RESUMO
PURPOSE: Diarrhea is one of the dose limiting toxicity of irinotecan. SN-38 is main irinotecan metabolite responsible for diarrhea development, which is excreted in glucuronidated form into the intestine. This study aimed to determine the effectiveness of the probiotics in the prevention of irinotecan induced diarrhea due to reduction of intestinal beta-d-glucuronidase activity. METHODS: Between January 2011 and December 2013, 46 patients with colorectal cancer starting a new line of irinotecan based therapy were included. Patients were randomized 1:1 to probiotics (PRO) or placebo (PLA). Probiotic formula Colon Dophilus™, was administered at a dose of 10×10(9)CFU of bacteria tid, orally for 12 weeks of chemotherapy. The study was prematurely terminated due to slow accrual, when 46 of 220 planned patients were accrued. RESULTS: Twenty-three patients were randomized to PRO and 23 patients to PLA. Administration of probiotics compared to placebo led to a reduction in the incidence of severe diarrhea of grade 3 or 4 (0% for PRO vs. 17.4% for PLA, p=0.11), as well as reduction of the overall incidence of diarrhea (39.1% for PRO vs. 60.9% for PLA, p=0.24) and incidence of enterocolitis (0% for PRO vs. 8.7% for PLA). Patients on PRO used less antidiarrheal drugs compared to PLA. There was no infection caused by probiotic strains recorded. CONCLUSIONS: Administration of probiotics in patients with colorectal cancer treated with irinotecan-based chemotherapy is safe and could lead to a reduction in the incidence and severity of gastrointestinal toxicity.