Carbon Fiber Transpedicular Screws in Treatment of Spinal Metastatic Disease and Stereotactic Radiotherapy - a Prospective, Randomized Trial

Background: Spinal metastatic disease constitute a serious clinical problem in oncology. Bones are the third most common organ where metastases are located, and the spine is the place where they are most often located. Due to the complexity of the clinical problem, metastatic spine disease remains of interest to many medical specialties: neurosurgery, orthopedics, clinical oncology, radiotherapy and rehabilitation. With the development of modern diagnostic methods and wider access to them, the demand for neurosurgical treatment in this group of patients is growing. Surgical treatment is undertaken in cases of spinal cord compression, instability, spinal deformation or pain that is resistant to radiotherapy. The standard treatment in most cases is posterior instrumentation of the spine using titanium pedicle screws. Unfortunately, these systems cause numerous artifacts in diagnostic imaging, both in CT and MRI. These distortions make it difficult to plan radiotherapy and determine the optimal dose that would avoid healthy tissues. Moreover, artifacts could make difficult postoperative follow-ups aimed at assessing local recurrence. The solution to these problems is the use of radiolucent implants. There are systems based on carbon fibers embedded in PEEK which do not cause typical artifacts for titanium implants.

Study plan: The open, three-arm, prospective randomized study is planned to involve 226 patients with metastatic disease of the spine, with a known or undiagnosed primary site. Patients will be qualified for 2 types of interventions. The first one includes treatment with stereotactic radiotherapy (SBRT) in the first stage of treatment and early instrumentation of the spine with titanium implants. The second type of intervention includes patients qualified for surgical treatment using spine stabilization and postoperative SBRT. Patients within this arm will be randomized into two groups differing in the type of material the instrumentation is made of: carbon-PEEK or titanium. The study group will be patients stabilized with carbon implants, and the control group will be those who will have titanium implants.

Study population: The study includes adult patients with metastatic spine disease, with a known or unknown primary tumor, qualified for SBRT and surgical treatment.

Assumed effects: It is assumed that the treatment proposed in the project would extend progression free survival by several months or achieve local control in an additional 5% of patients. Moreover, by improving the quality of imaging, earlier diagnosis of local recurrences and implementation of appropriate locoregional treatment would be possible.