Management of Rising PSA in an 84-Year-Old Man on Finasteride
A prostate biopsy is strongly recommended for this 84-year-old man on finasteride with a PSA increase from 1.5 to 3.7 ng/mL, as this represents a significant rise that exceeds the threshold for concern in patients on 5α-reductase inhibitors. 1, 2
Understanding PSA Changes on Finasteride
- Finasteride typically reduces serum PSA by approximately 50% within six months of treatment, and this decrease is predictable across the entire range of PSA values 2
- For men on finasteride for six months or more, PSA values should be doubled for comparison with normal ranges in untreated men 2
- After establishing a nadir PSA level on finasteride, any confirmed increase from the lowest PSA value may signal the presence of prostate cancer and should be evaluated 2
Analysis of This Patient's PSA Change
- Doubling the current PSA of 3.7 ng/mL yields an adjusted value of 7.4 ng/mL, which exceeds the standard 4.0 ng/mL threshold for biopsy consideration 1, 2
- The increase from 1.5 to 3.7 ng/mL represents a 2.2 ng/mL absolute increase, which exceeds the 1.0 ng/mL threshold that warrants prostate biopsy in men on 5α-reductase inhibitors 1
- This rise is particularly concerning as men on finasteride should typically show a median annual decrease of 2% in PSA after the first year, not an increase 3
Recommended Diagnostic Approach
- Confirm the elevated PSA with a repeat test to rule out laboratory variability 4
- Perform a digital rectal examination (DRE) to assess for any abnormalities 4
- Proceed with transrectal ultrasound-guided prostate biopsy, typically taking 10-12 core samples 4
- The biopsy, not the PSA test, is what definitively determines whether a man has prostate cancer 1
Special Considerations for Elderly Patients
- While many prostate cancers grow slowly and may not impact survival in elderly men, those that grow more rapidly can potentially affect overall survival and quality of life 1
- The decision to pursue biopsy should consider that approximately 7 in 10 prostate cancer deaths occur in men aged 75 and older 1
- Despite age, the significant PSA rise in this patient warrants further investigation as it exceeds established thresholds for concern 1
Potential Pitfalls and Caveats
- PSA can be elevated due to benign conditions such as prostate enlargement, which is common in older men 5
- A prostate biopsy can occasionally miss cancer when present, and a negative biopsy does not completely rule out cancer 1
- Prostate biopsy complications, while infrequent, can include rectal or urinary hemorrhage, infection, or urinary retention 1
- The higher the PSA level, the more likely a man will be found to have prostate cancer if a biopsy is performed (approximately 1 in 3 men with PSA between 4-10 ng/mL have prostate cancer) 1, 4
Follow-up Recommendations After Biopsy
- If biopsy is negative, continue monitoring PSA levels every 3-6 months 1
- For any further PSA increase of 0.7-0.9 ng/mL, repeat PSA testing in 3-6 months 1
- For any further PSA increase of 1.0 ng/mL or more, consider repeat biopsy 1
- If prostate cancer is diagnosed, treatment options will depend on Gleason score, clinical stage, and the patient's overall health and preferences 4