If a picture is worth a thousand words, take a good look at the picture: Survival after liver metastasectomy for colorectal cancer.

INTRODUCTION: An analysis of NHS data published in by Morris et al. in 2010 is widely used as evidence in support of liver metastasectomy for colorectal cancer and its wider application. Recent evidence concerning better overall survival for patients with metastatic colorectal cancer challenges the notional assumptions about what survival would be without metastasectomy. Earlier detection of metastases for local treatments has not resulted in a survival benefit.

MATERIALS AND METHODS: The interpretation of its central graphical display is critically reviewed and the common the limitations of the analysis of registry data and resulting immortal time bias are explored.

RESULTS AND DISCUSSION: Recent evidence, including the 2017 CLOCC trial report make the original interpretation of the analysis suspect. Randomised trials are essential to detect a treatment effect of specific interventions among variable disease progression, selection bias, and multiple and repeated treatments that are inherent in the management of advanced cancer.