Biochemical Response of <0.1 ng/ml Predicts Therapy-free Survival of Prostate Cancer Patients following Prostate-specific Membrane Antigen–targeted Salvage Surgery

BackgroundIn a subset of patients with oligorecurrent prostate cancer (PCa), salvage surgery with prostate-specific membrane antigen (PSMA) radioguided surgery (PSMA-RGS) seems to be of value.ObjectiveTo evaluate whether a lower level of postoperative prostate-specific antigen (PSA; 0.2 ng/ml. Kaplan-Meier and multivariable Cox regression models evaluated TFS according to PSA response.Results and limitationsAmong 553 patients assessed, 522 (94%) had metastatic soft tissue lesions removed during PSMA-RGS. At 2–16 wk after PSMA-RGS, 192, 62, and 190 patients achieved PSA levels of 0.2 ng/ml, respectively. At 2 yr of follow-up, TFS rate was 81.1% versus 56.1% versus 43.1% (p 0.2 ng/ml. In multivariable analyses, PSA levels of 0.1–0.2 ng/ml (hazard ratio HR: 1.9, confidence interval CI: 1.1–3.1) and ≥0.2 ng/ml (HR: 3.2, CI: 2.2–4.6, p < 0.001) independently predicted the need for additional therapy after PSMA-RGS. The main limitation is the lack of a control group.ConclusionsFor patients after salvage PSMA-RGS, a lower biochemical response (PSA <0.1 ng/ml) seems to predict longer TFS. This insight may help in counseling patients postoperatively as well as guiding the timely selection of additional therapy.Patient summaryWe studied what happened to prostate cancer patients in three European centers who had salvage surgery using a special method called prostate-specific membrane antigen–targeted radioguidance. We found that patients who had low prostate-specific antigen levels soon after surgery were less likely to need further treatment for a longer time.