Reishi Mushroom Extract for Fatigue and/or Arthralgias/Myalgias in Patients With Breast Cancer on Aromatase Inhibitors

This phase II trial tests how well Reishi mushroom extract works in treating fatigue and/or joint/muscle pain (arthralgias/myalgias) in patients with breast cancer on aromatase inhibitors. Fatigue and arthralgias/myalgias are common symptoms in breast cancer patients taking aromatase inhibitors (AI). Given the long duration of AI treatment for some women (up to 10 years), these symptoms can significantly impact quality of life and premature discontinuation of AIs, a beneficial medication. Reishi mushrooms are among several medicinal mushrooms that have been used for hundreds of years, mainly in Asian countries, to help enhance the immune system, reduce stress, improve sleep, and lessen fatigue. Reishi mushroom extracts have not been studied explicitly for treatment-induced arthralgias/myalgias, but have been shown to improve quality of life, muscular strength, pain, and flexibility. Information from this study may help researchers determine the effect of Reishi mushroom extract on fatigue and arthralgias/myalgias in breast cancer patients receiving an AI.