Patients (ASA class III and IV) with colorectal cancer were randomized in a double-blinded pilot study to: prophylaxis with G-CSF (12 hours before surgery, 12 and 36 hours after surgery) versus placebo. Measurements of G-CSF, IL-6, IL-18, Procalcitonin (PCT) in plasma, leukocyte count, percentage of polynuclear granulocytes (PMNs) and their phagocytic activity were started before operation and continued till day 6 after surgery. TNF-a release was determined after LPS in vitro stimulation of whole blood. All complications were documented as well as quality of life (QL) at discharge, 2 and 6 months after surgery using the EORTC QLQ 30 questionnaire and for global QL the index-points of the area under the curve (AUC) were calculated.