Single-fraction prostate-specific membrane antigen positron emission tomography- and multiparametric magnetic resonance imaging-guided stereotactic body radiotherapy for prostate cancer local recurrences.

To analyse the efficacy and safety of focal prostate-specific membrane antigen positron emission tomography (PSMA-PET)- and multiparametric magnetic resonance imaging (mpMRI)-guided single-fraction stereotactic body radiotherapy (SBRT) for the treatment of prostate cancer (PCa) local recurrences. Patients with PSMA-PET-positive PCa local recurrences treated with single-fraction SBRT between 2016 and 2020 were included. Identification for subsequent recurrences or metastatic spread based on increasing prostate-specific antigen (PSA) levels were evaluated using PSMA-PET imaging. A total of 64 patients were identified. Patients received various treatments before SBRT (31 patients with radical prostatectomy [RP], 18 external beam radiotherapy [EBRT] with RP, five EBRT, and the remaining 10 other combinations). The median follow-up was 21.6 months. The median PSA level before SBRT was 1.47 ng/mL. All patients received a single-fraction treatment with a median prescription dose and isodose line of 21 Gy and 65%, respectively. At the time of SBRT, six patients (9%) received an androgen deprivation therapy (ADT). PSA levels decreased after SBRT (P = 0.03) and three local recurrences were detected during the follow-up. The progression-free survival after 1-, 2-, and 3-years was 85.3%, 65.9%, and 51.2%, respectively. Six patients (9%) started ADT after SBRT due to disease progression. The rates of newly started ADT after 1-, 2-, and 3-years were 1.8%, 7.3%, and 22.7%, respectively. Grade 1 or 2 toxicities occurred in six patients (9%); no high-grade toxicity was observed. While the available data for SBRT in the PCa local recurrence setting describe outcomes for fractionated irradiations, the findings of this first analysis of single-fraction, PSMA-PET- and mpMRI-guided focal SBRT are encouraging. Such treatment appears to be a safe, efficient, and time-saving therapy even in intensively pretreated patients. Recurrence-directed treatments can delay the use of ADT and could avoid prostate bed irradiation in selected patients.

Ehret F ，Hofmann T ，Fürweger C ，Kufeld M ，Staehler M ，Muacevic A ，Haidenberger A ... -  《-》

Stereotactic Body Radiotherapy for Oligometastatic Prostate Cancer Detected via Prostate-specific Membrane Antigen Positron Emission Tomography.

The management of oligometastatic prostate cancer (PCa) remains controversial, especially following the introduction of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging. To assess whether stereotactic body radiotherapy (SBRT) provides a potential for cure in a selected group of patients with oligometastatic PCa in the PSMA-PET era. This was a prospective, single-centre study of patients with oligometastatic PCa undergoing SBRT from November 2014 to July 2016. We included patients with relapsed PCa receiving SBRT with PSMA-PET-confirmed oligometastases (n=1-3) confined to lymph nodes (LNs) or bone without androgen deprivation therapy. SBRT schedules included 20Gy/1# or 24Gy/2# to bone metastases, and 50Gy/5# or 30Gy/3# to LNs. The primary endpoint was biochemical failure (BF) defined as a prostate-specific antigen (PSA) level of nadir + 0.2 ng/ml following SBRT. Fifty-seven patients were eligible, of whom 50 (88%) had undergone radical prostatectomy. The median time from definitive treatment to SBRT was 5.6 yr. A total of 73 lesions were treated: 44 patients had one metastasis, while 13 had two or three. Thirty-seven patients (65%) had LN-only disease, while 18 (31%) had bone-only metastasis. Median follow up was 16 mo. The median biochemical disease-free survival (bDFS) for the cohort was 11 mo, with 31.9% bDFS at 15 mo. All patients with BF (n=43) underwent a repeat PSMA-PET scan, which revealed no in-field failures. Median bDFS was not affected by prostate-specific antigen (PSA) at diagnosis, Gleason score, time from diagnosis to SBRT, site (bone vs LN), PSA doubling time before SBRT, or number of metastases. Failures were somewhat less common in patients with low PSA before SBRT. Toxicity was rare: no patients developed grade ≥2 late toxicity. SBRT delivered very high rates of local control with minimal toxicity. However, distant recurrences occurred in most patients by 15 mo and did not appear to be predicted by known prognostic factors. In this report, we looked at outcomes after the use of stereotactic body radiotherapy for patients with prostate cancer spread to one to three lymph nodes or bones as detected by positron emission tomography scans. We demonstrated high rates of control of the treated lesions with low toxicity, but by 15 mo more than two-thirds of patients had developed recurrent cancer outside the treated area.

Kneebone A ，Hruby G ，Ainsworth H ，Byrne K ，Brown C ，Guo L ，Guminski A ，Eade T ... -  《European Urology Oncology》

Stereotactic Radiotherapy for Lesions Detected via (68)Ga-Prostate-specific Membrane Antigen and (18)F-Fluorodexyglucose Positron Emission Tomography/Computed Tomography in Patients with Nonmetastatic Prostate Cancer with Early Prostate-specific Antigen P

Dual-tracer positron emission tomography/computed tomography (PET/CT) with a 68Ga-labelled prostate-specific membrane antigen (PSMA) ligand and 18F-fluorodeoxyglucose (FDG) improves detection of metastatic heterogeneity and burden in patients with nonmetastatic prostate cancer (nmPCa). However, there is limited prospective evidence regarding its impact on the efficacy of stereotactic body radiotherapy (SBRT). To evaluate metastasis-free survival (MFS) and toxicity after SBRT to dual-tracer PET/CT-detected metastases in patients with nmPCa and early prostate-specific antigen (PSA) progression on androgen deprivation therapy (ADT; PSA ≤2 ng/ml). Patients were prospectively screened using dual-tracer PET/CT between April 2019 and October 2020. SBRT was recommended for patients with five or fewer nonvisceral metastases (SBRT group). Patients without detectable metastases (N-/M- group) and those who refused SBRT (ADT group) continued to receive ADT. Patients were followed with conventional imaging. SBRT to each PET/CT-detected metastasis. Kaplan-Meier methods were used to determine MFS. Toxicity was evaluated using Common Terminology Criteria for Adverse Event v4.0. Seventy-four consecutive patients were screened. The median PSA and PSA doubling time were 0.59 ng/ml and 4.56 mo, respectively. Overall, 54 patients had metastases and 17 had PSMA-/FDG+ disease. Seven patients were excluded from the MFS analysis, including two with a history of abiraterone treatment and five with more than five metastases. The median follow-up was 21.4 mo. The ADT group had shorter MFS than the SBRT group (11.0 mo vs not reached; hazard ratio [HR] 4.69, 95% confidence interval [CI] 2.92-25.0; p < 0.001) and the N-/M- group (11.0 mo vs not reached; HR 8.78, 95% CI 4.04-40.30; p < 0.001). There was no significant difference in median MFS between the SBRT group and the N-/M- group (p = 0.261). A PSA response >90% was achieved by 86% of patients in the SBRT group. There were no grade ≥3 adverse events after SBRT. The nonrandomized design is the major study limitation. Dual-tracer PET/CT-guided SBRT delivered superior local control rates in comparison to ADT alone and had minimal toxicity. We investigated metastasis-targeted radiotherapy for patients with up to five prostate cancer metastases detected with two different radioisotope scans. Our results show that this approach yields promising metastasis-free survival and low toxicity.

Pan J ，Wei Y ，Zhang T ，Liu C ，Hu X ，Zhao J ，Gan H ，Liu W ，Zhu B ，Wu J ，Wang B ，Song S ，Ye D ，Zhu Y ... -  《European Urology Oncology》

Reirradiation for isolated local recurrence of prostate cancer: Mono-institutional series of 64 patients treated with salvage stereotactic body radiotherapy (SBRT).

Jereczek-Fossa BA ，Rojas DP ，Zerini D ，Fodor C ，Viola A ，Fanetti G ，Volpe S ，Luraschi R ，Bazani A ，Rondi E ，Cattani F ，Vavassori A ，Garibaldi C ，Alessi S ，Pricolo P ，Petralia G ，Cozzi G ，De Cobelli O ，Musi G ，Orecchia R ，Marvaso G ，Ciardo D ... -  《-》

Long-term outcomes of SBRT for PSMA PET detected oligometastatic prostate cancer.

Oligometastatic disease in prostate cancer (PCa) is a challenging clinical scenario encountered more frequently with the widespread adoption of PSMA-PET. SBRT aims to defer androgen deprivation and may deliver sustained biochemical failure (BF) free survival in selected patients. Little long-term data is currently available regarding the effectiveness of this approach. A retrospective single institution study of PSMA-PET directed SBRT without initial ADT for oligo-metachronous PCa. Median dose/fractionation was 24 Gy in 2# to bones and 30 Gy in 3# to lymph nodes. The primary endpoint was time to BF (PSA + 0.2 ug/L above nadir). Secondary endpoints included time to ADT for relapse (i.e. palliative ADT), BF defined as PSA nadir + 2 ug/L, toxicity, patterns of failure and survival. Patients were excluded if they received ADT with their SBRT, had short disease-free interval, or > 3 metastases on PSMA-PET. 103 patients treated from November-2014 to December-2019 were analysed from our prospective database. Median follow-up was 5 years. 64 patients were treated for nodal only disease, 35 bone only and 4 mixed. 15% were free of any BF at 5 years with median time to BF of 1.1 years. 32% (33/103) of patients had further curative-intent radiation treatment following their first BF after SBRT, including subsequent SBRT. Eight patients underwent potentially curative treatment for their second or third relapse. Allowing for salvage treatment, 29/103 (28%) were biochemically disease free at last follow up. At 5 years, 39% of patients had never received any ADT and 55% had not started ADT for relapse with a median time to ADT for relapse of 5.5 years. There were 2 grade 3 toxicities (rib fracture and lymphoedema), and no local failures. PSMA-PET guided SBRT for oligo-metachronous PCa recurrence in appropriately triaged patients results in excellent local control, low toxicity and over 50% ADT free at 5 years.

Mohan R ，Kneebone A ，Eade T ，Hsiao E ，Emmett L ，Brown C ，Hunter J ，Hruby G ... -  《-》