Efficacy and Safety of Probiotics as Adjunctive Therapy in Cancer Treatment: A Comprehensive Systematic Review and Meta-Analysis.

Objectives: The gut microbiome is crucial in influencing cancer progression and response to treatment. We evaluate the efficacy and safety of probiotics and synbiotics in cancer treatment, focusing on the incidence of diarrhea, significant complications, surgical site infections, length of hospital stay, progression-free survival (PFS), and overall survival (OS).

Methods: Following PRISMA guidelines, a comprehensive literature search was conducted in PubMed, Scopus, Web of Science, and Cochrane CENTRAL up to June 2024. The risk of bias was assessed using the Cochrane Risk-of-Bias tool. Meta-analysis was performed using a random-effects model.

Results: Fifteen studies involving 2197 participants were included. Probiotic use was associated with a significant reduction in the incidence of diarrhea (OR=0.39, 95% CI: 0.15-1.00, P=0.049) with moderate heterogeneity (I2=64%). No significant differences were found in major complications (OR=0.50, 95% CI: 0.05-4.92, P=0.4053, I2=73%), surgical site infections (OR=0.36, 95% CI: 0.12-1.09, P=0.058, I2=0%), length of hospital stay (SMD=-0.30, 95% CI: -1.00 to 0.41, P=0.2726, I2=62%), PFS (HR=0.61, 95% CI: 0.03-10.82, P=0.2715, I2=0%), or OS (HR=0.52, 95% CI: 0.00-58.82, P=0.3298, I2=0%).

Conclusions: Probiotics significantly reduced the incidence of chemotherapy-induced diarrhea, highlighting their potential as supportive care agents in oncology. However, their impact on significant complications, surgical site infections, length of hospital stay, and survival outcomes remains inconclusive.