Advanced Radiation Therapy for Spinal Metastases: Effective Treatment Even for Complex Cases

Table of Contents

• Introduction: Understanding Spinal Metastases Treatment
• Study Design and Patient Selection
• Treatment Approach: Precision Radiation Therapy
• Key Findings: Excellent Control with Minimal Side Effects
• Pain Management Results
• What This Means for Patients
• Study Limitations
• Patient Recommendations
• Source Information

Introduction: Understanding Spinal Metastases Treatment

Up to 70% of bone metastases occur in the spine, causing significant pain, neurological problems, and potential fractures. Conventional radiation therapy provides temporary relief but often requires retreatment due to limited effectiveness. Stereotactic body radiotherapy (SBRT) delivers highly precise, intense radiation doses that can destroy tumors more effectively while sparing healthy tissue.

Recent advances in cancer treatment have improved survival for metastatic patients, particularly those with limited (oligometastatic) disease. These patients may benefit greatly from targeted local treatments like SBRT combined with standard systemic therapies. However, patients with tumors extending into the spinal canal or surrounding tissues have often been excluded from previous studies due to safety concerns.

This international clinical trial specifically investigated whether intensified SBRT could safely and effectively treat spinal metastases, including those with complex anatomical involvement near critical nerves and spinal cord structures.

Study Design and Patient Selection

The study analyzed data from 128 patients with 143 vertebral metastases treated between 2016 and 2023 across 18 medical centers worldwide. Patients had oligometastatic disease (5 or fewer total metastases) with spinal involvement. The median age was 68 years, and 60.2% had breast or prostate cancer as their primary tumor.

Patients were eligible if they were 18 years or older with 1-2 untreated, painful or potentially unstable spinal metastases from confirmed cancer, without progressive neurological symptoms, and with an expected survival of at least one year. Those without pain could participate in a non-randomized arm of the study. All participants provided informed consent, and the trial followed strict ethical guidelines.

Of the 143 treated spinal metastases, 23 (16.1%) had epidural involvement (tumor touching the spinal cord protective covering) and 22 (15.4%) had paraspinal involvement (tumor extending into surrounding tissues). These high-risk cases were specifically included to test the treatment's effectiveness in challenging scenarios.

Treatment Approach: Precision Radiation Therapy

Patients received dose-intensified image-guided SBRT using two different treatment schedules based on their specific anatomy:

• 10 fractions over 2 weeks: 48.5 Gy to the main tumor + 30 Gy to surrounding areas (for tumors with epidural involvement)
• 5 fractions over 1 week: 40 Gy to the main tumor + 20 Gy to surrounding areas (for tumors without epidural involvement)

The treatment used advanced techniques including intensity-modulated radiotherapy and volumetric-modulated arc therapy to precisely target tumors while protecting critical structures like the spinal cord. Treatment planning involved detailed CT and MRI scans to identify exactly where to deliver high doses and where to use lower preventive doses.

This simultaneous integrated boost approach allowed delivering different radiation doses to different areas within the same treatment session, maximizing tumor control while minimizing risks to sensitive neurological structures.

Key Findings: Excellent Control with Minimal Side Effects

The results demonstrated outstanding effectiveness with an excellent safety profile. After a median follow-up of 24 months, only 4 of 142 evaluated metastases (2.8%) showed local recurrence. The cumulative incidence of local failure was just 0.8% at 1 year and 5.3% at 2 years, meaning 94.7% of treated metastases remained controlled at two years.

Survival outcomes were impressive with 94.3% of patients alive at 1 year and 82.2% at 2 years. Statistical analysis revealed that patients with breast or prostate cancer primaries had significantly better survival outcomes compared to other cancer types. The hazard ratio for non-breast/non-prostate cancers was 7.91, meaning these patients had nearly 8 times higher risk of death during the study period.

Remarkably, the presence of epidural or paraspinal involvement did not predict worse outcomes, challenging previous assumptions that these high-risk features would compromise treatment effectiveness.

Safety and Side Effects

The treatment proved exceptionally safe with no grade 4 or 5 adverse events reported. Only 7 patients (5.5%) experienced grade 3 side effects, which were managed effectively. Most importantly, no patients developed radiation-induced myelopathy (spinal cord damage) or plexopathy (nerve bundle damage), which are the most concerning potential complications of spinal radiation.

The most common side effects were fatigue (32.8% of patients) and pain (28.1%), which were generally mild to moderate in severity. These findings demonstrate that even with dose-intensified treatment, the therapy remained well-tolerated.

Vertebral Compression Fractures

Vertebral compression fractures (VCFs) are a known risk after spinal radiation. The study identified 12 VCFs total: 4 pre-existing fractures (2.8%) and 8 new fractures developing after treatment (5.6%). The estimated risk of new fractures was 6.7% at 1 year and 9.8% at 2 years, which compares favorably to other SBRT techniques.

No specific factors predicted fracture risk, including tumor type, spinal stability scores, or tumor size. This suggests that fracture risk remains manageable with this treatment approach.

Pain Management Results

For the 54 metastases that were painful before treatment, significant pain improvement occurred at all measured time points. Pain scores on the visual analog scale (0-10 scale) decreased by an average of 2.8 points at 6 months, 3.2 points at 12 months, and 2.6 points at 24 months, all statistically significant improvements.

The proportion of patients achieving clinically meaningful pain reduction (≥2 points on pain scale) increased over time: 38.9% at 1 month, 48.1% at 3 months, 53.7% at 6 months, and 55.6% at 12 months. This demonstrates durable pain control that benefits the majority of treated patients.

What This Means for Patients

This study provides strong evidence that dose-intensified SBRT offers excellent long-term control of spinal metastases with minimal serious side effects. The treatment works effectively even for complex cases with tumors extending into the spinal canal or surrounding tissues, which were previously considered high-risk for treatment failure.

Patients with breast or prostate cancer metastases derived particular benefit, showing significantly better survival outcomes. The treatment provided durable pain relief for most patients while maintaining spinal stability with acceptable fracture rates.

The multifraction approach (treatment over 5-10 sessions) appears to balance maximum effectiveness with minimal complications, particularly regarding spinal cord protection and fracture risk reduction.

Study Limitations

While the results are impressive, several limitations should be considered. The study ended earlier than planned due to slow patient recruitment, which limited the total number of participants. The relatively small number of local failures (only 4 cases) made detailed analysis of risk factors challenging.

The non-randomized design for some patients means selection bias may have influenced results. Additionally, the follow-up period of 2 years, while substantial, may not capture very long-term outcomes or late complications that could emerge beyond this timeframe.

Finally, the study population was predominantly European, and results might vary in more diverse populations or different healthcare settings.

Patient Recommendations

Based on these findings, patients with limited spinal metastases should consider several important points:

1. Seek specialized evaluation: This advanced radiation technique requires expertise available at major cancer centers
2. Discuss all options: Consider SBRT particularly if you have 1-5 total metastases, especially from breast or prostate primary cancers
3. Don't exclude complex cases: Even tumors near the spinal cord may be treatable with this approach
4. Prepare for treatment course: The 5-10 session treatment requires precise daily targeting but typically causes only mild side effects
5. Monitor for fractures: While risk is manageable, discuss bone health with your oncology team

Patients should have detailed discussions with their radiation oncologists about whether this approach is appropriate for their specific situation, considering factors like cancer type, metastasis location, and overall health status.

Source Information

Original Article Title: Dose-intensified SBRT for vertebral oligometastases: results from a prospective clinical trial

Authors: Matthias Guckenberger, Lotte Wilke, Charlotte Billiet, Susanne Rogers, Ciro Franzese, Daniel Schnell, Mateusz Spałek, Daniel M. Aebersold, Hossein Hemmatazad, Thomas Zilli, Judit Boda-Heggemann, Brigitta G. Baumert, Jean-Jacques Stelmes, Franziska Nägler, Philipp Gut, Christian Weiß, Alessio Bruni, Frank Zimmermann, Robert Förster, Jörg Zimmer, Indira Madani

Publication: Radiotherapy and Oncology 208 (2025) 110940

Note: This patient-friendly article is based on peer-reviewed research from an international clinical trial conducted at 18 medical centers between 2016-2023.