RecruitingNot ApplicableNCT06978296

HIghly MetAstatic Life Prolonging Therapy-Resistant Prostate Cancer: Role of Stereotactic Radiotherapy for Bone and Lymph Node Metastases (HIMARS)

HIghly MetAstatic Life Prolonging Therapy-Resistant Prostate Cancer: Role of Stereotactic Radiotherapy for Bone and Lymph Node Metastases

Sponsor

Institut Cancerologie de l'Ouest

Enrollment

18 participants

Start Date

Jun 1, 2026

Study Type

INTERVENTIONAL

Conditions

Oligometastatic Prostate Cancer (OMPC)Prostate Cancer Metastatic Disease

Summary

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.

Eligibility

Sex: MALEMin Age: 18 Years

Inclusion Criteria13

Metastatic prostate cancer with clinical progression after the use of androgen-receptor pathway inhibitor, chemotherapy or any other life-prolonging therapy. Patient could have been treated previously by RadioLigand Therapy (RLT).
Performance Status < 3
Bone and/or lymph node metastases based on conventional (CT and bone scan) or metabolic imaging
Bone and/or lymph node metastases suitable for SRT, according to the investigator
Adequate organ function:
Absolute Neutrophil Count (ANC) ≥ 1000/mm3 or
Platelet Count ≥ 50 000/mm3 or
Haemoglobin ≥ 8 g/dL (allowing transfusion or other intervention to achieve this minimum haemoglobin)
Age ≥ 18 years at time of study entry
Written informed consent obtained from the patient prior to performing any protocol-related
Patient is willing and able to comply with the protocol for the duration of the study including undergoing treatment and scheduled visits and examinations including follow up.
Patient has valid health insurance
Life time expected > 3 months

Exclusion Criteria15

Evidence of symptomatic metastases to the lungs, brain, peritoneum or liver
Evidence of diffuse metastatic spread to the bone marrow (e.g. positive super bone scan) or the cerebral spinal fluid as per bone scan (no lumbar puncture required).
Evidence of presence of symptomatic spinal cord compression with indication of neurosurgical decompression.
Patient with symptomatic and/or high-risk tumor volume-to-bone marrow reserve ratio > 50%
Concurrent enrolment in another clinical study, unless it is a non-therapeutic clinical study
Mental impairment (psychiatric illness/social situations) that may compromise the ability of the patient to give informed consent and comply with the requirements of the study;
Patient who has forfeited his/her freedom by administrative or legal award or who is under guardianship;
Patients unable to undergo medical follow-up in the study for geographical, social or psychological reasons.
History of another primary malignancy except for
Malignancy treated with curative intent and with no known active disease ≥2 years before the first dose of SRT and of low potential risk for recurrence
Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease
Adequately treated carcinoma in situ without evidence of disease
Uncontrolled pain that contraindicates patient positioning on the radiotherapy table according to investigator
Patient indicated to or currently treated by cytopenic treatment as chemotherapy or RadioLigand Therapy
Patient under concomitant treatment that may generate severe gastro-intestinal disorder or genito-urinary disorder

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Interventions

RADIATIONStereotactic 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)