More Extensive Lymph Node Dissection at Radical Prostatectomy is Associated with Improved Outcomes with Salvage Radiotherapy for Rising Prostate-specific Antigen After Surgery: A Long-term, Multi-institutional Analysis

Up to 50% of patients recur after salvage radiation therapy (sRT) for prostate-specific antigen (PSA) rise following radical prostatectomy (RP). Notably, the importance of lymph node dissection (LND) at the time of RP with regard to recurrence risk following sRT has not been previously determined. Therefore, we evaluated the association between nodal yield at RP and recurrence after sRT. We performed a multi-institutional review of men with a rising PSA after RP treated with sRT. Clinicopathologic variables were abstracted, and the associations between lymph node yield and biochemical (BCR) as well as clinical recurrence (CR) after sRT were assessed using multivariable Cox proportional hazards regression models. In total, 728 patients were identified; of these, 221 and 116 were diagnosed with BCR and CR, respectively, during a median follow-up of 8.4 (interquartile range: 4.2–11.2) yr. On multivariable analysis, the risk of BCR after sRT was inversely associated with the number of nodes resected at RP (hazards ratio [HR]: 0.98; 95% confidence interval [CI]: 0.96–0.99; p = 0.049). Increased extent of dissection was also independently associated with a decreased risk of CR after sRT (HR: 0.97; 95%CI: 0.94–0.99; p = 0.042). These data support the importance of an extensive LND at surgery and may be used in prognosis assessment when sRT is being considered. Patient summary: We found that patients who had increased number of lymph nodes resected at surgery had improved outcomes after the receipt of salvage radiation therapy. These findings support the use of the extended lymph node dissection at initial surgery and should serve to improve counseling among patients who require salvage radiation therapy.