Fungal beta-glucans as adjuvants for treating cancer patients - A systematic review of clinical trials

Abstract

Background & aims: Fungal β-glucans have been considered as biological response modifiers (BRMs) promoting stimulation of immune system according to numerous scientific publications performed in vitro and in vivo. Some clinical trials involving such compounds started to be published since 1980's. This systematic review aimed to compile and compare clinical studies using these β-glucans as adjuvants on patients undergoing cancer treatment. Healthy subjects and β-glucans from other sources were excluded.

Methods: It was developed according to PRISMA-P guidelines (PROSPERO registered n. CRD42020151539), using PICO criteria and the following databases: PubMed, Scielo and LILACS.

Results: We found 1018 articles and after removing duplicated records, select by title/abstract and full-text, only 9 studies remained and 7 more were manually added, totalizing 16 trials involving 1650 patients, with arm sizes varying from 9 until 200 patients. The selected studies (published since 1992-2018) included subjects with diagnosis of 9 types of cancer. The studies used different sources of β-glucans, such as yeast (Saccharomyces cerevisiae), mushrooms (Lentinula edodes and Schizophyllum commune) and non-described fungal sources.

Conclusions: It was observed that the administration of β-glucan is safe and well-tolerated. Most of the trials pointed that concomitant administration of β-glucan with chemo or radiotherapy reduced the immune depression caused by such treatments and/or accelerated the recovery of white blood cells counts. However, some articles also commented that no statistical difference was encountered between β-glucan treated vs. control groups, which gives a controversial conclusion about the β-glucan effects. The great diversity among the methodology studies and insufficient information was an impeditive for achieving profound statistical analysis, therefore a narrative report of the included studies was performed indicating that further evidences are required to determine the efficacy of this adjuvant in the cancer treatment.

Keywords: Cancer treatment; Clinical trials; Fungal β-glucans; Systematic review.