Repeated stereotactic body radiotherapy for oligometastatic prostate cancer recurrence

Abstract

PurposeTo assess the outcome of prostate cancer (PCa) patients diagnosed with oligometastatic disease at recurrence and treated with stereotactic body radiotherapy (SBRT).MethodsNon-castrate patients with up to 3 synchronous metastases (bone and/or lymph nodes) diagnosed on positron emission tomography - computed tomography, following biochemical recurrence after local curative treatment, were treated with (repeated) SBRT to a dose of 50 Gy in 10 fractions or 30 Gy in 3 fractions. Androgen deprivation therapy-free survival (ADT-FS) defined as the time interval between the first day of SBRT and the initiation of ADT was the primary endpoint. ADT was initiated if more than 3 metastases were detected during follow-up even when patients were still asymptomatic. Secondary endpoints were local control, progression free survival (PFS) and toxicity. Toxicity was scored using the Common Terminology Criteria for Adverse Events.ResultsWith a median follow-up from time of SBRT of 2 years, we treated 50 patients with 70 metastatic lesions with a local control rate of 100%. The primary involved metastatic sites were lymph nodes (54%), bone (44%), and viscera (2%). The median PFS was 19 mo (95% CI: 13–25 mo) with 75% of recurring patients having ≤3 metastases. A 2nd and 3rd course of SBRT was delivered in 19 and 6 patients respectively. This results in a median ADT-FS of 25 months (20–30 mo). On univariate analysis, only a short PSA doubling time was a significant predictor for both PFS (HR: 0.90, 95% CI: 0.82 – 0.99) and ADT-FS (HR: 0.83; 95% CI: 0.71 – 0.97). Ten patients (20%) developed toxicity following treatment, which was classified as grade I in 7 and grade II in 3 patients.ConclusionRepeated SBRT for oligometastatic prostate cancer postpones palliative androgen deprivation therapy with 2 years without grade III toxicity.

CyberKnife stereotactic radiosurgery and stereotactic ablative radiation therapy of patients with prostate cancer bone metastases.

“…In their group (42/124 patients with prostate cancer) they found that irradiation to the single dose of 23-24Gy resulted in better local control of the lesions (2-year LC of 82% in whole group) although no correlation between the dose and LC was observed in prostate cancer group [12]. Very good results were also published by Muacevic et al [13,14,16]. Results obtained in our group are comparable to those reported in literature.…”

“…Also other researchers observed a decrease in PSA concentration during follow-up [11,13,14,17]. PSA concentration at last control was lower in patients with PSA below 20 ng/ml at the time of metastasis detection and based on data of other researchers similar observations can be made [11].…”

“…Muacevic A et al reported OS of 80% after median time of follow-up of 10.2 months [13]. Decaestecker K et al treated 50 patients with oligometastatic prostate cancer (44% bone metastases) and reported 2-year OS of 96% [14]. Also in our group OS was better than reported by Singh D. et al which suggest that use of SRS/SABR can result in prolongation of patients life despite other treatment options used [3].…”

Stereotactic Ablative Body Radiotherapy for the Treatment of Spinal Oligometastases

“…Decaestecker et al performed a study of 50 patients with prostate primaries, with three or fewer metastatic lesions, all treated with SABR [19]. Multiple sites were treated including lymph nodes, liver, and bone (22% of which involved lesions in the axial skeleton).…”

“…This is longer than expected in a group with metastases. A prolonged interval before systemic therapy change or initiation is required may reduce side effects associated with systemic therapy initiation or change, which may have an impact on quality of life [18,19].…”