Introduction

The management of patients with biochemical recurrence (BCR) after curative treatment for prostate cancer (PCa) remains controversial. Our aim was to investigate if preoperative 68Ga-PSMA-HBED-CC (68Ga-PSMA) positron emission tomography / computed tomography (PET/CT) improves biochemical response (BR) in patients undergoing salvage lymph node dissection (sLND) for recurrent PCa while evaluating complications, predictors and overall survival rates.

Methods

Between 2005 and 2016 we performed sLND in 104 PCa patients diagnosed with nodal recurrence on either 18F-fluoroethylcholine (18F-FEC) or 68Ga-PSMA PET/CT after radical prostatectomy (RP). Surgical complications according to Clavien-Dindo classification, and BR, BCR after BR, clinical recurrence (CR), and cancer-specific survival (CSS) were evaluated. Survival rates were assessed and logistic regression was used to determine predictors of BR and CR after sLND.

Results

Mean follow-up after sLND was 45.7 ± 30.4 months. Mean patient age and prostate-specific antigen (PSA) at sLND were 64.7 ± 7.0 years and 8.2 ± 14.8 ng/mL. 12.7%, 17.6% and 53.9% of patients underwent radiotherapy (RT), androgen deprivation therapy (ADT) and both RT + ADT after RP. Mean number of lymph nodes (LNs) removed was 17.1 ± 15.0 per patient at sLND; mean number of positive LNs was 5.2 ± 7.4 per patient. 29.8% of patients developed complete BR (cBR) (PSA <0.2 ng/mL), and 56.7% of partial BR (PSA postoperative < PSA preoperative). Patients diagnosed with preoperative 68Ga-PSMA PET/CT showed a significantly higher rate of cBR after sLND compared to 18F-FEC PET/CT (45.7 vs. 21.7%, p=0.040). BCR after cBR was detected in 71.0% of patients, and CR on PET/CT occurred in 70.2% of patients during follow-up. The 5-year BCR-free, CR-free and CSS rates were 6.2%, 26.0%, and 82.8%, respectively. At multivariate logistic regression, continuous PSA (p=0.031) and choice of PET tracer (p=0.048) were independent predictors of cBR. Overall rate of Clavien-Dindo Grade III complications was low (4.8%).

Conclusions

sLND may be safely performed with low complication rates. While preoperative staging with 68Ga-PSMA seems superior to 18F-FEC PET/CT, only a limited number of patients developed cBR after surgery. The majority of patients progressed to BCR and CR after cBR. The real clinical benefit of sLND for nodal recurrence after RP with regard to improved survival needs to be assessed in future prospective randomized trials.

Funding

None.