Salvage radiotherapy is effective in patients with PSMA-PET-negative biochemical recurrence- results of a retrospective study

• Published in: Radiotherapy and oncology Vol. 184; p. 109678
• Main Authors: Scharl, Sophia, Zamboglou, Constantinos, Strouthos, Iosif, Farolfi, Andrea, Serani, Francesca, Lanzafame, Helena, Giuseppe Morganti, Alessio, Trapp, Christian, Koerber, Stefan A., Debus, Jürgen, Peeken, Jan C., Vogel, Marco M.E., Vrachimis, Alexis, Spohn, Simon K.B., Ruf, Juri, Grosu, Anca-Ligia, Ceci, Francesco, Fendler, Wolfgang P., Bartenstein, Peter, Kroeze, Stephanie G.C., Guckenberger, Matthias, Krafcsik, Manuel, Klopscheck, Christina, Fanti, Stefano, Hruby, George, Emmett, Louise, Belka, Claus, Stief, Christian, Schmidt-Hegemann, Nina-Sophie, Henkenberens, Christoph, Mayer, Benjamin, Miksch, Jonathan, Shelan, Mohamed, Aebersold, Daniel M., Thamm, Reinhard, Wiegel, Thomas
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01.07.2023
• Subjects: Androgen Antagonists; Gallium Radioisotopes; Humans; Lymphatic Metastasis; Male; Neoplasm Recurrence, Local - pathology; PET negative; Positron Emission Tomography Computed Tomography - methods; Positron-Emission Tomography; Prostate cancer; Prostate-Specific Antigen; Prostatectomy - methods; Prostatic Neoplasms - diagnostic imaging; Prostatic Neoplasms - pathology; Prostatic Neoplasms - radiotherapy; PSMA PET-CT; Retrospective Studies; Salvage radiotherapy; Salvage Therapy - methods; Salvage radiotherapy; PET negative; Prostate cancer; PSMA PET-CT
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2023.109678

•Salvage radiotherapy effectively treats biochemical recurrence of prostate cancer regardless of PET imaging result.•Salvage radiotherapy should be initiated in a timely manner in patients without PET correlate.•Biochemical progression-free survival significantly depended on age and prostate-specific antigen-doubling time.•In patients with locally positive lesions, pathology and dose to the fossa influenced biochemical progression-free survival. The present study aimed to assess whether SRT to the prostatic fossa should be initiated in a timely manner after detecting biochemical recurrence (BR) in patients with prostate cancer, when no correlate was identified with prostate-specific membrane antigen positron emission tomography (PSMA-PET). This retrospective, multicenter analysis included 1222 patients referred for PSMA-PET after a radical prostatectomy due to BR. Exclusion criteria were: pathological lymph node metastases, prostate-specific antigen (PSA) persistence, distant or lymph node metastases, nodal irradiation, and androgen deprivation therapy (ADT). This led to a cohort of 341 patients. Biochemical progression-free survival (BPFS) was the primary study endpoint. The median follow-up was 28.0 months. The 3-year BPFS was 71.6% in PET-negative cases and 80.8% in locally PET-positive cases. This difference was significant in univariate (p = 0.019), but not multivariate analyses (p = 0.366, HR: 1.46, 95%CI: 0.64–3.32). The 3-year BPFS in PET-negative cases was significantly influenced by age (p = 0.005), initial pT3/4 (p < 0.001), pathology scores (ISUP) ≥ 3 (p = 0.026), and doses to fossa > 70 Gy (p = 0.027) in univariate analyses. In multivariate analyses, only age (HR: 1.096, 95%CI: 1.023–1.175, p = 0.009) and PSA-doubling time (HR: 0.339, 95%CI: 0.139–0.826, p = 0.017) remained significant. To our best knowledge, this study provided the largest SRT analysis in patients without ADT that were lymph node-negative on PSMA-PET. A multivariate analysis showed no significant difference in BPFS between locally PET-positive and PET-negative cases. These results supported the current EAU recommendation to initiate SRT in a timely manner after detecting BR in PET negative patients.