OLIGO-10: Stereotactic Ablative Radiation Therapy for Metastatic Patients With 6 to 10 Metastatic Sites

Currently, the standard of care for patients with diagnosed metastatic cancer is drug therapy (chemotherapy, targeted therapy, or immunotherapy). However, the approach to oligometastatic disease (1-5 metastases) is evolving. An increasing number of de novo, persistent, and progressive oligometastatic tumors are now being treated with curative intent, with radiation therapy among the most effective treatment options, applied to metastatic sites in ablative doses. Emerging results from the SABR-COMET 3 and 5 trials, which investigate stereotactic ablative radiotherapy for patients with 1-3 and 1-5 metastatic sites, demonstrate a clear improvement in overall survival. However, patients with more than five metastases remain in a gray area.

The aim of our study is to assess the safety and effectiveness of radiation treatment for patients with tumors of various localizations and 6 to 10 metastases in the bones and internal organs. Stereotactic radiation therapy will be applied to patients with persistent or progressive metastatic forms of tumors, without changing their ongoing drug therapy regimen.

1. A patient with a previously verified diagnosis of a malignant neoplasm of any localization (ICD 10-11 codes C) who meets the inclusion criteria, after approval by the tumor board for the study group, will undergo the following procedures:

   Three-dimensional/four-dimensional computed tomography for simulation using specialized fixation devices (the choice of the CT method and fixation devices will depend on the location of the metastasis).

   The resulting images will be added to the contouring program.

   Delineation of targets and organs at risk will be performed.

   Clinical volumes and error margins will be determined.
2. The total dose per target and dose limits for critical structures will be prescribed.

   Dosimetric planning for the course of external beam radiation therapy will be carried out.

   Irradiation sessions will be conducted on a linear accelerator with a multi-leaf collimator, including a function for visual control of the target using cone beam tomography with kilo-voltage/mega-voltage radiation.

   When the target is localized in the lungs, liver, or adrenal glands, to reduce the radiation load on surrounding healthy tissues and achieve necessary control over the position of the metastasis, irradiation will be performed with a deep breath hold or at specific phases of respiration.
3. Tumor Localization / Description / Total Focal Dose (Gy) / Number of Fractions / Single Focal Dose (Gy) / Irradiation Mode:

   Lung Tumors:

   Tumors ≤ 3 cm located in the parenchyma: TD 45 Gy in 3 fractions with 15 Gy each day Tumors adjacent to the chest wall or \< 3 cm: TD 50 Gy in 5 fractions with 10 Gy each day Tumors within 2 cm of the mediastinum or brachial plexus: TD 60 Gy in 8 fractions with 7.5 Gy each day Bones: TD 24 Gy in 3 fractions with 8 Gy each day

   Brain Metastases:

   Tumor volume from 0.5 to 5 cm³: TD 20-22 Gy in 1 fraction at a time Tumor volume from 5 to 10 cm³: TD 16-18 Gy or TD 18-20 Gy in 1 fraction at a time Liver: Radiation regimen selection based on the tolerance of surrounding tissues and proximity to critical structures: TD 30-60 Gy in 3-8 fractions with 6-15 Gy each day

   Adrenal Glands: TD 60 Gy in 8 fractions with 7.5 Gy each day
4. Expected Duration of Patient Participation in Clinical Testing:

Pre-hospital period: Comprehensive examination of the patient before treatment. Inpatient period: Includes pre-radiation preparation for up to 3 working days, SABR treatment for 1 to 8 working days.

Follow-up period: 3, 6, 9, and 12 months post-treatment; thereafter, follow-up will occur every 6 months up to 60 months.

Collection and processing of received data.

Eligibility Criteria:
Inclusion Criteria:

* ECOG status 0-3
* Persistent or progressive cancer disease with 6 to 10 metastases
* ≤ 5 metastases in one organ
* Life expectancy \> 6 months for intracranial lesions
* Inability to surgically resect all metastatic lesions
* Positive tumor board decision for trial inclusion
* Signed informed consent

Exclusion Criteria:

* ECOG status 4
* De novo metastatic disease
* Radiological complete response after drug therapy
* Brain metastasis only
* Brain metastasis \> 3 cm, requiring neurosurgery
* Size of any metastasis \> 5 cm
* Previous radiation therapy for any metastatic site
* Leptomeningeal, pleural, or peritoneal carcinomatosis
* Spinal cord compression, requiring neurosurgery
* Invasion of great vessels, skin, or GI tract
* Negative tumor board decision for trial inclusion
* Unsigned informed consent