Introduction. Lentinan is a polysaccharide isolated from Lentinula edodes, a mushroom traditionally used in Asian medicine for the treatment of various ailments, including oncologic diseases. The aim of this umbrella review is to understand whether lentinan can be a useful integrative remedy for cancer patients.

Methods. PubMed, EMBASE, Web of Science, Cochrane Library, and Google Scholar were systematically searched for relevant meta-analyses from inception to September 29th, 2020. The quality of included studies was assessed with a dedicated NIH (National Institutes of Health) tool.

Results. After database search, 8 meta-analyses met inclusion criteria, all characterized by a fair-to-good methodological quality. Retrieved evidence reported that lentinan can be useful to improve response rate, 1-year survival, performance status, quality of life, and radio/chemotherapy toxicity when administered in adjunct to standard care for some lung and gastrointestinal cancers. In particular, lentinan integrative therapy was able to ameliorate performance status and radio/chemotherapy toxicity in patients with esophageal, gastric, and colorectal cancer, whereas it was capable of improving response rate and adverse effects of standard therapy in subjects with lung malignancies. Individuals with advanced-stage solid tumors also benefited from lentinan integrative supplementation in terms of 1-year survival rate and health-related quality of life.

Discussion. Lentinan may be a valid integrative therapeutic option to administer in adjunct to radio/chemotherapy for selected patients with some solid tumors. Further studies are advised to better understand all potential interactions, side effects, long-term outcomes, disease- and patient-related predictors of efficacy of this complementary therapy.