What is the next step in management for a 63-year-old male with a history of radical prostatectomy for Gleason 7 prostate cancer, presenting with slow stream, incomplete evacuation, and occasional right flank pain, currently taking Plavix (clopidogrel) and Aspirin (acetylsalicylic acid), with upcoming PSA test results?

Management of Post-Prostatectomy Patient with Urinary Symptoms and Flank Pain

For a 63-year-old male with history of radical prostatectomy for Gleason 7 prostate cancer presenting with slow stream, incomplete evacuation, and right flank pain, the most appropriate next step is to evaluate the PSA test results and perform a comprehensive urologic evaluation including cystoscopy and urodynamic studies to assess for bladder outlet obstruction or anastomotic stricture. 1

Evaluation of PSA Results

When the patient returns tomorrow, the following approach should be taken:

1. Review PSA results carefully:

   • PSA should be undetectable (<0.1 ng/mL) after radical prostatectomy
   • Any detectable PSA (≥0.2 ng/mL) is concerning for biochemical recurrence 1
   • PSA values between 0.1-0.2 ng/mL warrant close monitoring with repeat testing in 1-3 months 1

2. Interpret PSA based on timing:

   • PSA should be measured every 6-12 months for the first 5 years post-prostatectomy 1
   • More frequent testing (every 3 months) may be required for high-risk patients 1
   • Note that the patient is 5 years post-prostatectomy, which is a critical timepoint as 77% of recurrences occur within the first 5 years 1

Management Algorithm Based on PSA Results

If PSA is undetectable (<0.1 ng/mL):

• Focus on evaluating urinary symptoms:
  • Perform cystoscopy to evaluate for anastomotic stricture, which is a common cause of slow stream and incomplete emptying after prostatectomy
  • Consider urodynamic studies to assess bladder function and outlet resistance
  • Evaluate flank pain with contrast-enhanced CT scan if not already done, as normal renal ultrasound doesn't exclude all urologic pathology

If PSA is detectable (≥0.2 ng/mL):

1. Confirm PSA elevation with repeat testing in 1-3 months 1
2. Estimate PSA doubling time - shorter doubling time (<6 months) suggests metastatic recurrence rather than local recurrence 1
3. Consider imaging studies:
   • MRI of the pelvis to evaluate for local recurrence 1
   • Bone scan if PSA >10 ng/mL or if symptoms suggest bone metastasis 1
   • Consider newer imaging modalities like PET scans with prostate-specific tracers if available 1
4. Plan for salvage radiotherapy if no evidence of distant metastasis 1
   • Earlier salvage radiotherapy (PSA <0.5 ng/mL) has better outcomes than delayed treatment 1

Important Considerations

• Medication effects: The patient is on Plavix and aspirin, which may affect PSA levels minimally 2 but are more concerning for bleeding risk if invasive procedures are needed
• Timing of PSA test: Ensure PSA was drawn at least 6-8 weeks after any prostate manipulation or infection to avoid false elevations 3
• Digital rectal examination: Although deferred in this visit, should be performed annually to monitor for local recurrence and colorectal cancer screening 1
• Bleeding noted on examination: Lower extremity bleeding should be evaluated in context of dual antiplatelet therapy (Plavix and aspirin)

Pitfalls to Avoid

1. Don't ignore detectable PSA: Even very low detectable PSA levels can indicate recurrence and should prompt consideration of salvage therapy 1
2. Don't delay salvage radiotherapy: Outcomes are significantly better when salvage RT is initiated at lower PSA levels (<0.5 ng/mL) 1
3. Don't attribute all symptoms to cancer recurrence: The patient's urinary symptoms may be due to anastomotic stricture or bladder dysfunction rather than recurrence, especially with normal renal ultrasound and minimal post-void residual
4. Don't forget to assess cardiovascular status: The patient has history of angioplasty and is on dual antiplatelet therapy; cardiovascular abnormalities were noted on exam

By following this structured approach based on the PSA results, you can determine whether the patient's symptoms are related to cancer recurrence or other urologic conditions, and develop an appropriate management plan that addresses both oncologic and functional concerns.