"One of the hardest things in medicine is challenging an initial diagnosis." Interim Diagnoses and Missed Opportunities for Diagnosing Cancer in Primary Care: A Qualitative Study.

Background Patients later diagnosed with cancer may first be diagnosed with another 'interim' diagnosis based on their clinical presentation. In some cases, interim diagnoses may be missed opportunities to diagnose cancer. Aim To explore healthcare professionals' perspectives of when interim non-cancer diagnoses occur, how they impact a cancer diagnosis, and what could trigger their prompt review. Design and setting Interviews were conducted between March and November 2024 with 35 General Practitioners (GPs), 3 other clinicians, and 3 practice administrators from 31 general practices in Southern England, UK. Method Semi-structured interviews via videocall. Interviews were analysed using Framework Analysis. Results Participants reported that interim diagnoses occurred in cases of diagnostic uncertainty, especially when non-specific symptoms were attributed to common differential diagnoses. Remote consultations were thought to increase the likelihood of interim diagnosis by limiting information gathering. Interim diagnoses were suggested to delay cancer diagnoses, although this was not always seen as avoidable. Clinicians hoped to facilitate opportunities to make a cancer diagnosis by using safety-netting to encourage reattendance, and an informal rule of "three strikes and you're in". Colleagues providing a "fresh pair of eyes", discussing diagnostic uncertainty in the clinical team, and using past cases as learning opportunities were suggested approaches to facilitate prompt review of interim diagnoses. Conclusion Consistent safety-netting is required to ensure timely review of non-cancer 'interim' diagnoses when there is a possible underlying cancer diagnosis. The range of interim diagnoses and their impact on cancer diagnosis requires further quantification to inform interventions to mitigate their effect.