To achieve an adequate visual working field during laparoscopic colorectal surgery without disturbance of the small intestine, patients are positioned in Trendelenburg position. This position results in hemodynamic changes which may increase the risk of cardiopulmonary complications and prolonged hospital stay. Recently, an intraoperative retractor sponge was introduced as alternative for the Trendelenburg position during laparoscopic surgery.

Objective: To study the impact of use of an intraoperative retractor sponge on duration of hospital stay and risk of perioperative complications in patients undergoing laparoscopic surgery for colorectal cancer.

Study design: Randomized controlled trial, nested within a prospective cohort according to the 'cohort multiple randomized controlled trial' (cmRCT) design (clinicaltrials.gov NCT02070146).

Study population: Patients with colorectal cancer who undergo laparoscopic sigmoid of rectal resection, and who have given informed consent to be offered experimental interventions within the prospective cohort. Patient who require open surgery or patients with benign colorectal diseases are excluded for this study.

Intervention: Intraoperative use of the retractor sponge versus usual care, i.e. the Trendelenburg position.

Main study parameters/endpoints: The primary endpoint is hospital stay. Secondary objectives are operation time, blood-loss, fluid balance, body temperature, oxygen therapy and postoperative complications.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The study will be conducted according to the cohort multiple Randomized Controlled Trial (cmRCT) design. Within the PLCRC cohort, we will identify all patients who are eligible for the experimental intervention and who have given informed consent to be invited for future experimental interventions. From this sub cohort, we will randomly select a group of patients to whom we will offer surgery with use of the retractor sponge, which they can accept or decline. Eligible patients from the sub cohort who were not randomly selected will undergo standard treatment, i.e. surgery in Trendelenburg position. We do not expect adverse events in patients in the intervention arm.

Inclusion Criteria:

1. histologically confirmed distal colon (sigmoid) or rectal cancer,
2. planned for elective laparoscopic colorectal surgery,
3. performance status WHO 0-2
4. broad consent for randomization within ProspectIve data coLlection initiative on ColoRectal Cancer (PLCRC) cohort

Exclusion Criteria:

1. patients planned for open colorectal surgery or emergency colorectal surgery
2. patients with inadequate understanding of the Dutch language in speech and/or writing.