Since 2009, three randomized controlled trials have been published showing that immediate adjuvant radiotherapy improves oncologic outcomes in men with adverse pathological features following prostatectomy. Unfortunately, adjuvant radiation poses a risk of overtreatment and treatment-related toxicity, including urethral stricture, incontinence, and proctitis, for those men who would otherwise be cured by surgery alone.
For these reasons, delayed, or salvage, radiotherapy, which reserves radiotherapy for those men who show early signs of recurrence, is an attractive alternative. Although the oncologic outcomes for delayed radiotherapy appear to be comparable to those for immediate radiotherapy based on observational studies, evidence is still emerging. On the other hand, despite supporting level 1 evidence, adjuvant radiation utilization has been shown to be low in several recent studies. The impact of delayed radiotherapy usage on this practice pattern has been unclear.
From 2004 to 2009 (with followup through 2011), we found that only 10% of men with adverse pathologic features actually received postprostatectomy radiation. In accordance with the randomized controlled trial data, 7.3% of men received immediate radiotherapy (within 4.5 months of prostatectomy), while the remaining 2.8% of men received delayed radiotherapy (within 4.5 months to 2 years of prostatectomy). These findings suggest that as many as 90% of men may be undertreated. Furthermore, we analyzed the impact of delayed radiotherapy on immediate radiotherapy utilization. We noted that postprostatectomy radiotherapy is significantly more likely to be performed in a delayed rather than immediate fashion over time; however, given the low utilization of both immediate and delayed radiotherapy, the magnitude of this change is very small and of questionable clinical significance.
Although the utilization of immediate radiotherapy is low, when it is used, its use appears to be driven by appropriate clinical and pathological factors. In particular, men with positive surgical margins and/or seminal vesicle invasion, and younger men, all of whom may derive the greatest benefit and least harm from immediate radiotherapy, are more likely to be treated. Interestingly, men with positive lymph nodes are also more likely to receive immediate radiotherapy, a practice that is currently investigational.
In summary, immediate radiotherapy is still being underutilized after prostatectomy, and this underutilization does not appear to be explained entirely by the use of delayed radiotherapy, which is also low. Urologists should discuss the risks, benefits, and evidence behind immediate vs. delayed radiotherapy with their patients. For those patients who are considering postoperative radiotherapy, referral to a radiation oncologist may be beneficial.
Matthew J. Maurice, MD
Urology Institute, University Hospitals Case Medical Center, Cleveland, OH.