Safety and efficiency of repeat salvage lymph node dissection for recurrence of prostate cancer using PSMA-radioguided surgery (RGS) after prior salvage lymph node dissection with or without initial RGS support

Background and objective Metastasis-directed therapy is a feasible option for low PSA, recurrent locoregional metastatic prostate cancer.

After initial salvage surgery, patients with good response might consider a repeat salvage surgery in case of recurrent, isolated, and PSMA-positive metastases.

This analysis aimed to evaluate the oncological outcome and safety of repeat PSMA-targeted radioguided surgery (RGS) after either prior RGS or “standard” salvage lymph node dissection (SLND).

Materials and methods We identified 37 patients undergoing repeat RGS after prior SLND ( n  = 21) (SLND-RGS) or prior RGS ( n  = 16) (RGS-RGS) between 2014 and 2021 after initial radical prostatectomy with or without pelvic radiation therapy at two German tertiary referral centers.

Kaplan–Meier analyses and uni-/multivariable Cox regression models were used to investigate factors associated with biochemical recurrence-free survival (BRFS) and treatment-free survival (TFS) after repeat salvage surgery.

Results and limitations Complete Biochemical Response (cBR, PSA < 0.2 ng/ml) was observed in 20/32 patients (5 NA).

Median overall BRFS [95% confidence interval (CI)] after repeat salvage surgery was 10.8 months (mo) (5.3–22).

On multivariable regression, only age (HR 1.09, 95% CI 1.01–1.17) and preoperative PSA (HR 1.23, 95% CI 1.01–1.50) were associated with shorter BRFS, although PSA (HR 1.16, 95% CI 0.99–1.36) did not achieve significant predictor status in univariable analysis before ( p value = 0.07).

Overall, one year after second salvage surgery, 89% of the patients (number at risk: 19) did not receive additional treatment and median TFS was not reached.

Clavien–Dindo grade > 3a complications were observed in 8% (3/37 patients).

Limitations are the retrospective evaluation, heterogeneous SLND procedures, lack of long-term follow-up data, and small cohort size.

Conclusion In this study, repeat RGS was safe and provided clinically meaningful biochemical recurrence- and treatment-free intervals for selected cases.

Patients having low preoperative PSA seemed to benefit most of repeat RGS, irrespective of prior SLND or RGS or the time from initial RP/first salvage surgery.