Table 1.

Eligibility criteria based on PICOS model

Items based on PICOS model	Eligibility criteria
1. Population or participants and conditions of interest	Humans, any age, diagnosed with colorectal cancer (CRC) or with colon cancer or rectal cancer and have been treated with probiotics as an intervention and this will include:
	Patients with CRC who have had colorectal surgery or colon resection or haven’t had surgery.
	Patients with CRC who had or are still undergoing chemotherapy or radiotherapy or not.
2. Interventions or exposures	Probiotics of any kind (eg, Lactobacillus, Bifidobacterium, Propionibacterium, Saccharomyces, etc) used on its own or in combinationwith other probiotics or combination with prebiotics such as inulin orresistant starch.
3. Comparisons or control groups	Placebos, or healthy people of any age, without CRC.
	Baseline comparison of patients before the intervention.
4. Outcomes of interest	Primary outcomes
	Effects of probiotics on the diversity of human gut microbiota.
	Effects of probiotics on inflammatory biomarkers relevant to CRC.
	Immunoregulatory action of probiotics.
	Secondary outcomes
	Patient status (improvement/ no improvement of colorectal carcinoma) after administration of probiotics.
	Prognosis such as imaging to compare the size of cancer tumour before and after intervention.
	General health and improvement in quality of life of the patient.
	Adverse events such as morbidity and mortality.
5. Study designs	Clinical trials, randomised clinical trials.
6. Other exclusion criteria	Articles not in English language.
	Reviews.
	Animal or in vitro work done with zprobiotics.
	Studies not about CRC or rectal or colon cancer.
	Studies not testing the role of probiotics on CRC or rectal or colon cancer patients.

PICOS model, P – Patient, Problem or PopulationI – InterventionC – Comparison, control or comparatorO – Outcome of interest S – Study type.