Systems mapping: a novel approach to national lung cancer screening implementation in Australia.

Background: Lung cancer screening with low-dose computed tomography has been started in some high-income countries and is being considered in others. In many settings uptake remains low. Optimal strategies to increase uptake, including for high-risk subgroups, have not been elucidated. This study used a system dynamics approach based on expert consensus to identify (I) the likely determinants of screening uptake and (II) interactions between these determinants that may affect screening uptake. Methods: Consensus data on key factors influencing screening uptake were developed from existing literature and through two stakeholder workshops involving clinical and consumer experts. These factors were used to develop a causal loop diagram (CLD) of lung cancer screening uptake. Results: The CLD comprised three main perspectives of importance for a lung cancer screening program: participant, primary care, and health system. Eight key drivers in the system were identified within these perspectives that will likely influence screening uptake: (I) patient stigma; (II) patient fear of having lung cancer; (III) patient health literacy; (IV) patient waiting time for a scan appointment; (V) general practitioner (GP) capacity; (VI) GP clarity on next steps after an abnormal computed tomography (CT); (VII) specialist capacity to accept referrals and undertake evaluation; and (VIII) healthcare capacity for scanning and reporting. Five key system leverage points to optimise screening uptake were also identified: (I) patient stigma influencing willingness to receive a scan; (II) GP capacity for referral to scans; (III) GP capacity to increase patients' health literacy; (IV) specialist capacity to connect patients with timely treatment; and (V) healthcare capacity to reduce scanning waiting times. Conclusions: This novel approach to investigation of lung cancer screening implementation, based on Australian expert stakeholder consensus, provides a system-wide view of critical factors that may either limit or promote screening uptake.