Cancer care operates as a complex adaptive system, and thus, by definition the way we interrogate our cancer systems and shape them through public policy necessitates a systems approach. But what does this really mean for the front line services? How do a system approaches (dis)connect policy-makers from the stochastic nature of clinical care. In this lecture we'll discuss some of the foundations of systems thinking, how this differs from other models and whether this can ever truly reflect the 'ground'. Drawing on data from studies of the economics of cancer, the epidemiological of cancer and behavioral ecology of healthcare systems we'll critically examine the case for and against thinking and planning cancer care as a system. Looking more widely across the global landscape how much can a systems approach help us understand and improve patient outcomes in such vastly national contexts and settings. Lastly we'll ask whether our current policies and paradigms have become victims of the 'two cultures' problem and how single interest(s) can distort public health priorities in cancer.