NCT06978296

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

• Status: Not Yet Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 18 (estimated)
• Sponsor: Institut Cancerologie de l'Ouest · Academic / Other
• Sex: Male
• Age: 18 Years
• Healthy volunteers: Not accepted

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.

Conditions

• Prostate Cancer Metastatic Disease
• Oligometastatic Prostate Cancer (OMPC)

Interventions

Type	Name	Description
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)

Timeline

• Start date: 2026-01-15
• Primary completion: 2027-10-01
• Completion: 2029-07-01
• First posted: 2025-05-18
• Last updated: 2025-12-08

Locations

1 site across 1 country: France