Bilateral Versus Unilateral Lymph Node Dissection in High-Risk Prostate Cancer (BALANCE)

Inclusion Criteria: * Male patients aged 18 years or older * Histologically confirmed unilateral high-risk localized prostate cancer, defined by at least one of the following: ISUP Grade Group 4 or 5; suspicion of at least cT3a disease on multiparametric MRI and/or PSMA PET; or PSA greater than or equal to 20 ng/mL with a unilateral index lesion * Unilateral features of the index lesion defined by biopsy, multiparametric MRI, and PSMA PET * No PSMA PET-positive pelvic lymph nodes contralateral to the dominant side of the prostate cancer * No significant contralateral PSMA uptake on the non-dominant side, defined as lesions with PRIMARY score 3 to 5 * No contralateral index lesion on multiparametric MRI subsequently confirmed by prostate biopsy * No high-risk histology on the side contralateral to the dominant lesion, including ISUP Grade Group greater than 3 or unconventional prostate cancer histology * No frank extracapsular invasion or seminal vesicle invasion on the contralateral side * Up to two positive systematic cores with unfavorable intermediate-risk disease or up to four with favorable intermediate-risk disease are allowed on the contralateral side * A maximum of two pelvic PSMA-positive lymph nodes allowed on the dominant side * Clinically localized disease, defined as less than cT4 on multiparametric MRI and no distant metastases, including no retroperitoneal lymph nodes on PSMA PET * Life expectancy greater than 10 years according to physician judgment * Scheduled for robot-assisted radical prostatectomy and fit for surgery * Written informed consent provided Exclusion Criteria: * Any prostate cancer treatment prior to prostatectomy, including androgen deprivation therapy, neoadjuvant chemotherapy, radiotherapy, or focal ablative therapy * Prior active treatment for prostate cancer * Contralateral ISUP Grade Group 4 to 5 prostate cancer * Contralateral ISUP Grade Group 2 in more than 4 positive cores or ISUP Grade Group 3 in more than 2 positive cores * Contralateral cT3 disease on multiparametric MRI * N1 or M1 disease on PSMA PET or multiparametric MRI, except for up to two positive pelvic lymph nodes on the dominant side * No systematic prostate biopsies performed, with a minimum of 10 cores, and targeted biopsies when a target lesion is present * Other active malignancy * Contraindication to multiparametric MRI and/or PSMA PET * Inability to provide written informed consent * Age younger than 18 years * ASA score greater than 3 * Any contraindication to pelvic lymph node dissection * Severe psychiatric disease * Inadequate hematologic and/or coagulation function * Active infection * Any other serious medical, psychiatric, psychological, familial, or geographic condition that, in the judgment of the investigator, may interfere with staging, treatment, follow-up, compliance, or increase treatment-related risk * Patients with prior malignancy treated with curative intent are eligible only with mandatory approval by the local multidisciplinary tumor board