Stereotactic Re-irradiation of Local Recurrences of Prostate Cancer After Radiotherapy — PROSTARE  

Radiotherapy Clinical Trial

Official title: Phase II Study - Stereotactic Re-irradiation of Local Recurrences of Prostate Cancer After Radiotherapy - PROSTARE (PROstate Cancer STereotActic REirradiation) Trial

Status Recruiting

Clinical Trial Summary

The goal of this clinical study is to evaluate the toxicity and efficacy of re-irradiation using focal stereotactic body radiotherapy (SBRT) in patients with local recurrence of prostate cancer after definitive or post-operative radiotherapy.

The main question is the tolerance of such treatment, concerning the incidence of Grade ≥ 2 and Grade ≥ 3 GU and GI toxicity. Also the efficacy of SBRT will be measured in terms of Biochemical Control.

Secondary endpoints include: Biochemical Response, Metastases-Free Survival, Relapse-Free Survial, Overall Survival and patients' reported tolerance measured with Quality of Life questionnaires (QoL C-30 and PR-25).

The evaluation of the tolerance and effectiveness of stereotactic radiotherapy (SBRT) will be performed in 3 subgroups: in patients with local recurrence after conventionally fractionated definitive radiotherapy (Group A) or ultrahypofractionated definitive SBRT (Group C) or after prostatectomy and post-operative radiotherapy (Group B).

The study group is planned to include 60 patients.

Clinical Trial Description

The diagnosis of local recurrence after radiotherapy in patients with prostate cancer is a serious clinical problem. Interventional salvage treatment in the previously irradiated area is difficult with safety issues of special concern. According to the MASTER meta-analysis the effectiveness of various local salvage methods turned out to be comparable in patients with local recurrence after definitive radiotherapy. Stereotactic radiotherapy (SBRT) had the best toxicity profile, so this non-invasive treatment may be a suitable alternative to other methods. A particular problem is local recurrences after post-prostatectomy radiotherapy. The data on SBRT in such setting are even more scarce than in the case of relapses after definitive radiotherapy. Still, they show a low percentage of serious adverse events of grade ≥3 and good treatment tolerance.

Considering the own experience with re-irradiation of patients with prostate cancer, it was decided that re-irradiation should be carried out in the form of focal SBRT. With the objective of enhancing the safety and quality of salvage re-irradiation, and a comprehensive evaluation of the efficacy of this treatment it was determined that it should be implemented as a prospective phase II study- PROSTARE (PROstate cancer STereotActic Reirradiation).

The evaluation of the tolerance and effectiveness of stereotactic radiotherapy (SBRT) will be performed in patients with local recurrence after conventionally fractionated definitive radiotherapy (Group A), ultrahypofractionated definitive SBRT (Group C), or after prostatectomy and postoperative radiotherapy (Group B).

The study will be conducted as a single-centre study. The evaluation of the safety and effectiveness of such treatment could help develop qualification criteria for repeated irradiation. As a consequence, this should allow for the implementation of this form of treatment into radiotherapy protocols and then, in a controlled and safe way, into clinical practice.

The total sample size will comprise 60 patients. The expected recruitment period is 6 years (10 patients per year).

Requirements for reirradiation with SBRT:

1. Both PET-PSMA and MR of the prostate or prostate bed are required in patients with recurrence after definitive radiotherapy or surgery followed by radiotherapy

2. Fiducial implantation is not routinely required

3. Empty rectum and empty/partially empty bladder (improved reproducibility)* during treatment planning and during each fraction of stereotactic radiotherapy

4. Treatment with a linear accelerator is preferred

5. CBCT must be performed before each fraction of SBRT with verification for tumour location (GTV)**

6. Focal radiotherapy, i.e., irradiation of only the visible tumour with an appropriate margin

7. Hormonal treatment is not routinely recommended (according to the ESTRO ACROP consensus)

• up to the decision of the attending physician

• Principles of preparation with laxatives - Bisacodyl is advocated 4-5 hours before SBRT. If the diameter of the rectum on the CT for treatment planning exceeds 4 cm in diameter, the procedure should be repeated after appropriate preparation of the patient.

• If stereotactic radiotherapy is conducted on the CyberKnife - KV imaging and Tracking verification are required; additionally an assessment of bladder filling in ultrasonography should be performed ;

Related Conditions & MeSH terms

• Local Recurrence of Malignant Tumor of Prostate
• Prostatic Neoplasms
• Radiotherapy
• Recurrence

• NCT number: NCT06201078
• Study type: Interventional
• Source: Maria Sklodowska-Curie National Research Institute of Oncology
• Contact: Wojciech Majewski, MD, PhD
• Phone: +48322788001
• Email: wojciech.majewski@gliwice.nio.gov.pl
• Status: Recruiting
• Phase: Phase 2
• Start date: July 31, 2023
• Completion date: December 31, 2029