Targeted salvage lymphadenectomy in patients treated with radical prostatectomy with biochemical recurrence: complete biochemical response without adjuvant therapy in patients with low volume lymph node recurrence over a long-term follow-up

BACKGROUND: Choline positron emission tomography/computed tomography (PET/CT) represents an option in restaging of prostate cancer patients with disease relapse after local treatment. The present study assess whether salvage resection of lymph node metastases detected on choline PET/CT imaging in prostate cancer patients with biochemical recurrence after radical prostatectomy can result in a long-term complete biochemical remission, without adjuvant therapy. METHODS: We analysed 13 patients with prostate specific antigen (PSA) recurrence (PSA median 1.64 ng/ml, range 0.5-9.55) after radical prostatectomy and suspicious lymph nodes (median 1; range 1–3) detected on [11C]choline and [18F]fluoroethylcholine PET/CT scans. An open salvage lymphadenectomy of positive lymph nodes in a PET/CT scan and nearby lymph nodes was carried out. We examined PSA outcome without adjuvant therapy; defined complete biochemical remission as PSA <0.01 ng/ml. Histological and PET/CT findings were compared. RESULTS: Ten of 11 patients with histologically confirmed lymph node metastases showed a PSA response. Three of ten patients with single lymph node metastases had a complete biochemical remission (median follow-up 72 months, range 31.0-83). In five cases with single lymph node metastasis PSA decreased <0.02 ng/ml. Histologically confirmed 13 of 16 metastasis suspicious lymph nodes. No lymph node metastases were detected in two patients. All of the additionally removed 30 lymph nodes were correctly negative. CONCLUSIONS: This is the first confirmation of a complete biochemical remission after PET/CT guided secondary resection of a single lymph node metastasis in prostate cancer patients with biochemical recurrence after radical prostatectomy, over the long-term (>6.5 years), without adjuvant therapy. In order to improve these promising results, longer-term studies with more patients are required.