Irinotecan is one of key drug used in the treatment of colorectal cancer, but its toxic metabolite is associated with malabsorption and the development of diarrhea (Michael et al. 2004). It is known that probiotic bacteria reduce activity of intestinal beta-d-glucuronidase, and therefore these bacteria could be applied in the prevention of diarrhea in patients treated by this food supplement. Given their low toxicity and good tolerability, probiotics may be an important part of supportive therapy.

Randomized, double blind, placebo controlled pilot study suggest that administration of probiotic formula Colon DophilusTM compared to placebo is associated with reduction of gastrointestinal toxicity of irinotecan-based chemotherapy, and these results were consistent for all types of recorded gastrointestinal toxicity. Administration of probiotics compared to placebo led to a reduction in the incidence of severe diarrhea of grade 3 or 4 [0 % for probiotics vs. 17.4 % (95% CI 1.9–32.9 %), for placebo, p = 0.11], as well as reduction of the overall incidence of diarrhea [39.1 % (95 % CI 19.2–59.0 %) for probiotics vs. 60.9 % (95 % CI 41.0–80.8 %) for placebo, p = 0.24] and incidence of enterocolitis (0 % for probiotics vs. 8.7 % for placebo). Patients on placebo arm reported more often bloating compared to probiotic arm. Moreover, no infection caused by probiotic strains used in this study was observed. Although limited statistical power caused by lower sample size than expected, these data suggest probiotics could be simple, effective, and nontoxic approach to reduce gastrointestinal toxicity of irinotecan-based chemotherapy (Mego et al. 2015) (Table 1).

Administration of 5-fluorouracil, one of the key anticancer drugs in treatment of colorectal cancer, is associated not only with direct mucosal damage but also with development of lactose intolerance and diarrhea in duration-dependent manner. Lactobacillus rhamnosus GG supplementation reduced the frequency of severe diarrhea and abdominal discomfort related to 5-FU-based chemotherapy in the study with 150 colorectal cancer patients. Moreover, the probiotic administration was well tolerated, and none L. rhamnosus was identified in the blood cultures during the study (Osterlund et al. 2007).

Recently, the results from 11 randomized, controlled trials concerning on the efficacy of probiotics in people with cancer (N = 1557 participants) displayed reducing the severity and frequency of diarrhea in patients with cancer and the requirement for antidiarrheal medication, respectively. Meta-analysis found that probiotics significantly reduced incidence of CTC (Common Terminology Criteria for Adverse Events) grade ≥2 diarrhea (odds ratio 0.32, 95 % confidence interval, 0.13–0.79, PI 0.11–0.97, p = 0.01), but was unclear for CTC grade ≥3 diarrhea (odds ratio 0.72, 95 % CI of 0.42–1.25, 95 % PI of 0.41–1.27, p = 0.24) (Redman et al. 2014).