Ready to screen implementation trial protocol: a cluster randomized implementation trial comparing a bundled implementation strategy versus a simple implementation strategy to improve intention to screen in the Australian National Lung Cancer Screening Program

Uptake of lung cancer screening (LCS) in high-risk populations remains suboptimal internationally. Primary care practitioners play a critical role in identifying eligible patients and initiating referrals for LCS. Targeted implementation strategies are needed to address health care barriers to the uptake of LCS such as limited awareness, eligibility assessment, low engagement, and poor health system preparedness. Implementation trials are needed to determine optimal decision-making and participant knowledge gains to ultimately increase screening uptake. The Ready to Screen trial is a cluster randomized controlled implementation trial to compare participants’ intention to screen for lung cancer in the Australian National Lung Cancer Screening Program (hereafter ‘the Program’) between bundled (intervention: core + link to multilingual trial website + SMS and email reminders, clinical decision support prompts for general practitioners) and core (control (core): initial letter mail out with LCS brochure only) implementation strategies. Twenty-eight general practices recruited across Australia will be randomly allocated (1:1 ratio) to either control or intervention. Practices will generate eligible patient lists using medical records to issue participation invitations. Eligible patients are aged 50–70 years and currently smoke or have quit within the past 10 years or have an unknown quit date. The primary outcome is participant intention to screen from self-report survey at patient recruitment. Secondary outcomes will be evaluated using the RE-AIM framework—examining Reach, Effectiveness (including cost-effectiveness), Adoption, Implementation and Maintenance. The PRISM framework will guide assessment of multi-level contextual factors hypothesized to influence these outcomes. Data collection will include trial recruitment and practice records, participant and provider self-report surveys, and semi-structured interviews. This trial will generate timely evidence about the effectiveness and cost-effectiveness of the bundled implementation strategy to support delivery of the Program within primary care practices. Findings will provide insights into contextual factors shaping implementation success and inform the future scaling and sustainability of LCS in Australia and internationally. ACTRN12625000045415 registered on 20/01/2025.