Preoperative 68Ga-PSMA PET/CT defines a subgroup of high-risk prostate cancer patients with favorable outcomes after radical prostatectomy and lymph node dissection

Background: High-risk prostate cancer is associated with adverse pathology and unfavorable outcomes after radical prostatectomy. ⁶⁸Ga-PSMA PET/CT is more accurate than conventional imaging for preoperative staging. We aimed to evaluate whether lymph node involvement on ⁶⁸Ga-PSMA PET/CT prior to radical prostatectomy in patients with high-risk prostate cancer is associated with worse short-term oncologic outcomes. Methods: We retrospectively reviewed 149 patients with high-risk localized or locoregional prostate cancer who underwent ⁶⁸Ga-PSMA PET/CT prior to radical prostatectomy between 2015 and 2020. None of the patients received neoadjuvant or adjuvant treatment. The study endpoints were PSA persistence and biochemical recurrence. Logistic regression models were used to identify preoperative predictors of PSA persistence. Kaplan–Meier analyses were used to estimate biochemical recurrence-free survival. Results: Of 149 identified patients, 19 (13%) were found to have lymph node involvement on preoperative ⁶⁸Ga-PSMA PET/CT. The sensitivity, specificity, and accuracy of ⁶⁸Ga-PSMA PET/CT for identifying pathologic lymph node involvement were 68%, 95%, and 92%, respectively. PSA persistence rate was lower among patients with PET-negative lymph nodes than those with PET-positive nodes (15 vs. 84%, p< 0.001). Positive nodes on imaging (OR = 41.03, p< 0.001) and clinical T2c–T3 stage (OR = 6.96, p= 0.002) were associated with PSA persistence on multivariable analysis. Among patients with PET-negative nodes the 1- and 2-year biochemical recurrence-free survival rates were 87% and 76%, respectively. Conclusions: Preoperative staging with ⁶⁸Ga-PSMA PET/CT may identify a subgroup of high-risk prostate cancer patients with favorable short-term outcomes after radical prostatectomy without adjuvant treatment. Future studies will evaluate whether these results are sustained during long-term follow-up.