The aim of this double-blinded prospective randomised trial is to explore the potential benefits of early postoperative administration of Synbiotics (combination of prebiotics and probiotics) to patients who have undergone colectomy for cancer. The patients are randomised to either synbiotics or placebo administration at the day they are able to tolerate po liquid diet and for 15 days thereafter.

Primary end points of the study will be:

Assessment of gastrointestinal function-related quality of life at 1, 3 and 6 months postoperatively by the use of the validated questionnaire GIQLI (Gastrointestinal Quality of Life Index)

Secondary end points will be:

-Assessment of functional bowel disorders (diarrhea, constipation, etc) at 1, 3 and 6 months postoperatively based on the respective domains of the validated instrument EORTC QLQ-C30

The study patients are randomized before surgery to receive either synbiotics (Synbiotics group) or placebo (Control group). Equal randomization is accomplished using a computer-generated random allocation schedule. The method of allocation concealment is sequentially numbered sealed opaque envelopes technique. Both synbiotics and placebo preparations are in foil-sealed sachets stored in identical numbered containers. Both study products are white powders, identical in weight, smell, and taste. Thus, the identity of the specific product is blind to participants, support staff and investigators for the entire duration of the study period.

Inclusion Criteria:

• Colectomy for histologically proven colorectal adenocarcinoma

Exclusion Criteria:

• Pregnancy,
• hereditary cancer,
• history of inflammatory bowel disease,
• metastatic disease at presentation,
• emergency operation,
• major postoperative complications