Session: MP67: Prostate Cancer: Localized: Surgical Therapy III
MP67-11: Repeat Salvage Lymph Node Dissection for Recurrence of Prostate Cancer Using PSMA-Radioguidance Surgery (RGS) after prior Salvage Lymph Node Dissection with or without initial RGS-support
Martini-Klinik Prostate Cancer Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
Introduction: With the advances of molecular PSMA PET imaging, metastasis directed therapy for low-PSA, recurrent locoregional metastatic prostate cancer after initial radical prostatectomy (RP) becomes more feasible. After initial salvage surgery patients (pts) with good response consider a secondary salvage surgery in case of progression and again circumscript prostate cancer lesion(s) on imaging. However, the oncologic outcome and safety profile of repeat PSMA-targeted radioguided surgery (RGS) after prior RGS or “standard” salvage lymph node dissection (sLND) remains unknown. Methods: Within the prospectively collected clinical database of two tertiary care centers we identified 37 pts, who received a secondary RGS after prior sLND (n=21) or RGS (n=16) with or without prior pelvic radiation therapy between 2014 and 2021. Kaplan-Meier curves and uni-/multivariable Cox regression models were used to predict biochemical-recurrence free survival (BRFS) after the second salvage surgery. Histological correlation, time between first and second salvage surgery and Clavien-Dindo complications were evaluated. Results: Median age at second salvage surgery was 70 years (IQR: 62-74y, RGS-RGS) or 69 years (IQR: 65-70y, sLND-RGS). Preoperative median PSA was 0.66 ng/ml (IQR: 0.42-1.3 ng/ml, RGS-RGS) or 1.16 (IQR: 0.89-2.25 ng/ml, sLND-RGS). In the univariable Cox regression model, age (HR 1.06), pN1 at RP (HR 2.72), preoperative PSA (HR 1.16), number of lesions on PSMA PET (HR 2.14) and retroperitoneal localization (HR 3,93 for combined pelvic and retroperitoneal lesions) were statistically significant predictors for shorter BRFS in the whole cohort (p < 0.05). Time between first and second salvage surgery as well as the kind of first salvage surgery (RGS or sLND) were not statistically significant associated with an increased BRFS. Complete biochemical response (PSA < 0.2 ng/ml) was seen in 62.5%. One year after secondary salvage surgery 89.2% did not receive additional treatment. Rate for major complications (Clavien-Dindo >3a) was 14% (3 pts) in the sLND-RGS group. There was no major complication in the RGS-RGS group. Conclusions: In selected cases, repeat RGS might delay the need for systemic treatment, while offering a reasonable safety profile. Especially in young patients with one pelvic recurrence and low PSA, second salvage surgery using RGS seems reasonable independent of time from initial RP or first salvage surgery. Limitations are the retrospective evaluation, heterogenous sLND procedures (mainly done in external hospitals) and lack of long follow up data, as well as the small cohort. SOURCE OF Funding: None.
