Prostate-Specific Antigen (PSA) Following Radical Prostatectomy

Radical prostatectomy is a surgical procedure employed for treating localised prostate cancer. However, the surgical intervention does not signify the end of the treatment process; instead, it marks the beginning of a post-operative surveillance phase. This is essential for determining the procedure's efficacy in eradicating the cancerous cells and identifying any possible disease recurrence. This article delves into the importance of prostate-specific antigen (PSA) surveillance following a radical prostatectomy.

What are Surgical Margins?

When a prostate is removed it is sent to the histology lab to be worked up. The outside surface is cut. The pathologist will look to see if there is prostate cancer touching the inked surface or not.

Positive Surgical Margin vs. Negative Surgical Margin

• Positive Surgical Margin: Indicates the presence of cancer cells at the periphery of the excised tissue. In such instances, residual prostate cancer cells are at risk and may necessitate further treatment.

• Negative or Clear Surgical Margin: This means that all of the prostate cancer was removed, with a layer of healthy tissue covering the area where the cancer was cut out.

What is an "undetectable PSA"?

Following a radical prostatectomy, the PSA levels should ideally drop to "undetectable." Generally, undetectable PSA levels fall below 0.03 ng/mL. However, these values can differ depending on the specific laboratory that carries out the PSA test. Some labs may report levels below 0.01 ng/mL. In such cases, the reading is considered negligible and thus undetectable.

Postoperative PSA Surveillance Protocol

How often should I check my PSA after my prostate has been taken out?

It is recommended to monitor PSA at intervals of:

• Three to four months for the first two years post-surgery
• Six-month intervals until five years post-surgery
• Annual checks if PSA remains undetectable

How would I know if my prostate cancer is back?

Any presence or detectable PSA raises concern. PSA level of 0.2 ng/mL or above need means diagnostic tests are needed to identify the site of recurrence.

Imaging Techniques

1. MRI Scan: Used for high-resolution imaging of the pelvic region.
2. PSMA PET Scan: Highly sensitive in detecting prostate cancer metastasis.

It's worth mentioning that imaging tests might struggle to locate cancers when the PSA level is extremely low.

Challenges in Detection

Low levels of PSA can present challenges in identifying clusters of cancer cells. Even sophisticated imaging modalities may not detect these, requiring further investigation.

Recent Advances: The RADICALs Trial

Recent studies, such as the RADICALs trial, suggest that when PSA levels exceed twice the threshold of 0.1 ng/mL, a multi-modal treatment approach involving radiotherapy and hormone therapy is often recommended.

Reflection of a robotic prostate surgeon.

Postoperative PSA surveillance is an indispensable aspect of prostate cancer management following radical prostatectomy. Understanding the terminology and monitoring guidelines can equip patients and healthcare providers to make informed decisions in the event of a recurrence. Keeping abreast of the latest research, such as the RADICALs trial, can also help optimise the management of recurrent prostate cancer.

References

[1] Freedland, S. J., Humphreys, E. B., Mangold, L. A., Eisenberger, M., Dorey, F. J., Walsh, P. C., & Partin, A. W. (2005). Risk of Prostate Cancer-Specific Mortality Following Biochemical Recurrence After Radical Prostatectomy. JAMA, 294(4), 433–439.

[2] Swindle, P., Eastham, J. A., Ohori, M., Kattan, M. W., Wheeler, T., Maru, N., ... & Scardino, P. T. (2005). Do Margins Matter? The Influence of Positive Surgical Margins on Prostate Cancer-Specific Mortality. European Urology, 47(4), 1-7.

[3] Lepor, H., & Kaci, L. (2004). The Impact of Open Radical Retropubic Prostatectomy on Continence and Lower Urinary Tract Symptoms: A Review. Urology, 63(3), 9-17.

[4] Pound, C. R., Partin, A. W., Eisenberger, M. A., Chan, D. W., Pearson, J. D., & Walsh, P. C. (1999). Natural History of Progression After PSA Elevation Following Radical Prostatectomy. JAMA, 281(17), 1591–1597.

[5] Amling, C. L., Bergstralh, E. J., Blute, M. L., Slezak, J. M., & Zincke, H. (2000). Defining Biochemical Recurrence of Prostate Cancer After Radical Prostatectomy: A Proposal for a Standardized Definition. Journal of Clinical Oncology, 18(15), 2745–2752.

[6] Rosenkrantz, A. B., Verma, S., Choyke, P., Eberhardt, S. C., Eggener, S. E., Gaitonde, K., ... & Weinreb, J. C. (2016). Prostate Magnetic Resonance Imaging and Magnetic Resonance Imaging Targeted Biopsy in Patients with a Prior Negative Biopsy: A Consensus Statement by AUA and SAR. The Journal of Urology, 196(6), 1613–1618.

[7] Hofman, M. S., Lawrentschuk, N., Francis, R. J., Tang, C., Vela, I., Thomas, P., ... & Davis, I. D. (2020). Prostate-specific Membrane Antigen PET-CT in Patients with High-risk Prostate Cancer Before Curative-intent Surgery or Radiotherapy (proPSMA): A Prospective, Randomised, Multicentre Study. The Lancet, 395(10231), 1208–1216.

[8] Siddiqui, M. M., Rais-Bahrami, S., Turkbey, B., George, A. K., Rothwax, J., Shakir, N., ... & Pinto, P. A. (2015). Comparison of MR/Ultrasound Fusion–Guided Biopsy With Ultrasound-Guided Biopsy for the Diagnosis of Prostate Cancer. JAMA, 313(4), 390–397.

[9] Parker, C., Clarke, N., Logue, J., Payne, H., Catton, C., Kynaston, H., ... & Sydes, M. R. (2020). RADICALS (Radiotherapy and Androgen Deprivation in Combination After Local Surgery). The Lancet, 396(10260), 1413–1421.