Granulocyte-colony stimulating factor in the prevention of postoperative infectious complications and sub-optimal recovery from operation in patientswith colorectal cancer and increased preoperative risk (ASA 3 and 4) - Protocol for a controlled clinical trial developed by consensus of an international study group - Part two: design of the study

General design: Presentation of a new type of a study protocol for evaluati on of the effectiveness of an immune modifier (rhG-CSF, filgrastim): preven tion of postoperative infectious complications and of sub-optimal recovery from operation in patients with colorectal cancer and increased preoperativ e risk (ASA 3 and 4). This part describes the design of the randomised, pla cebo controlled, double-blinded, single-centre study performed at an univer sity hospital (n = 40 patients for each group). Objective: The trial design includes the following elements for a prototype protocol: The study population is restricted to patients with colorectal cancer, incl uding a left sided resection and an increased perioperative risk (ASA 3 and 4). Patients are allocated by random to the control or treatment group. The double blinding strategy of the trial is assessed by psychometric indic es. An endpoint construct with quality of life (EORTC QLQ-C30) and a recovery i ndex (modified Me Peek index) are used as primary endpoints. Qualitative an alysis of clinical relevance of the endpoints is performed by both patients and doctors. Statistical analysis uses an area under the curve (AUC) model for improveme nt of quality of life on leaving hospital and two and six months after oper ation. A confirmatory statistical model with quality of life as the first p rimary endpoint in the hierarchic test procedure is used. Expectations of p atients and surgeons and the negative affect are analysed by social psychol ogical scales. Conclusion: This study design differs from other trials on preoperative pro phylaxis and postoperative recovery, and has been developed to try a new co ncept and avoid previous failures.