PSMA-positive nodal recurrence in prostate cancer: Salvage radiotherapy is superior to salvage lymph node dissection in retrospective analysis

PURPOSE: This analysis compares salvage lymph node dissection (SLND) to salvage lymph node radiotherapy (SLNRT) of (68)Ga-PSMA PET-positive nodal recurrences after radical prostatectomy (RPE). METHODS: A total of 67 SLNRT and 33 SLND consecutive patients with pelvic and/or para-aortic nodal recurrences after RPE were retrospectively analyzed. Biochemical recurrence-free survival rates (bRFS; PSA <0.2 ng/mL) were calculated according to Kaplan–Meier and survival curves were compared using the log rank test. For multivariable analysis, binary logistic regression analysis was performed (p < 0.05). RESULTS: Median follow-up was 17 months (range, 6–53 months) in SLND patients and 31 months (range, 3–56 months) in SLNRT patients (p = 0.027). SLNRT patients had significantly more tumours of pT3 and pT4 category (82% vs. 67%; p = 0.006), pathologically involved lymph nodes (45% vs. 27%; p = 0.001) and positive surgical margins (54% vs. 12%; p = 0.001) at time of RPE than SLND patients. PSA persistence after RPE was significantly more frequently observed in the SLNRT cohort (73% vs. 27%; p = 0.001). There was no significant difference in the distribution of PET-positive lymph nodes. Median PSA before SLND was higher than before SLNRT (3.07 ng/ml vs. 1.3 ng/ml; p = 0.393). The 2‑year bRFS was significantly higher in the SLNRT vs. the SLND cohort (92% vs. 30%; p = 0.001) with lower rates of distant metastases (21% vs. 52%; p = 0.002) and secondary treatments (5% vs. 39%; p = 0.011) irrespective of ongoing androgen deprivation therapy at last contact. In multivariable analysis, SLNRT was significantly associated with prolonged bRFS (regression coefficient 1.436, hazard ratio 4.204, 95% CI 1.789–9.878; p = 0.001). CONCLUSION: Based on this retrospective study SLNRT might be the preferred treatment option for patients with nodal recurrence after previous RPE. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00066-020-01605-z) contains supplementary material, which is available to authorized users.