Sputum Test Could Improve Lung Cancer Screening

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http://www.reuters.com/newsArticle.jhtm ... ID=4016505

Sputum Test Could Improve Lung Cancer Screening

Thu December 18, 2003 12:09 PM ET

NEW YORK (Reuters Health) - A CT scan of the chest can reliably pick up early lung cancer. The problem is that it also spots a lot of non-cancerous nodules - that is, the false-positive rate is high - and it sometimes misses small cancers in the central part of the chest.

Now, Canadian researchers have shown that performing a sputum analysis could help decide when to order a CT scan, and improve it's accuracy.

Dr. Annette McWilliams, from the British Columbia Cancer Agency in Vancouver, and colleagues decided to look at the usefulness of an automated system to screen for abnormal cells in sputum samples, as a means of guiding CT screening for 561 current or former smokers.

All of the subjects were at least 50 years of age and had a history of smoking the equivalent of a pack a day for 30 years or more.

Of the study group, 423 subjects had sputum samples that showed abnormal cells, the researchers report in the American Journal of Respiratory and Critical Care Medicine. Non-cancerous lung nodules were a very common finding on CT, identified in 46 percent of subjects.

Fourteen cancers were detected and all but one occurred in subjects with abnormal sputum cells, the researchers found. Of the 13 cancers detected in subjects with abnormal sputum cells, 9 were detected by CT.

If only CT had been performed, 29 percent of the cancers would have been missed.

Performing sputum analysis before CT improved the detection rate of lung cancer from 1.8 percent to 3.1 percent, the researchers note.

This strategy "has the additional potential of reducing the number of initial CT scans by at least 25 percent with further savings in follow-up investigations and treatment," McWilliams' team adds.

SOURCE: American Journal of Respiratory and Critical Care Medicine, November 15, 2003.