Session: MP67: Prostate Cancer: Localized: Surgical Therapy III
MP67-03: Identifying the Optimal Candidates for a Super-extended Staging Pelvic Lymph-Node Dissection in Prostate Cancer Patients Treated in the PET-PSMA Era. Results from a Multi-institutional Series.
Introduction: An extended pelvic lymph node dissection (ePLND) represents the gold standard for nodal staging in prostate cancer (PCa). However, patients with higher risk of lymph-node invasion (LNI) at final pathology might benefit from a staging super-extended PLND (sePLND) given the risk of nodal metastases in the common iliac and/or pre-sacral sites. However, these results have been obtained in pre-PSMA era. We hypothesized that PET-PSMA findings might improve the identification of candidates for a sePLND. Methods: We relied on 662 PCa patients with PET-PSMA performed before RP treated at 9 referral centres between 2016 and 2022. Patients receiving neoadjuvant treatments were excluded. We identified 57 men with PET-PSMA detected suspicious nodal pelvic lesions (cN1) who underwent sePLND at the time of radical prostatectomy (RP) with complete data. The sePLND was defined as a LND including the presacral and common iliac nodal landing sites. The outcome was LNI in the common iliac and/or pre-sacral stations. Preoperative risk of LNI was calculated using the Briganti nomogram. Uni- and multivariable logistic regression (MLR) models tested the association between the number of positive nodes at PET-PSMA (1-2 vs >2) and common iliac and/or pre-sacral positive nodes after accounting for baseline risk of LNI. Results: Overall, 38 (66%) patients exhibited pN1 disease while 10 (18%) had LNI in the common iliac or pre-sacral landing sites. The median preoperative risk of LNI and the number of positive nodes at PET-PSMA were 23% (9-40%) and 2 (1-3). After stratification according to the preoperative LNI risk, the positivity rates in the common iliac and/or pre-sacral nodes were 15 and 22% in patients with an LNI risk =30% and >30%. When stratifying according to the number of positive nodes at PET-PSMA, the rates of LNI in the common iliac and/or presacral stations were 6 and 35%, in patients with 1-2 and >2 positive nodes at imaging. In MLR models, the number of positive nodes at PET-PSMA (namely >2 vs 1-2; OR: 7.81, p=0.019) achieved independent predictor status for LNI in the common iliac and/or pre-sacral nodal regions after adjusting for the risk of LNI Conclusions: The extent of nodal burden at PET-PSMA was associated with higher risk of LNI in the common iliac and/or pre-sacral landing sites. Patients with >2 suspicious lymph nodes at PET-PSMA might are those who could benefit the most from a staging sePLND regardless of the baseline risk of LNI SOURCE OF Funding: None
