Table 1

Time point definitions based on the ‘Aarhus Statement’28

Date of first symptom	The time point when first bodily changes and/or symptoms are noticed. Should encompass several key components: the date when the first bodily change was noticed, the date when the first symptom was noticed, the date when the person perceives a reason to discuss the symptom with a healthcare professional and the date when the first ‘alarm’ or ‘high-risk’ symptom was noticed.
Date of first presentation	The time point at which, given the presenting signs, symptoms, history and other risk factors, it would be at least possible for the clinician seeing the patient to have started investigation or referral for possible important pathology, including cancer.
Date of referral	The time point at which there is a transfer of responsibility from one healthcare provider to another (typically, in ‘gatekeeper’ healthcare systems, from a primary care provider to a doctor/service specialising in cancer diagnosis and management) for further clinical diagnostic and management activity, relating to the patient's suspected cancer. Patients may be referred more than once or between specialists.
Date of diagnosis	Studies should be explicit about how the date is measured, and should consult the well-developed hierarchical rationales available in the public domain in choosing their definition of date of diagnosis.