Despite growing evidence for bilateral pelvic radiotherapy (whole pelvis RT, WPRT) there is almost no data on unilateral RT (hemi pelvis RT, HPRT) in patients with nodal recurrent prostate cancer after prostatectomy. Nevertheless, in clinical practice HPRT is sometimes used with the intention to reduce side effects compared to WPRT. Prostate-specific membrane antigen positron emission tomography / computed tomography (PSMA-PET/CT) is currently the best imaging modality in this clinical situation. This analysis compares PSMA-PET/CT based WPRT and HPRT.
A propensity score matching was performed in a multi-institutional retrospective dataset of 273 patients treated with pelvic RT due to nodal recurrence (214 WPRT, 59 HPRT). In total, 102 patients (51 in each group) were included in the final analysis. Biochemical recurrence-free survival (BRFS) defined as prostate specific antigen (PSA) < post-RT nadir + 0.2ng/ml, metastasis-free survival (MFS) and nodal recurrence-free survival (NRFS) were calculated using the Kaplan-Meier method and compared using the log rank test.
Median follow-up was 29 months. After propensity matching, both groups were mostly well balanced. However, in the WPRT group there were still significantly more patients with additional local recurrences and biochemical persistence after prostatectomy. There were no significant differences between both groups in BRFS (p = .97), MFS (p = .43) and NRFS (p = .43). After two years, BRFS, MFS and NRFS were 61%, 86% and 88% in the WPRT group and 57%, 90% and 82% in the HPRT group, respectively. Application of a boost to lymph node metastases, a higher RT dose to the lymphatic pathways (> 50 Gy EQD2α/β=1.5 Gy) and concomitant androgen deprivation therapy (ADT) were significantly associated with longer BRFS in uni- and multivariate analysis.
Overall, this analysis presents the outcome of HPRT in nodal recurrent prostate cancer patients and shows that it can result in a similar oncologic outcome compared to WPRT. Nevertheless, patients in the WPRT may have been at a higher risk for progression due to some persistent imbalances between the groups. Therefore, further research should prospectively evaluate which subgroups of patients are suitable for HPRT and if HPRT leads to a clinically significant reduction in toxicity.
European journal of nuclear medicine and molecular imaging. 2024 Jun 28 [Epub ahead of print]
Christian Trapp, Daniel M Aebersold, Claus Belka, Jozefina Casuscelli, Louise Emmett, Chukwuka Eze, Stefano Fanti, Andrea Farolfi, Wolfgang Fendler, Anca-Ligia Grosu, Matthias Guckenberger, George Hruby, Simon Kirste, Stefan A Koerber, Stephanie Kroeze, Jan C Peeken, Paul Rogowski, Sophia Scharl, Mohamed Shelan, Simon K B Spohn, Iosif Strouthos, Lena Unterrainer, Marco Vogel, Thomas Wiegel, Constantinos Zamboglou, Nina-Sophie Schmidt-Hegemann
Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany. ., Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland., Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany., Department of Urology, University Hospital, LMU Munich, Munich, Germany., Department of Theranostics and Nuclear Medicine, St. Vincent's Hospital, Sydney, Australia., Nuclear Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy., Department of Nuclear Medicine, University Hospital,University of Essen, Essen, Germany., Department of Radiation Oncology, Medical Center , University of Freiburg, Freiburg, Germany., Department of Radiation Oncology, University Hospital, University of Zurich, Zurich, Switzerland., Department of Radiation Oncology, Royal North Shore Hospital, University of Sydney, Sydney, Australia., Department of Radiation Oncology, Barmherzige Brüder Hospital Regensburg, Regensburg, Germany., Deutsches Konsortium für Translationale Krebsforschung (DKTK), Partner Site Munich, Munich, Germany., Department of Radiation Oncology, University of Ulm, Ulm, Germany., Department of Radiation Oncology, German Oncology Center, European University Cyprus, Nicosia, Cyprus., Department of Nuclear Medicine, University Hospital, LMU Munich, Munich, Germany.