Prostate-Specific Antigen (PSA) is a protein produced predominantly by the cells of the prostate gland. A radical prostatectomy surgically removes the entire prostate gland, eliminating the primary source of this protein. Monitoring the PSA level after surgery is the most reliable way to track the procedure’s success and monitor for disease recurrence. The goal is to reduce circulating PSA to its lowest possible level, providing a clear benchmark for long-term surveillance.
The Target: What Undetectable PSA Means
The ideal outcome following a successful radical prostatectomy is for the PSA level to become “undetectable.” This confirms the surgery effectively removed all PSA-producing tissue, including cancerous cells. While absolute zero is rare due to the sensitivity of modern tests, the target threshold is generally defined as less than 0.1 nanograms per milliliter (ng/mL). Some highly sensitive tests may report values below 0.05 ng/mL as the limit of detection.
The lowest point reached after surgery is called the PSA nadir. Achieving a stable, undetectable nadir defines a successful cancer removal. A low, stable reading indicates that any minute amount of PSA is likely produced by non-prostate sources or benign tissue, rather than residual or recurrent cancer cells. The PSA level should reach this undetectable state within six to eight weeks after the operation.
Defining Biochemical Recurrence
A rise in PSA after the nadir signals the possibility that prostate cells, and potentially cancer cells, remain in the body. This laboratory finding is known as biochemical recurrence (BCR). For patients who have had a radical prostatectomy, the accepted definition for BCR is two consecutive PSA measurements of 0.2 ng/mL or higher.
Physicians require two rising measurements to confirm recurrence, ruling out temporary fluctuations or laboratory variability. BCR is not the same as clinical recurrence, which involves symptoms or visible tumors on imaging. Instead, BCR serves as an early warning sign, indicating the presence of active PSA-producing prostate cells that require further investigation and timely intervention.
Post-Surgery Monitoring Schedule
Following the initial post-operative PSA test, a structured monitoring schedule tracks the long-term trend of the PSA level. Surveillance typically begins a few months after surgery and continues for many years to ensure quick detection of any potential recurrence. Testing frequency is higher in the first five years, often every six to twelve months.
If the PSA remains undetectable after the initial five-year period, testing is often reduced to an annual basis. Beyond the absolute PSA number, doctors also monitor the PSA velocity (the rate at which the level is rising) and the PSA doubling time. A faster doubling time suggests a more aggressive biological process and influences the urgency of subsequent treatment decisions.
Treatment Options After Recurrence
If biochemical recurrence is confirmed by two rising PSA levels crossing the 0.2 ng/mL threshold, salvage treatment options are discussed. The primary goal of subsequent therapy is to return the PSA level to the undetectable range. The most common approach is Salvage Radiation Therapy (SRT), which delivers targeted radiation to the area where the prostate gland was located.
SRT is often administered when the PSA is still low, as this increases the chance of success. Hormone therapy, specifically Androgen Deprivation Therapy (ADT), is often used in combination with SRT to enhance radiation effectiveness. Advanced imaging techniques, such as the PSMA PET scan, may be used before treatment to help locate the exact site of recurrence.