An interventional study of Stereotactic body radiotherapy (SBRT) in Prostate Cancer Metastatic Disease and Oligometastatic Prostate Cancer (OMPC), sponsored by Institut Cancerologie de l'Ouest. Recruiting at 1 site in France. Open to male participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-04.
Sponsored by Institut Cancerologie de l'Ouest · Not applicable, Interventional, and Treatment
The investigators propose redefining this concept by focusing on volume rather than the number of metastases. To achieve this, the investigators aim to determine the Maximum Tolerated Volume (MTV) of metastatic lesions treatable with SRT (Stereotaxic radiotherapy) in a phase 1 study. In this study, the investigators will recruit patients with high-volume metastatic disease in bones or lymph nodes and progressively irradiate a volume-escalated subset of the total lesions. The selection will prioritize lesions at higher risk of causing pain or complications, such as fractures, spinal compression, or vascular compression. The investigators hypothesis is that SRT targeting multiple metastases (with a total volume ≤ MTV) will extend the duration without refractory pain and/or tumor-related complications in patients with castration-resistant and chemo-refractory prostate cancer.
7,046 studies on the registry are indexed under Prostatic Neoplasms; 1,580 are open to participants now.
This study's planned enrollment of 18 is below the median of 60 across 5,348 interventional studies indexed under Prostatic Neoplasms.
Browse Prostatic Neoplasms studies →Institut Cancerologie de l'Ouest is the lead sponsor of 109 studies on the registry; 20 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Adequate organ function:
Exclusion Criteria:
History of another primary except for
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Absolute neutrophil count (ANC)
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
This volume escalation will be performed until MTV is reached. Level cohort is defined by: volume level Irradiation volume / Bone Marrow Reserve as below: level -1: 20% level 1 (start level): 30% level 2: 40% level 3: 50%
Radiation: Stereotactic body radiotherapy (SBRT)
The acceptable regimens are: * 27 Gy / 3 fractions / 3 fractions per week * 35 Gy / 5 fractions / 3 fractions per week An interval of at least 24 hours should be kept between two consecutive fractions. Prescription must be defined on 80% isodose or higher, maximum dose up to 130% of the isodose prescription. At least 90% of the Planning Target Volume should receive the prescribed dose. A coverage of \<90% of the Planning Target Volume will be considered as acceptable deviation, and coverage of \<80% of the target volume as an Unacceptable Deviation. At least 90% of the Gross Tumoral Volume should receive the prescribed dose. Only a part of the Gross Tumoral Volume\_Total could be considered for radiation, depending on the ratio with Bone Marrow Reserve. High-risk and/or symptomatic metastases will be prioritized over other metastases. Anatomic bone marrow reserve (BMR) will be first determined for each patient: BMR = Total trabecular bone - (Total trabecular bone ∩ GTV\_Total)
Maximum tolerated volume (MTV)
The MTV will be defined as the highest volume that can be treated with an acute toxicity of grade \< 3 (CTCAE V5.0 scale) in one third of patient and will allow us to determine the recommended phase II volume under the assumption that higher volumes are likely to be more toxic. The maximum tolerated Volume (MTV) is defined as the volume at which 2 Dose-Limiting Toxicity (DLT) were observed among 3 to 6 patients. DLT are considered as: * Death clearly related to irradiation * Intractable pain despite oral or intravenous opioids and/or corticosteroids (EVA \> 4 and increase of 2 from EVA baseline) * Any new grade ≥ 3 toxicity (CTCAE V5.0 scale) compared to baseline among: * Anemia * Febrile Neutropenia * Hemorrhage within grade ≥3 thrombocytopenia * Any gastro-intestinal-related disorder * Any genito-urinary-related disorder * Pneumonitis Bone marrow reserve will be determined by CT-base automatic tool.
Time frame: 12 weeks
Number of toxicity related to radiotherapy as assessed by CTCAE v5.0
Acute (≤ 12 weeks) and late (\>12 weeks) toxicity will be evaluated according to NCI-CTCAE v5 grading
Time frame: through study completion
Recommended volume for irradiation by SRT for phase-II
The Recommended Volume (RV) corresponds to the volume of the level immediately below the MTV. This Recommended Volume for irradiation by SRT will then be applied for phase 2.
Time frame: 12 weeks
Pain relief assessed by EVA scale
Global pain evaluation (EVA) will be measured at baseline, 1-, 3- and 6-month following SRT. Score is 0 (no pain) to 10 (maximal pain)
Time frame: 6 months
Time to first pejorative event among tumour-related complication (bone, neurological or vascular compression) and/or death
Time to first worsening event due to tumor progression (as seen on thoraco-abdomino-pelvic CT scan): including bone displacement, spinal cord or neurological compression, and vasculo-lymphatic compression will be assessed.
Time frame: 2 years
Number of deceased patients
Overall survival is defined as the time interval between the date of registration and the date of death irrespective of the cause
Time frame: 2 years
To assess the functioning bone marrow reserve at baseline and after SRT
Functioning bone marrow reserve is quantified on 99Tc-sulfur colloid SPECT-CT by automatic delineation at baseline and at 3 months after SRT (GTV\_Total/functioning BMR)
Time frame: Baseline and 3 months after start of SRT
To compare the anatomical and functioning assessment of the bone marrow reserve
Comparison of the tumor volume-to-bone marrow reserve ratio: GTV\_total/functioning BMR and GTV\_Total/anatomic BMR
Time frame: Baseline and 3 months after start of SRT
Plan to share: Undecided
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