Do you check Prostate Specific Antigen (PSA) when the prostate is absent?

PSA Testing After Prostatectomy

PSA testing is not indicated in patients who have undergone complete prostatectomy as there should be no prostate tissue remaining to produce PSA. 1

Rationale for Not Checking PSA After Prostatectomy

When a patient undergoes a complete radical prostatectomy, all prostate tissue is removed, including:

• The prostate gland itself
• Seminal vesicles
• Part of the urethra
• Surrounding tissues as needed

Expected PSA Levels Post-Prostatectomy

• After complete prostatectomy, PSA levels should drop to undetectable levels (typically <0.1 ng/mL) within 4-6 weeks
• Any detectable PSA after this period suggests:
  • Residual prostate tissue
  • Recurrent disease
  • Metastatic disease

Clinical Considerations

Biochemical Recurrence Monitoring

For patients who have undergone prostatectomy with curative intent:

• PSA monitoring is only indicated to detect recurrence, not as routine screening
• According to NCCN guidelines, serum PSA should be measured every 6-12 months for the first 5 years post-surgery and then annually 2
• More frequent monitoring (every 3 months) may be required for men at high risk of recurrence 2

Pattern of Recurrence

When prostate cancer recurs after radical prostatectomy:

• 45% of recurrences occur within the first 2 years
• 77% occur within 5 years
• 96% occur by 10 years 2

False Positives and Negatives

Without a prostate gland, there should be no source of PSA production unless:

1. The surgery was incomplete (some prostate tissue remains)
2. There is recurrent local disease
3. There is metastatic disease

Special Situations

After Partial Prostatectomy

In cases where only part of the prostate was removed (such as in some cases of benign prostatic hyperplasia):

• PSA testing may still be relevant as remaining prostate tissue will continue to produce PSA
• Baseline PSA should be established 1-3 months after surgery
• Subsequent PSA values should be interpreted in the context of the remaining prostate volume

After Radiation Therapy (Without Prostatectomy)

For patients who received radiation therapy but still have their prostate:

• PSA monitoring is recommended every 6 months for the first 5 years and then annually 2
• PSA levels typically decline slowly over 2-3 years after radiation therapy
• A rising PSA after reaching nadir suggests biochemical recurrence

Conclusion

In summary, routine PSA testing has no clinical utility in patients with complete absence of the prostate gland, as there should be no tissue to produce PSA. Any detectable PSA in this situation would indicate either incomplete surgery or recurrent/metastatic disease, warranting further evaluation.