3. Probiotics vs active treatment for prevention of diarrhoea induced by radiotherapy (with or without chemotherapy).

Study ID and participants	Intervention(s)	Results
Osterlund 2007 Participants with Dukes' B or C colorectal cancer or metastatic colorectal cancer who underwent chemotherapy and radiotherapy	Intervention:Lactobacillus rhamnosus GG (administered orally as gelatin capsules twice daily at a dose of 1 to 2 × 10¹º per day during 24 weeks of adjuvant cancer chemotherapy (n = 98) Control: guar gum containing nutritional supplement (contains 11 g guar gum and 550 kcal or 2300 kJ), administered daily, on cycle days 7 to 14, for 8 days per month (n = 52) All participants received dietary counselling	Proportion of participants with diarrhoea: not reported Quality of life: not assessed Severity of diarrhoea: grade 3‐4 OR 0.38 (95% CI 0.16 to 0.89) Time to rescue medication for diarrhoea: not assessed Proportion of participants requiring rescue medication for diarrhoea: not assessed Adverse events (Common Toxicity Criteria of the National Cancer Institute of Canada scale version 2): Any adverse event grade 3 or 4: OR 0.77 (95% CI 0.35 to 1.72) Stomatitis grade 3 or 4: OR 0.59 (95% CI 0.26 to 1.35) Neutropenia grade 3 or 4: OR 2.00 (95% CI 0.74 to 4.89) Neutropenic infection grade 3 or 4: OR 2.62 (95% CI 0.53 to 13.00) Hand‐foot syndrome grade 3: 2/97 versus 1/51 (OR: no convergence) Mortality: study authors reported no deaths
Salminen 1988 Participants with carcinoma of the cervix or uterus who were to receive radiotherapy	Intervention: dietary counselling recommending a low‐fat and low‐residue diet during radiotherapy and a daily dose of at least 2 × 10⁹ live Lactobacillus acidophilus bacteria in the form of a yogurt‐type product (150 mL of a fermented milk test product) and 6.5% lactulose as substrate for the bacteria; 150 mL of the product daily for 5 days before radiotherapy, daily throughout the radiotherapy period including the interval, and then for 10 days after completion of the therapy regimen (n = 12) Control: dietary counselling only recommending a low‐fat and low‐residue diet during radiotherapy (n = 12)	Proportion of participants with diarrhoea: "All subjects in the control group suffered from diarrhoea during the radiotherapy" During treatment, control time 2: 3/11 versus 8/10 (RR 0.34, 95% CI 0.12 to 0.94) During treatment, control time 3: 2/11 versus 9/10 (RR 0.20, 95% CI 0.06 to 0.72) During treatment, control time 4: 2/11 versus 8/10 (RR 0.23, 95% CI 0.06 to 0.83) Six weeks after treatment: 3/11 versus 9/10 (RR 0.30, 95% CI 0.11 to 0.81) "The incidence of diarrhoea was significantly smaller in the yoghurt group than in the control group (P<0.01)" Quality of life: not assessed Severity of diarrhoea: not assessed Time to rescue medication for diarrhoea: not assessed Proportion of participants requiring rescue medication for diarrhoea: 2/11 versus 6/10 (RR 0.30, 95% CI 0.08 to 1.17) Adverse events: "There were no differences in the incidence of vomiting, nausea, abdominal pain, loss of appetite or weight loss between the groups. However, the yoghurt group experienced more flatulence than the controls" Mortality: study authors reported no deaths
Timko 2010 Participants with cancer who underwent adjuvant postoperative radiotherapy therapy in the abdominal and pelvic region, with or without chemotherapy	Intervention: probiotic preparation "5"‐strain Dophilus (55% Lactobacillus rhamnosus, 20% Bifidobacterium adolescentis, 5% Lactobacillus acidophilus, 5% Bifidobacterium longum, 15% Enterococcus faecium) with a count of 6 billion active bacteria/capsules at a daily dosage of 2 × 1 capsule (n = 22) Control: Hylak Tropfen Forte preparation (i.e. cell‐free fermentation products of Lactobacillus helveticus and gut symbionts (100 mL containing: 24.95 g Escherichia coli metabolita, 12.5 g Streptococci faecalis metabolita, 12.5 g Lactobacillus acidophilus metabolita, 49.9 g Lactobacillus helveticus metabolita) in doses of 40 drops, 3 times per day (n = 20)	Proportion of participants with diarrhoea: not assessed Quality of life: not assessed Severity of diarrhoea: not assessed Time to rescue medication for diarrhoea: not assessed Proportion of participants requiring rescue medication for diarrhoea (diphenoxylate): RR 0.50, 95% CI 0.23 to 1.09 Adverse events: Abdominal pain: 25% versus 22% "All these participants were being treated with pelvic radiotherapy with chemotherapy, except for one patient of L‐Group. Chemotherapy thus seemed to result in increased toxicity" "None of the participants discontinued treatment for gastrointestinal toxicity" Mortality: study authors reported no deaths

CI: confidence interval.

OR: odds ratio.

RR: risk ratio.