Prostate cancer is a common malignancy affecting men. For many diagnosed with localized prostate cancer, surgical removal of the prostate gland, known as a prostatectomy, is a primary treatment. While surgery often removes cancerous tissue, radiation therapy is sometimes considered to further reduce recurrence risk. This article explores radiation treatment following a prostatectomy.
Understanding Radiation After Prostatectomy
A prostatectomy involves the surgical removal of all or part of the prostate gland, a small gland located in the pelvis beneath the bladder. This procedure is most commonly performed to treat prostate cancer that is believed to be confined to the gland. Following surgery, radiation therapy may be administered in two distinct scenarios.
One scenario is “adjuvant radiation,” given immediately or soon after surgery, typically within one year. This treatment is administered even if no detectable cancer remains, based on pathological findings from the removed prostate. Its purpose is to eliminate any microscopic cancer cells that might have been missed during surgery, aiming to reduce the risk of future recurrence.
A different approach is “salvage radiation,” administered later if prostate-specific antigen (PSA) levels begin to rise after surgery. A rising PSA indicates that some cancer cells may have been left behind or that the cancer has recurred. Salvage radiation targets these residual or recurring cancer cells to control the disease and lower PSA levels.
How Treatment Success Is Measured
The success of radiation therapy after a prostatectomy is assessed by monitoring biochemical recurrence-free survival. This metric relies on prostate-specific antigen (PSA) levels, which are routinely measured through blood tests after surgery. A consistently low or undetectable PSA level indicates that the treatment has successfully controlled the cancer.
For patients who have undergone a prostatectomy, biochemical recurrence is defined as two consecutive PSA values of 0.2 ng/mL or higher. Maintaining an undetectable PSA level after radiation is an indicator of treatment success. While PSA is the most common measure, other metrics, such as clinical recurrence-free survival (absence of detectable tumor growth) and overall survival, are also considered to evaluate long-term outcomes.
Factors Influencing Success and Expected Outcomes
Several factors influence the success rates of radiation after prostatectomy. Pathological findings from the prostatectomy are highly informative. The Gleason score, which indicates the aggressiveness of the cancer, plays a role; men with a Gleason score of 7 or higher may have a lower biochemical recurrence-free likelihood compared to those with scores less than 7. The status of surgical margins—whether cancer cells were found at the edges of the removed tissue (positive margins) or not (negative margins)—also impacts outcomes, with positive margins associated with a higher risk of recurrence.
The extent of cancer spread beyond the prostate capsule (extracapsular extension), invasion into the seminal vesicles, or involvement of lymph nodes are additional factors. These indicate more advanced disease, potentially lowering the success rate of local radiation therapy alone. For example, seminal vesicle invasion is an adverse finding that decreases long-term freedom from biochemical recurrence, a magnitude of impact exceeded only by lymph node metastases.
Pre-radiation PSA levels are important for salvage radiation. Studies indicate that lower PSA levels at the time of initiating salvage radiation are associated with better outcomes. For instance, the 5-year biochemical control rate for salvage radiation can be around 56%, with lower pre-salvage PSA values correlating with improved control. Patients receiving salvage radiation with a PSA less than 0.2 ng/mL may have a 5-year biochemical recurrence-free survival rate over 70%, which drops to over 60% for PSA levels between 0.2 and 0.5 ng/mL.
The timing of radiation, whether adjuvant or salvage, also influences success. While early trials showed conflicting results, some studies suggest that adjuvant radiation may offer a biochemical progression-free survival advantage for men with adverse pathological features. However, recent long-term follow-up from randomized trials has indicated that adjuvant radiation after radical prostatectomy did not improve freedom from distant metastasis or overall survival at 10 years compared to salvage radiation, although it did add toxicity. For favorable pathology, waiting for PSA to rise before initiating salvage therapy may be a safe approach.
What to Expect During and After Treatment
External beam radiation therapy (EBRT) is a common method used after prostatectomy. The process begins with a planning phase, including CT and MRI simulations, to precisely map the treatment area. Patients receive daily treatments, usually five days a week, over several weeks, often around seven weeks. The radiation is painless, similar to an X-ray.
During treatment, patients may experience short-term side effects. Common urinary symptoms include increased frequency, urgency, and discomfort or burning during urination. Bowel changes, such as diarrhea, increased frequency of bowel movements, or rectal irritation, can also occur due to proximity to the bowel and rectum. Fatigue is another common symptom that often worsens as treatment progresses. These side effects are temporary and improve within weeks or months after treatment concludes.
Less common or long-term side effects can include persistent urinary or bowel issues, and a risk of erectile dysfunction or dry orgasm. Ongoing follow-up care is part of post-radiation management. Regular PSA monitoring continues after treatment to track long-term success and detect any potential recurrence, guiding further management decisions.