the CYGNUS study aims to assess both toxicity and efficacy of stereotactic body radiotherapy (SBRT) performed as salvage approach for pelvic nodal metachronous oligorecurrent (PNMOR) hormone-sensitive prostate cancer (PCa), in previously irradiated territory.
Inclusion criteria were histologically history of proven PCa, locally treated with a radical intent and a biochemical relapse as defined by the European Association of Urology guidelines. All patients had a radiological suspicion of PNMOR, defined as a recurrence occurring in pelvic nodal areas with up to 5 suspect lymph nodes. Reirradiation was defined according to the ESTRO-EORTC consensus on re-irradiation as an irradiation with a geometrical overlap with a previous course of RT.
A total of 155 re-irradiation among 150 patients relapsing on 192 nodal sites were retrospectively included, from 13 French centers. The majority of patients (80.7%) received radical prostatectomy as primary treatment. After a median follow-up of 30.5 months, late grade 2 and grade 3 GI and GU toxicity occurred in 1.9%, 0% and 7.1% and 2.6% of the cases, respectively. The 2-year radiological progression-free survival (rPFS) reached respectively 44.6% (95% CI: 36.2% - 55%).. The 2-year androgen deprivation therapy-free survival (ADT-FS) reached 52.6% (95% CI: 42% - 65.9%). Previous ADT prescription was predictive in multivariable analysis of both rPFS (HR:2.02, 95%CI: 1.25-3.26, p=0.004) and ADT-FS (HR:2.49, 95%CI: 1.28-4.72, p=0.006). A PSA doubling time <5months correlated with a shorter ADT-FS (AUC 0.629, p= 0.014).
The CYGNUS retrospective study suggests that reirradiation with SBRT for PNMOR is associated with a low rate of toxicity. However, further data with plan summation and longer follow-up are needed to confirm these findings.
International journal of radiation oncology, biology, physics. 2026 Mar 19 [Epub ahead of print]
Ewen Anger, Stephane Supiot, Quentin Josset, David Pasquier, Loïg Vaugier, François-Georges Riet, Yoann Pointreau, Amandine Ruffier, Geneviève Loos, Mario Terlizzi, Pierre Blanchard, Etienne Martin, Paul Sargos, Marie Guerni, Ulrike Schick, Guillaume Bera, Julien Roman, Igor Latorzeff, Gilles Créhange, Joël Castelli, Anais Barateau, Renaud De Crevoisier, Luca Nicosia, Jennifer Le Guévelou
Department of Radiotherapy, Centre Eugène Marquis, Rennes, France., Department of Radiation Oncology, Institut de Cancérologie de l'Ouest, Nantes, St-Herblain, France., Department of Radiation Oncology, Institut de Cancérologie de l'Ouest, Angers, France., Academic Radiation Oncology Department, Centre Oscar Lambret, Lille, France., Department of Radiation Oncology, Institut de Cancérologie Régional Bretillien, Saint Grégoire, France., Department of Radiation Oncology, Centre Jean Bernard, Le Mans, France., Department of Radiation Oncology, Centre Jean Perrin, Clermont-Ferrand, France., Department of Radiation Oncology, Gustave Roussy, Université Paris Saclay, Villejuif, France., Department of Radiation Oncology, Georges-Francois Leclerc Cancer Center, Dijon, France., Department of Radiation Oncology, Institut Bergonié, Bordeaux, France., Department of Radiation Oncology, University Hospital, Brest, France., Department of Radiation Oncology, Scorff Hospital, Lorient, France., Department of Radiation Oncology, Centre Saint Yves, Vannes, France., Department of Radiation Oncology, Clinique Pasteur, Toulouse, France., Department of Radiation Oncology, institut Curie, 26, rue d'Ulm, 75005 Paris, France., Department of Radiotherapy, Centre Eugène Marquis, Rennes, France; LTSI, Universite de Rennes 1, Rennes, France., Department of Radiation Oncology, IRCCS Sacro Cuore Don Calabria, Negrar Di Valpoticella, Italy., Department of Radiotherapy, Centre Eugène Marquis, Rennes, France; University of Medicine, Department of radiation oncology, CHRU Tours, Tours, France. Electronic address: .
PubMed http://www.ncbi.nlm.nih.gov/pubmed/41864432