title: Negative chest X-rays in primary care patients with lung cancer.
abstract: BACKGROUND
  The main investigation for suspected lung cancer in primary care is a chest X-ray. Reports from secondary care show that some patients with normal chest X-rays transpire to have lung cancer. The assumption is that this occurs rarely in primary care.
  
  
  OBJECTIVE
  The aim of this study was to examine the frequency of misleading chest X-rays in primary care, and whether there were any particular symptoms associated with them.
  
  
  METHODS
  Retrospective cohort study of the primary care records of 247 lung cancer patients diagnosed between 1998-2002.
  
  
  METHODS
  All general practices in Exeter Primary Care Trust, Devon, UK.
  
  
  METHODS
  All chest X-rays and all common symptoms of lung cancer reported to primary care were identified from the medical records. X-ray results were categorised into three groups by the radiologist's report: normal; abnormal but no malignancy suspected (together classified as negative X-rays); or abnormal with possible malignancy.
  
  
  RESULTS
  Of the 247 patients, 164 (66%) had a chest X-ray taken in primary care during the year before diagnosis: 126 of these (77%) were abnormal with possible malignancy; 21 (13%) were abnormal but with no malignancy suspected; in 17 (10%) the X-ray was reported as normal. Thus, 38 of 164 patients (23%; 95% confidence interval = 16 to 32%) had a negative X-ray. Negative X-rays were less common in the 90 days before diagnosis. No particular symptoms were significantly associated with negative X-rays.
  
  
  CONCLUSIONS
  Nearly a quarter of chest X-rays requested from primary care in lung cancer patients are negative. Further investigation is warranted with continuing or changing symptoms, even if the X-ray is not suggestive of malignancy.
authors.affiliation: CAPER research practices, Exeter.
authors.forename: Sally
authors.initials: S
authors.lastname: Stapley
authors.forename: Deborah
authors.initials: D
authors.lastname: Sharp
authors.forename: William
authors.initials: W
authors.lastname: Hamilton
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005188:False Negative Reactions; D005194:Family Practice; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012017:Referral and Consultation; D012189:Retrospective Studies