Salvage radiation therapy (SRT) is a recommended treatment option for biochemical recurrence after radical prostatectomy (RP). However, its effectiveness may be limited to specific categories of patients.
We aimed to identify the optimal candidates for early SRT after RP.
The study included 925 node-negative patients treated with SRT after RP at seven institutions. Patients received SRT for either prostate-specific antigen (PSA) rising, or PSA persistence after RP that was defined as PSA level ≥0.1 ng/ml at 1 mo after surgery. All patients received local radiation to the prostate and seminal vesicle bed.
The primary outcome measured was distant metastasis after SRT. Regression tree analysis was used to develop a risk-stratification tool. Multivariable Cox regression analysis and nonparametric curve fitting methods were used to explore the relationship between PSA level at SRT and the probability of metastasis-free survival at 8 yr.
At a median follow-up of 8.0 yr, 130 patients developed distant metastasis. At multivariable analysis, pre-SRT PSA level was significantly associated with distant metastasis (hazard ratio: 1.06, p<0.0001). However, when patients were stratified into five risk groups using regression tree analysis (area under the curve: 85%), early SRT administration provided better metastasis-free survival in three groups only: (1) low risk: undetectable PSA after RP, Gleason score ≤7, and tumour stage ≥pT3b, (2) intermediate risk: undetectable PSA after RP with Gleason score ≥8, (3) high risk: PSA persistence after RP with Gleason score ≤7.
We developed an accurate risk stratification tool to facilitate the individualised recommendation for early SRT based on prostate cancer characteristics. Early SRT proved to be beneficial only in selected groups of patients who are more likely to be affected by clinically significant but not yet systemic recurrence at the time of salvage treatment administration.
In patients affected by prostate cancer recurrence after radical prostatectomy, the early administration of salvage radiation therapy is beneficial only for selected subgroups of patients. In this study, these groups of patients were identified.
European urology. 2017 Aug 02 [Epub ahead of print]
Nicola Fossati, R Jeffrey Karnes, Michele Colicchia, Stephen A Boorjian, Alberto Bossi, Thomas Seisen, Nadia Di Muzio, Cesare Cozzarini, Barbara Noris Chiorda, Claudio Fiorino, Giorgio Gandaglia, Paolo Dell'Oglio, Shahrokh F Shariat, Gregor Goldner, Steven Joniau, Antonino Battaglia, Karin Haustermans, Gert De Meerleer, Valérie Fonteyne, Piet Ost, Hendrik Van Poppel, Thomas Wiegel, Francesco Montorsi, Alberto Briganti
Division of Oncology/Unit of Urology, URI, IRCCS Ospedale San Raffaele, Milan, Italy. Electronic address: ., Department of Urology, Mayo Clinic, Rochester, MN, USA., Department of Radiation Oncology, Gustave Roussy Institute, Villejuif, France., Department of Radiotherapy, IRCCS Ospedale San Raffaele, Milan, Italy., Department of Medical Physics, IRCCS Ospedale San Raffaele, Milan, Italy., Division of Oncology/Unit of Urology, URI, IRCCS Ospedale San Raffaele, Milan, Italy., Department of Urology, Medical University of Vienna, Vienna, Austria., Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria., Department of Urology, University Hospitals Leuven, Leuven, Belgium., Department of Radiotherapy, University Hospitals Leuven, Leuven, Belgium., Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium., Department of Radiation Oncology, University Hospital Ulm, Ulm, Germany.