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

Inclusion Criteria

• •Age ≥ 18 years
• •History of breast cancer, estrogen receptor positive (ER+), Her 2 positive or negative
• •Fatigue ≥ 4/10
• •Currently post-menopausal (as defined by National Comprehensive Cancer Network (version 4.2024), taking any aromatase inhibitor in the curative setting and planning to be on such for at least 8 weeks after registration. \[Patients on concurrent ovarian suppression (such as with leuprolide acetate, goserelin) are allowed\]; CDK 4/6 inhibitors abemaciclib, ribociclib ARE allowed
• •Prior treatment: last chemotherapy ≥ 90 days prior to randomization (if treated with chemotherapy)
• •On a stable dose of pain medications if pain medications are being regularly used. (i.e., no change in dosage in the past 30 days)
• •If on supplements, must be on stable dose with no plan to change; not on or planning any acupuncture or other specific supportive modalities for fatigue or AI arthralgias
• •Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1 or 2
• •White blood cell count (WBC) ≥ 3,000/mm\^3 (obtained ≤ 30 days prior to randomization)
• •Hemoglobin ≥ 10 g/dL (obtained ≤ 30 days prior to randomization)
• •Platelet count ≥ 100,000/mm\^3 (obtained ≤ 30 days prior to randomization)
• •Total bilirubin ≤ 1.5 x upper limit of normal (ULN) (obtained ≤ 30 days prior to randomization)
• •Alanine aminotransferase (ALT) or aspartate transaminase (AST) ≤ 1.2 x ULN (obtained ≤ 30 days prior to randomization)
• •Prothrombin time (PT)/activated partial thromboplastin time (aPTT) ≤ 1.5 x ULN (obtained ≤ 30 days prior to randomization)
• •Negative pregnancy test done ≤ 7 days prior to registration, for persons on concurrent ovarian suppression only
• •Provide informed consent
• •Ability to complete questionnaires
• •Willing to return to enrolling institution during the active monitoring phase of the study
• •Patients who have had a recent surgery or procedure should be healed and cleared by their clinician and/or surgeon per local standards, prior to registration