Low-dose radiation therapy for peripheral joint osteoarthritis: Early U.S. community experience with pain, function, and medication outcomes

Background / Significance: Osteoarthritis (OA) causes chronic pain and functional decline in older adults, yet treatment options are limited for patients who cannot tolerate long-term NSAIDs or opioids. Low-dose radiation therapy (LDRT) has shown efficacy in European studies, but U.S. data are sparse. This student-led study reports early outcomes from a community oncology practice implementing LDRT for OA, focusing on pain, function, and analgesic trends. Methods: Thirty patients (55 joints) with OA were treated with LDRT (3 Gy in 5-6 fractions, 0.5 Gy/fraction). Pain was assessed using the Numeric Rating Scale (NRS, 0-10) and patient-assessed global improvement using the von Pannewitz Score (VPS, 0-4) at baseline, end of treatment (EOT), and ~1-month follow-up. Analgesic use was recorded at both time points. Paired t-tests and one-way ANOVA by joint site were used to assess changes. Results: Mean baseline NRS = 8.0 (±1.2); follow-up = 3.3 (±2.1), a mean reduction of 4.7 points (p < 0.001). Eighty-three percent (25/30) achieved ≥2-point improvement; 70% (21/30) ≥3 points; 40% (12/30) ≥5 points. VPS at follow-up indicated moderate improvement in 39%, excellent in 25%, and complete response in 9%. Analgesic use decreased in 23% (7/30), and no patients required escalation or new medications. No ≥ Grade 2 toxicities occurred. Conclusions: LDRT was safe, feasible, and provided substantial pain relief and improved function with parallel reductions in analgesic use. The absence of medication escalation underscores its potential as a non-pharmacologic, opioid-sparing therapy for OA pain. These real-world U.S. data support further prospective evaluation of LDRT in geriatric pain management. Disclosure: No external funding or conflicts of interest. Study conducted under student investigator leadership with faculty supervision.