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

The guideline does not recommend LDRT as a first-line treatment.

Most studies report meaningful improvement

After reviewing 52 studies, the panel found that studies generally reported:

• 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 promising but not settled

The panel acknowledges that:

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

Even so, the committee concluded that the evidence is strong enough to support LDRT as an option for carefully selected patients, rather than treating it as 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

If the first course brings limited or no response, the panel recommends considering a second course at 8 to 12 weeks, consistent with established European practice.

Few side effects

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.

Choosing the right patients matters

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 says LDRT should be a shared decision between patient and doctor, not something offered to every patient with osteoarthritis.

Specialists should work together

The guideline calls for collaboration among:

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

LDRT is meant to add to other evidence-based osteoarthritis treatments, not replace them.