Pre-diagnostic primary care consultations and imaging in emergency-diagnosed vs referred lung cancer patients

Background Emergency diagnosis of lung cancer is common and associated with worse prognosis. Aim To compare pre-diagnostic healthcare use between emergency-diagnosed and patients referred routinely or urgently. Design and Setting We analysed population-based linked English primary care, hospital admission, imaging, and cancer registration data on patients with lung cancer (2007–2018). Methods We measured monthly pre-diagnosis rates of consultations (for any clinical reason and selected symptoms) and chest imaging by diagnostic route (emergency, routine referral, urgent referral. Multivariable Poisson regression estimated route-specific event rates and inflection points. Results We examined 4,473 patients with lung cancer with features representative of the nationwide incident cohort, of whom 33% (n=1,491) were emergency-diagnosed. Nearly all patients (98%) had consulted in primary care in the year pre-diagnosis, independently of diagnostic route. Consultation and imaging rates increased from 5- and 4-months pre-diagnosis, respectively, with shorter diagnostic windows in emergency-diagnosed than referred route patients. Compared with emergency-diagnosed, referred route patients had higher pre-diagnostic consultations rates for cough (adjusted Incidence Rate Ratio [aIRR] compared with emergency-diagnosed:1.90 for routinely and 1.94 for urgently referred patients) and chest X-ray use (aIRR:1.91 and 1.77, respectively). Conclusion Similar or shorter diagnostic windows suggest similar potential for earlier diagnosis among emergency-diagnosed and referred route patients alike. Earlier detection may be supported through improved management of non-specific symptoms, timely follow-up of imaging, and greater access to chest CTs. Future research should measure missed diagnostic opportunities to identify clinical actions to further reduce emergency lung cancer diagnoses. Keywords Cancer diagnosis; Primary care; Lung; Consultations; Emergency; Referral.