American Radium Society Guideline for Low-Dose Radiation Therapy

LDRT is considered an appropriate option for selected patients

The guideline concludes that LDRT may be appropriate for patients with symptomatic osteoarthritis who:

• Have persistent pain and functional limitation
• Have not achieved adequate relief with conservative treatments (such as exercise, physical therapy, weight management, NSAIDs, topical medications, braces, or injections)
• Are poor surgical candidates or prefer to delay or avoid surgery
• Understand both the potential benefits and the current limitations of the evidence

Importantly, the guideline does not recommend LDRT as a first-line treatment.

Most patients experience meaningful improvement

After reviewing more than 50 relevant studies, the panel found that LDRT consistently demonstrated:

• Overall response rates of 60%–90%
• Reduction in pain
• Improved joint mobility
• Better quality of life for many patients

The guideline notes that while response rates vary among studies, the overall body of evidence supports a clinically meaningful benefit for many appropriately selected patients.

The evidence is encouraging but still evolving

The panel acknowledges that:

• Much of the published experience comes from Europe.
• Study quality is variable.
• More randomized, sham-controlled, prospective trials are needed.

Despite these limitations, the committee concluded that the available evidence is sufficient to support LDRT as an option in appropriately selected patients rather than considering it purely experimental.

Treatment is delivered at very low doses

The guideline supports the widely used European regimen:

• 0.5 Gy per fraction
• 6 fractions
• Total dose: 3 Gy

Many centers also consider a second course several months later if the initial response is incomplete or pain recurs, consistent with established European practice.

Safety profile

The committee found that LDRT is generally well tolerated. Reported findings include:

• Very few acute side effects
• No meaningful short-term toxicity in modern series
• Theoretical long-term cancer risk is considered very low, especially because the treated population is typically older adults and the doses used are far below those used for cancer treatment.

Patient selection is critical

Patients most likely to benefit generally have:

• Mild to moderate osteoarthritis
• Chronic pain despite standard therapy
• A desire to avoid or postpone surgery

The guideline emphasizes that LDRT should be incorporated into shared decision-making rather than offered routinely to every patient with OA.

Multidisciplinary care is encouraged

One notable feature of the guideline is its emphasis on collaboration among:

• Radiation oncologists
• Rheumatologists
• Orthopedic surgeons
• Primary care physicians

This reflects the view that LDRT should complement, not replace, other evidence-based osteoarthritis treatments.