Lower gastrointestinal symptom burden by prophylaxis with synbiotics after colorectal cancer surgery (LEONORA)

A key component of colorectal cancer treatment is the surgical resection of the tumor accompanied by antibiotic treatment and often chemotherapy, which severely challenge the gut microbiome. Thus, colorectal cancer patients commonly suffer from gastrointestinal symptoms like chronic diarrhea, which can persist in some patients for several years.

Synbiotics are a mixture comprising live microorganisms and substrate(s) selectively utilized by host microorganisms that confer a health benefit on the host. Previous trials have shown that synbiotics reduce rates of post-operative infections and related complications, diarrhea incidence, and inflammation. However, data on the gastrointestinal quality of life and potential improvement of the survival time are very sparse.

The LEONORA trial is a trial with 206 colorectal cancer patients, who shall be recruited in 10 German hospitals. While 103 patients in arm 1 will be randomly selected to receive a placebo, 103 patients in arm 2 will be randomly selected to receive a daily synbiotic treatment for 12 weeks with 50 billion colony-forming units of 12 live bacterial strains. After the wound healing phase, patients in the intervention arm will additionally receive the dietary fiber inulin in weeks 5-12, which acts as a substrate because it is broken down by the administered bacterial strains and contributes to their proliferation in the intestine. Every 2 weeks, the inulin dosage will be stepwise increased from 3 g to 10 g per day to slowly train the gut microbiome and avoid flatulence.

The study participants in the placebo group, on the other hand, receive maltodextrin as a second placebo, which is very similar to inulin in appearance and taste, but has no effect on the gut microbiome.

The detailed study description can be found in the German Clinical Trials Register.