taking into account that finasteride can reduce PSA levels by approximately half 4

Considerations for Repeat Biopsy

If a repeat biopsy is deemed necessary, the following considerations should be taken into account:

• A minimum of 14 cores should be obtained, including 2 additional cores from the right and left anterior apex 3
• The patient's PSA level and other risk factors should be taken into account when determining the timing and necessity of a repeat biopsy 4

Comparison of Finasteride and Other Treatments

Finasteride has been compared to other treatments, such as dutasteride, in terms of its effectiveness in reducing the risk of prostate cancer:

• A pooled analysis of 15 real-world databases found that finasteride was associated with a lower risk of prostate cancer compared to dutasteride in patients with benign prostatic hyperplasia (BPH) 5
• However, another study found that the impact of finasteride on PSA levels and prostate cancer risk is similar to that of other treatments, with the exception of the approximate reduction of PSA by half with finasteride 4

Follow-up Care

The patient's follow-up care should be individualized based on their specific risk factors and PSA level:

• A study of 13,591 veterans found that follow-up care after an elevated PSA test was highly variable, with more than a third of men receiving care that could be considered incomplete 6
• The urologist should consider the patient's overall health and risk factors when determining the best course of follow-up care, including additional PSA testing, urology consults, and biopsies 6