Introduction: The role of local therapies including radical prostatectomy (RP) in prostate cancer (PCa) patients with clinical lymphadenopathies at PET/CT has been scarcely explored. Limited data is available to identify men more likely to have non-localized disease and who may benefit from multi-modal approaches. We assessed predictors of PSA persistence in surgically managed PCa patients with clinical lymphadenopathies at PET/CT by integrating clinical, magnetic resonance imaging (MRI) and PET/CT parameters.
Methods: We identified 93 men treated with RP and extended lymph node dissection with pelvic or retroperitoneal lymphadenopathies at choline (n = 46, 49%) or PSMA (n = 47, 51%) PET/CT between 2010 and 2021 at four referral centers. The study outcome was PSA persistence, defined as a first PSA = 0.1 ng/ml after RP. Multivariable logistic regression tested predictors of PSA persistence. Covariates were biopsy ISUP grade group (1-3 vs 4-5), MRI stage (organ-confined disease [OC] vs extracapsular extension [ECE]) and number of positive spots at PET/CT. Regression tree analyses stratified patients into risk groups based on their preoperative characteristics.
Results: Median number of positive spots at PET/CT was 2 (IQR 1-3). Overall, 70 (75%) and 23 (25%) men had biopsy ISUP grade 4-5 and ECE at MRI. 42 (45%) experienced PSA persistence. At multivariable analyses, ISUP grade 4-5 was the strongest predictor of PSA persistence (OR 4.12; p=0.001). At regression tree, patients were stratified in four risk group according to ISUP grade, number of positive spots and MRI stage (Fig. 1). The model had a good discrimination (AUC 77%). Clinical N1 patients with ISUP grade 4-5 and ECE at MRI had a rate of 75% of PSA persistence regardless of the number of positive spots at PET/CT, thus being likely have upfront systemic disease.
Conclusions: PSA persistence is non-negligible in patients with a positive lymphnodes at preoperative PET/CT. Patients with ISUP grade 1-3, as well as patients with ISUP grade 4-5, OC disease at MRI and 1-2 positive spots at PET/CT are those where RP may achieve good oncological outcomes. Conversely, patients with high ISUP grade and ECE at MRI should be considered for integrated multi-modal approaches including systemic therapies.