Approximately 13% (range 8-28%) presents with acute obstructing colorectal cancer (CRC). It's known that patients with acute obstructing CRC have increased mortality and morbidity compared to patients without acute obstructing CRC. Postoperative mortality ranges from 12 to 30%, which can raise to 41% in elderly patients with two or more additional risk factors. Morbidity rates until 78% are described in older patients undergoing emergency resection for obstructing CRC.

Different treatment options have been evaluated over the years. The two main options are; 1) emergency resection, simultaneous treatment of obstruction and tumour resection, 2) staged treatment of the obstruction with secondary resection of the tumour. Postoperative mortality after an emergency resection is known for its high risk of morbidity and mortality. From the Dutch audits it is know that the risk is high, not only for left sided obstruction, but also for right sided obstruction. Until recently, an acute emergency resection was the standard treatment for patients presenting with a small bowl ileus caused by a right sided colon cancer. However, more evidence has emerged that postponing surgery with a bridge tot surgery protocol can be beneficial to the patients. The bridge to surgery approach encompasses the utilization of either ileostomy creation or stent placement for colonic decompression, which is subsequently followed by definitive surgical treatment at a later stage. Alternatively, BTS may involve the introduction of a pause, also known as preoptimization, prior to the surgical procedure. The three main options for staged surgery all have its own up- and downsides. All forms of staged treatment appears to lead to fewer morbidity and mortality.

Emergency surgery Emergency resection is associated with a high risk of mortality and morbidity. Besides that, stoma creations after emergency surgery are higher than in patients treated electively. In case of a Hartmann's procedure, (resection of a left-sided tumour and creation of a colostomy) second surgical procedure is needed to restore continuity. Continuity restore has a mean mortality of 1% (range 0-7.4%) and morbidity of 16% (range 3-50%). Alternatively, emergency resection with primary anastomosis, which has the advantage to be a definite procedure, is performed. However, this treatment can be complicated with anastomotic leakage (AL). Anastomotic leakage is higher in patients treated for obstructing CRC in comparison with staged or electively treatment. Besides that, mortality rates after anastomotic leakage after colorectal surgery varies between 5-19%. Therefore, this intervention does not align with existing treatment strategies.

Bridge to surgery Stoma creation for colonic decompression followed by definite surgical treatment in a later stadium for patients with obstructing right sided CRC is an alternative. Postoperative mortality between patients treated with emergency resection, stent or stoma followed by resection showed no differences. However, high mortality rates in elderly patients (30%) after acute resection, stress the need for alternative strategies. For right-sided colon cancer, postoperative complications for patients treated with decompressing stoma before resection are lower in comparison with acute resection. However, the creation of an ileostomy leads to a longer hospital stay. Secondly, stenting as a bridge to surgery (BTS) creates time before definite surgical treatment. However, the use of stents as a bridge to surgery has controversial results. Stents as a BTS is associated with complications like perforation, stent migration, higher recurrence rate and re-obstruction. Furthermore, three prospective trials are closed prematurely because of high morbidity rates or a high number of technical failure of the self-expandable metallic stent (SEMS) However, several studies and one meta-analysis show promising short-term outcomes for the use of stents as BTS. Besides that, promising long-term outcomes, such as oncological safety, after stents as BTS are shown. Finally, transtumoral intubation for decompression of the colon, before initial can be considered to prevent stoma creation. Thirdly, a bridge to surgery may involve the introduction of a pause, also known as preoptimization, prior the surgical procedure. This previously presented as PRE-OCC, this approach appears feasible and safe. Deteriorating physical condition caused by poor intake, vomiting, changes in electrolyte status and weight loss often results in a decreased nutritional status. Nutritional status and thereby the patients preoperative health status seems to influence the mortality risk for patients with (obstructing) colorectal cancer. Creating a pause, before surgery provides a chance to optimise the patients' medical condition, perform a complete pre-operative screening of the patient's health status and examine possible concomitant illnesses. Besides nutritional status, also the functional capacity of the patient seems to be an important factor in postoperative mortality and morbidity. Studies, in elective colorectal surgery, show promising results after improving the functional capacity of patients (prehabilitation) on the recovery after colorectal surgery. However, this third option of bridge to surgery also has some disadvantages. Preoptimization leads to an prolonged duration of stay prior to surgery in a semi acute setting, with a central venous line and potentially insufficient decompression.

This study aims to determine whether implementation of bridge to surgery protocols is feasible and reduces mortality- and morbidity (stoma rates, major- and minor complications) rates in potentially curable patients presenting with acute obstructing CRC. By prospectively collecting the data, the feasibility of the protocols will be reported and the decrease in mortality and morbidity rates can be evaluated.