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Centre for Evidence-
Based Medicine

Diagnosis: Clinical Scenario

As the leader of a new primary care group, you notice in your Health Authority's annual report a steady rise in rates of death from skin cancer, perhaps because people are spending more holidays in sunnier climes. As most forms of skin cancer are preventable if detected early, you wonder whether your GPs have sufficient diagnostic skills for what used to be a rare condition, but which now has a prevalence ("pretest probability") of about 5%. You formulate the question: "In patients with a skin lesion, how accurate are general physicians at diagnosing skin cancer?"

You open Best Evidence, enter "skin cancer" and click on the diagnosis limit button, and find the abstract for a study comparing the accuracy of clinical examinations conducted by GPs with those of dermatologists. You review the abstract and decide you'd like to read the complete article. Arch Intern Med 1997;157:985-990.

Read the article and decide:

  1. Are the results of this diagnostic article valid?
  2. Are the valid results of this diagnostic study important?
  3. Can you apply this valid, important evidence about a diagnostic test in caring for your patient or population?

Continue to completed worksheet