Diagnosis of lung cancer in primary care: a structured review

Lung cancer has the highest cancer incidence and mortality in the UK. Despite this, an individual GP encounters only one new presentation approximately every 8 months, so gains relatively little experience of its diagnosis. This is partly addressed by referral guidelines which aim to help GPs in selection of patients for chest X-ray or referral for specialist investigation.

The purpose of this study was to review the primary care presenting features of lung cancer, in the light of the UK Referral Guidelines for Suspected Cancer.

A structured literature review was carried out.

Little research has been undertaken in primary care, and the predictive values for most symptoms are unknown. Approximate likelihood ratios could be calculated for six symptoms or signs: haemoptysis 13; fatigue 5.7; cough 5.3; finger clubbing 3.9; weight loss 2.9; and dyspnoea 1.5-5.7, but none of these figures derived from single primary care studies. Three recommendations for urgent investigation of possible lung cancer in the UK Referral Guidelines are questioned: for unexplained dyspnoea, hoarseness or cervical lymphadenopathy. For all these presentations, other serious diagnoses are more likely.

The UK Guidelines for referral of suspected lung cancer have a weak evidence base.