Observation With or Without Subsequent Salvage Therapy for Pathologically Node-positive Prostate Cancer With Negative Conventional Imaging: Results From a Large Multicenter Cohort

Initial observation is a feasible option for management of patients with preoperative node-negative status on conventional imaging and positive nodes at radical prostatectomy in the absence of worse disease features. More than 10% of patients with negative clinical metastatic status (cN0M0) on conventional imaging for prostate cancer (PCa) harbor lymph node involvement (pN+) at final pathology following radical prostatectomy (RP) and lymphadenectomy. Our aim was to assess outcomes of initial observation for cN0M0 pN+ PCa and identify prognostic factors that may help in clinical decision-making. We performed a retrospective multicenter study of patients with cN0M0 PCa on conventional imaging (computed tomography and/or magnetic resonance imaging, and a bone scan) who were found to have pN+ disease at RP between 2000 and 2021. Biochemical recurrence (BCR) and systemic progression/recurrence were the primary outcomes. Kaplan-Meier curves and Cox proportional hazards model were used for survival and multivariate analysis. A total of 469 men were included in this retrospective multicenter trial. Median prostate-specific antigen (PSA) was 10.1 ng/ml (interquartile range [IQR] 6.6–18.0). Among these patients, 56% had grade group ≥4, 53.7% had stage ≥pT3b, 42.6% had positive margins, and 19.6% had PSA persistence. The median number of positive nodes and of nodes removed were 1 (IQR 1–3) and 20 (14–28), respectively. At median follow-up of 41 mo, 48.5% experienced BCR. The 5-yr BCR-free survival rate was 31.7% (95% confidence interval [CI] 26.33–37.1%). Salvage treatments were needed in 211 patients and included radiotherapy (RT; n = 53), RT + androgen deprivation therapy (ADT; n = 88), ADT alone (n = 68), and salvage lymphadenectomy (n = 2). The 5-yr estimated survival rates were 66.3% (95% CI 60.4–72.1) for metastasis-free survival, 97.7% (95% CI 95.5–99.8%) for cancer-specific survival, and 95.3% (95% CI 92.4–98.1%) for overall survival. On multivariable analysis, PSA persistence was an independent predictor of BCR (odds ratio [OR] 51.8, 95% CI 12.2–219.2), exit from observation (OR 8.5, 95% CI 4.4–16.5), and systemic progression (OR 3.0, 95% CI 1.771–4.971). Initial observation in the management of pN+ cN0M0 PCa is feasible and has excellent survival rates in the intermediate term. Patients with worse disease features, especially PSA persistence, have a higher likelihood of recurrence and progression and may be candidates for more aggressive upfront management.