Medicinal Mushroom Supplements in Cancer: A Systematic Review of Clinical Studies

Purpose of Review: Patients seek clinical guidance on mushroom supplements that can be given alongside conventional treatments, but most research on such fungi has been preclinical. The current systematic review focused on clinical studies of mushrooms in cancer care conducted in the past 10 years. We searched Medline (Ovid), Embase (Ovid), Scopus (Wiley), and Cochrane Library to identify all mushroom studies conducted in humans published from January 2010 through December 2020. Two authors independently assessed papers for inclusion. Recent Findings: Of 136 clinical studies identified by screening 2349, 39 met inclusion criteria. The studies included 12 different mushroom preparations. A survival benefit was reported using Huaier granules (Trametes robiniophila Murr) in 2 hepatocellular carcinoma studies and 1 breast cancer study. A survival benefit was also found in 4 gastric cancer studies using polysaccharide-K (polysaccharide-Kureha; PSK) in the adjuvant setting. Eleven studies reported a positive immunological response. Quality-of-life (QoL) improvement and/or reduced symptom burden was reported in 14 studies using various mushroom supplements. Most studies reported adverse effects of grade 2 or lower, mainly nausea, vomiting, diarrhea, and muscle pain. Limitations included small sample size and not using randomized controlled trial design. Summary: Many of the reviewed studies were small and observational. Most showed favorable effects of mushroom supplements in reducing the toxicity of chemotherapy, improving QoL, favorable cytokine response, and possibly better clinical outcomes. Nevertheless, the evidence is inconclusive to recommend the routine use of mushrooms for cancer patients. More trials are needed to explore mushroom use during and after cancer treatment.