Background: Potentially avoidable diagnostic delays in primary care may contribute to Ireland’s poorer cancer outcomes compared with similar countries, yet specific, measurable mechanisms have not been quantified in Irish general practice. International primary care studies report three reproducible signals of delayed diagnostic opportunity: (i) escalation of antibiotics and other respiratory prescribing before lung cancer diagnosis; (ii) higher cancer risk across platelet strata, including the upper “”high-normal”” range; and (iii) prolonged intervals between abnormal PSA results and clinical action. These findings have not been replicated in Ireland. In parallel, Ireland lacks the analytical infrastructure and standardised protocols required to participate in distributed international cancer benchmarking collaborations such as ICBP, which increasingly use primary care datasets in participating jurisdictions.
Aims: (1) Quantify and benchmark three established diagnostic delay mechanisms in Irish primary care by replicating validated international studies and comparing estimates with published UK and Australian results; (2) develop OMOP-based, OHDSI-compatible protocols enabling Ireland’s participation in distributed international primary care studies without transfer of patient-level data.
Methods: Retrospective analyses using CRADLE (~1.5 million Irish general practice records). We will replicate: (i)Wickramasinghe et al. (2023): trajectories of antibiotic, inhaler and oral steroid prescribing in the 12 months before lung cancer diagnosis versus matched controls; (ii) Mounce et al. (2020): age- and sex-specific 12-month cancer incidence and positive predictive values across platelet categories, including 350–399×10⁹/L and ≥400×10⁹/L; (iii) Wawryk et al. (2025): time from PSA >3 ng/mL to first clinical action (repeat testing, referral or biopsy), stratified by public(GMS) versus private pathways where identifiable. We will publish version-controlled OHDSI cohort definitions and analysis code with implementation guidance.
Expected results: Irish diagnostic quality benchmarks for NCCP guideline updates; operational capacity for Ireland’s participation in international primary care studies(e.g. ICBP Phase 3); reusable open-source protocol library supporting ongoing distributed cancer research without data sharing barriers.