68-Ga-PSMA-PET in lymph node staging in PSA recurrent prostate cancer-does the primary influence the result?

210Background: Prostate cancer is the most common cancer in western countries. 68Ga PSMA-PET is the most accurate tool to detect lymph node metastases even at low PSA values. Salvage lymph node dissection prolongs biochemical recurrent free survival, whereas salvage radical prostatectomy has the potential to achieve long term tumor control at least in node negative disease. We compared the diagnostic value of 68Ga-PSMA PET in patients with biochemical recurrence after radical prostatectomy an salvage radiotherapy (Group1) and in patients with local recurrence after radiotherapy (Group2) to evaluate the influence of the primary. Methods: We retrospectively reviewed 57 and 31 patients in Group I and II respectively. In Group I a salvage lymph node dissection was performed on the side of the positive PSMA-staining. In Group II an extended pelvic lymph node dissection was performed in addiction to a salvage radical prostatectomy. Sensitivity, Specificity, posisive and negative predictive value as well as accu...