Conventionally, patients with acute left-sided malignant colonic obstruction are treated with emergency surgery to restore luminal patency. These emergency operations have a mortality rate of 15-34% and a morbidity rate of 32-64% despite advances in perioperative care. Since the early 1990s, colonic stenting has been introduced, mainly in the left-sided colon, to restore luminal patency. In uncontrolled studies, stent placement before elective surgery has been suggested to improve the patient's clinical condition, thus decreasing mortality, morbidity, and the number of colostomies. To date, only one randomised controlled trial has been published: this study had several limitations, due to which there is still insufficient evidence. Therefore, a large-scale comparison between these two treatment algorithms has been initiated in a prospective multicentre randomised setting with respect to quality of life, morbidity, mortality, and healthcare costs.