Randomized phase II placebo-controlled study to evaluate the efficacy of topical pure emu oil for joint pain related to adjuvant aromatase inhibitor use in postmenopausal women with early breast cancer: JUST (Joints Under Study).

Aromatase inhibitors are standard of care in women with hormone receptor-positive early breast cancer. Published evidence demonstrates that adverse effects may have an impact on drug compliance, with arthralgias being one of the most commonly reported adverse effects.

Eligible patients were postmenopausal women who had experienced arthralgia following initiation of an aromatase inhibitor. Patients who experienced arthralgias following a minimum of a 3-month treatment on the aromatase inhibitor were randomized to emu oil or placebo oil. The primary endpoint was to assess for a reduction in pain as measured by a visual analogue score after 8 weeks of treatment.

Seventy-three patients comprised the intent-to-treat population, and there was no statistically significant benefit with use of EO. However, there was a statistically significant improvement in pain (visual analogue score was -1.28; p < 0.001) and Brief Pain Inventory severity score -0.88 (p < 0.001), as well as functional interference (Brief Pain Inventory interference -1.10 (p < 0.001) for the entire population following an 8-week administration of EO or placebo oil.

Arthralgias, as a result of aromatase inhibitor use, may be ameliorated by the use of topical oil massaged onto the joint. Further research into interventions for this common side effect is needed.