The Effect of Fungal Nutraceutical Supplementation on Postoperative Complications, Inflammatory Factors and Fecal Microbiota in Patients Undergoing Colorectal Cancer Surgery with Curative Intent: A Randomized, Placebo-Controlled, Double-Blind Clinical Trial

Background/Objectives: The combination of different fungal extracts could be beneficial to cancer patients due to their role in gut microbiota modulation and anti-inflammatory activity. The study aimed to evaluate whether fungal extract supplementation reduces postsurgical complications in patients with colorectal cancer undergoing curative surgery. Methods: Patients were randomized to receive the nutraceutical Micodigest 2.0 or a placebo until surgery. Surgical complications were evaluated using the Clavien-Dindo classification. We also assessed the effect of the nutraceutical on gut microbiota composition, inflammatory response, nutritional status, and quality of life. A subanalysis based on surgery type (robotic vs. non-robotic) was performed. Results: We included 46 patients who met the inclusion criteria, with 27 randomized to the intervention group and 19 to the placebo group, receiving treatment for 3 [2–4] weeks. Non-robotic surgery was performed in 35 (76.1%) patients. We found non-significant differences in postoperative complications (Micodigest 2.0: 25.9%, placebo: 26.3%; p = 0.9). In non-robotic surgery, we identified a non-significant reduction in postoperative complications (Micodigest 2.0: 25.0%, placebo: 36.4%; p = 0.7), as well as a significant increase in lymphocyte levels and a reduction in the neutrophil-to-lymphocyte ratio (p = 0.02). Micodigest 2.0 supplementation was also associated with significant changes in gut microbiota composition, as indicated by a decreased relative abundance of the phyla Firmicutes (p = 0.004) and Actinobacteria (p = 0.04). Conclusions: Micodigest 2.0 supplementation was associated with non-significant reductions in postoperative complications and significant modifications in gut microbiota composition. Limitations: The trial did not reach the calculated sample size.