Optimizing Unilateral Pelvic Lymph Node Dissection in the PSMA Era: Balancing Oncological Safety, Contralateral Involvement Risk, and Overtreatment in Prostate Cancer: A Multicenter Study of the Turkish Urooncology Association.

[OBJECTIVE] To evaluate the risk of contralateral lymph node involvement (LNI) and the feasibility of safely performing unilateral pelvic lymph node dissection (PLND) in unfavorable-intermediate and high-risk prostate cancer (PCa) patients with cN0 status on preoperative Ga-PSMA PET/CT, tumor involvement in single lobe, or dominant lobe involvement with worse tumor characteristics on biopsy.

[MATERIAL AND METHODS] In this retrospective multicenter study were analyzed 768 patients who underwent RP and bilateral extended-PLND. Patients with cN0 status on PSMA PET/CT and PI-RADS ≥ 3 lesions on multiparametric magnetic resonance imaging(mpMRI) were included. Tumor lobe (single/dominant-prostatic lobe) involvement and LNI status were recorded for all patients. The dominant lobe was determined based on higher ISUP grade group(GG), number and percentage of more positive cores, and more advanced features on MRI, respectively. LNI status was analyzed by tumor side and location. Statistical analysis included univariate and multivariate models to evaluate predictors of contralateral LNI.

[RESULTS] LNI was observed in 96(12.5%) of 768 patients, with 61(7.9%) having ipsilateral LNI and 35(4.6%) contralateral LNI with or without ipsilateral LNI. Patients with contralateral LNI had higher preoperative PSA, more frequent EAU high-risk classification, larger-index lesion diameter, higher ISUP GG on both the dominant and nondominant side, and a higher rate of positive percentages in the nondominant side (all P values < .05). Multivariate analysis identified preoperative PSA (HR 1.028, 95% Cl 1.001-1.057, P = .044), ISUP GG 2 (HR 4.325,95% Cl-1.620-14.374,P = .007) and ≥ ISUP-GG 3 (HR 14.004, 95% Cl 3.025-54.773, P < .001) on the nondominant side as independent predictors for contralateral LNI. The ROC-derived AUC for predicting contralateral LNI was 0.873, indicating good predictive accuracy.

[CONCLUSION] In cases where preoperative Ga-PSMA PET/CT indicates a negative LN status, contralateral PLND may not be necessary in intermediate-risk patients with negative biopsy or ISUP GG 1 tumor on the nondominant side.