A new diagnosis of cancer is rare in primary care, and the role of general practitioners (GPs) in diagnosing cancer can be challenging. In the United Kingdom, a GP with a list size of 1500 will on average see only 1.39 cases of lung cancer, 0.23 oesophageal cancers, 0.99 colorectal cancers, and 0.45 renal or bladder cancers each year.1 We seek to diagnose the few patients with cancer out of the many who are concerned about it or who have non-specific problems. In this week's BMJ, a cohort study by Jones and colleagues assesses the association between alarm symptoms and a subsequent diagnosis of cancer in just under 800 325 patients in primary care.2

Diagnostic errors are one of the leading causes of medicolegal claims against GPs,3 and they can damage the faith of our patients. However, we have a role as gatekeepers of health resources and more recently the added responsibility of managing a budget. Over-referral to secondary care can unnecessarily raise patients' anxiety while awaiting investigation and waste precious resources.

What are we to make of alarm symptoms? Are certain symptoms or …