The management of peri-operative pain is one of the pillars of anaesthesia and is of particular importance in patients undergoing surgery for solid malignant tumours. Amongst several options, the most commonly employed analgesic regimens involve opioids, NSAIDs and regional anaesthesia techniques with different local anaesthetics. In recent years, several research reports have tried to establish a connection between peri-operative anaesthesia care and outcome after cancer surgery. Experimental studies have indicated that certain pain management substances may influence cancer progression, mainly by modifying the tumour's response to surgical stress and peri-operative inflammation. However, these promising in-vitro and in-vivo data have yet to be confirmed by randomised clinical trials. The reason for this might lie with the nature of tumour biology itself, and in the diversity of patient and tumour phenotypes. In a translational approach, future research should therefore concentrate on patient and tumour-related factors or biomarkers, which might either influence the tumour and its microenvironment or predict potential responses to interventions, including the choice of the analgesic. This might not only be relevant for the daily practice of clinical anaesthesia, but would also be of great importance for patients undergoing cancer surgery, who might be able to receive an individualised anaesthetic regimen based on their phenotypic profile.