Introduction Most people with lung cancer in the UK are diagnosed late when curative treatment is no longer an option. This research aimed to determine the pattern of symptom reporting to GPs before lung cancer diagnosis to establish whether there is potential for developing a scoring system to allow cases to be diagnosed earlier.

Methods We used data from The Health Improvement Network (THIN)—A computerised longitudinal primary care database. We identified 12 121 incident cases of lung cancer diagnosed between 2000 and 2009 and matched each case with up to four controls by age, sex and general practice (n=48 216). Conditional logistic regression was carried out to estimate the ORs for symptoms 2 years before and 1 year before lung cancer diagnosis in cases compared to controls.

Results A sharp increase in the consultation frequency among lung cancer cases was found for cough, haemoptysis, chest/shoulder pain, voice hoarseness, dyspnoea, weight loss, lower respiratory tract infections, non-specific chest infections and chronic obstructive airway disease, about 9 months before they were diagnosed with lung cancer. The highest OR in cases compared to controls at 1 year was noted for haemoptysis (OR 54.7, 95% CI 42.5 to 70.4) and the lowest was for upper respiratory tract infections (OR 1.72, 95% CI 1.55 to 1.92).

Conclusions Patients with lung cancer have an increase in reporting of symptoms to the GP which occurs about 9 months before they are diagnosed. Future work will aim to develop these results into a predictive score to allow earlier diagnosis of lung cancer.