Diagnosis of cancer is a complex, multi-step process. This presentation will highlight factors involved in missed opportunities to diagnose cancer more promptly in symptomatic patients and discuss responsible mechanisms and potential strategies to shorten intervals from presentation to diagnosis. Topics will include discussion of definitions and measurements of missed opportunities, i.e. instances in which post-hoc judgement indicates that alternative decisions or actions could have led to more timely diagnosis. Opportunities to improve all three phases of the diagnostic process (initial diagnostic assessment; diagnostic test performance and interpretation; and diagnostic follow-up and coordination) will be highlighted. Discussions will involve multifaceted ways in which patient, doctor/care team, and health-care system factors, could be addressed to reduce preventable delays in cancer diagnosis.