Can contralateral lymph-node metastases be ruled out in prostate cancer patients with only unilaterally positive prostate biopsy?

PURPOSE: Our study evaluated the diagnostic benefits of bilateral pelvic lymphadenectomy in prostate cancer patients with unilaterally positive prostate biopsy. METHODS: Our retrospective analysis included clinical, surgical, and histopathological data of 440 prostate cancer patients treated with radical prostatectomy and bilateral sentinel-guided and risk-adapted complementary extended pelvic lymphadenectomy at our hospital between 2015 and 2022. We performed multiparametric logistic regression analysis to identify the most relevant predictive factors for detecting lymph-node metastasis in this group of patients. RESULTS: Overall, 373 patients (85%) had histopathologically bilateral tumours and 45 (10%) pN1 status, of which 22 (49%) also had lymph-node metastasis contralateral to the side of the positive prostate biopsy. In two patients with confirmed unilateral disease in prostatectomy specimens, bilateral lymph-node metastases were observed. Eight pN1 patients would have been missed by unilateral pelvic lymphadenectomy, resulting in a false-negative rate of 18%, 82% sensitivity, and 98% accuracy. Clinical tumour category, International Society of Urological Pathology grade, and percentage of prostate biopsy cores that are positive, as well as number of dissected lymph nodes contralateral to positive prostate biopsy, were determined as the most relevant predictive factors for detecting lymph-node metastasis. Our analysis was limited by its retrospective nature as well as by the fact that 80% of the patients did not receive MRI-targeted biopsy. CONCLUSION: Our study highlights the diagnostic value of bilateral pelvic lymphadenectomy and the need for careful planning in surgery for prostate cancer patients with unilaterally positive prostate biopsy. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10147-023-02407-w.