TY - JOUR T1 - Estimating lung cancer risk from chest X-ray and symptoms: a prospective cohort study JF - British Journal of General Practice JO - Br J Gen Pract SP - e280 LP - e286 DO - 10.3399/bjgp20X713993 VL - 71 IS - 705 AU - Stephen H Bradley AU - Nathaniel Luke Fielding Hatton AU - Rehima Aslam AU - Bobby Bhartia AU - Matthew EJ Callister AU - Martyn PT Kennedy AU - Luke TA Mounce AU - Bethany Shinkins AU - William T Hamilton AU - Richard D Neal Y1 - 2021/04/01 UR - http://bjgp.org/content/71/705/e280.abstract N2 - Background Chest X-ray (CXR) is the first-line investigation for lung cancer in many countries but previous research has suggested that the disease is not detected by CXR in approximately 20% of patients. The risk of lung cancer, with particular symptoms, following a negative CXR is not known.Aim To establish the sensitivity and specificity of CXR requested by patients who are symptomatic; determine the positive predictive values (PPVs) of each presenting symptom of lung cancer following a negative CXR; and determine whether symptoms associated with lung cancer are different in those who had a positive CXR result compared with those who had a negative CXR result.Design and setting A prospective cohort study was conducted in Leeds, UK, based on routinely collected data from a service that allowed patients with symptoms of lung cancer to request CXR.Method Symptom data were combined with a diagnostic category (positive or negative) for each CXR, and the sensitivity and specificity of CXR for lung cancer were calculated. The PPV of lung cancer associated with each symptom or combination of symptoms was estimated for those patients with a negative CXR.Results In total, 114 (1.3%) of 8996 patients who requested a CXR were diagnosed with lung cancer within 1 year. Sensitivity was 75.4% and specificity was 90.2%. The PPV of all symptoms for a diagnosis of lung cancer within 1 year of CXR was <1% for all individual symptoms except for haemoptysis, which had a PPV of 2.9%. PPVs for a diagnosis of lung cancer within 2 years of CXR was <1.5% for all single symptoms except for haemoptysis, which had a PPV of 3.9%.Conclusion CXR has limited sensitivity; however, in a population with a low prevalence of lung cancer, its high specificity and negative predictive value means that lung cancer is very unlikely to be present following a negative result. Findings also support guidance that unexplained haemoptysis warrants urgent referral, regardless of CXR result. ER -