One of the challenges in cancer treatment is catching the disease in the first place. Traditionally, chest X-rays are used to screen for lung cancer, but some have suggested that a low-dose CT scan might work better. Part of using a new diagnostic test is figuring out what to do with the results; researchers involved in a larger study of lung cancer screening looked at how doctors follow up on a CT scan that comes back positive.

What the researchers wanted to know: What do doctors do when a patient's low-dose CT scan shows something that could be lung cancer?

What they did: The patients were part of the Lung Screening Study, for which more than 3,300 smokers and former smokers were randomly assigned to get either low-dose spiral computed tomography (LDCT) or a chest X-ray. If they tested positive, they were told to go to their regular doctors. For this study, the researchers sought out medical records for everyone who'd had a positive LDCT screen.

What they found: Twelve percent of people who'd tested positive in their first lung cancer screen had a biopsy; an additional 55 percent had a CT scan of the chest. Three percent had no follow-up at all, and an additional 16 percent of the patients had a doctor only examine them or only compare the new results with those of an earlier chest X-ray or CT scan.

What the study means to you: Doctors may need more guidance on what to do with positive results from this test.

Caveats: The researchers didn't look at variables such as whether people had health insurance and what kind of doctor they went to see, which could add more useful information to these results.

Find out more: Information about the larger lung screening study, from the National Cancer Institute

Read the article: Pinsky, P. F., et al. "Diagnostic Procedures After a Positive Spiral Computed Tomography Lung Carcinoma Screen." Cancer. Published online Nov. 4, 2004.

Abstract online: www3.interscience.wiley.com