The majority of abnormal findings prove to be false positives, study finds
WEDNESDAY, Dec. 21 (HealthDay News) -- While chest X-rays can detect early lung cancer, they can also produce many false positive results, a new study finds.
Researchers at the U.S. National Cancer Institute analyzed data from the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Of the more than 67,000 people who received a baseline chest X-ray when they entered the trial, nearly 6,000 -- close to 9 percent -- had abnormal results that required follow-up.
After further tests, just 126 (2.1 percent) of those with abnormal chest X-rays were diagnosed with lung cancer within 12 months of their initial chest X-ray. Of the lung cancers that were detected, 44 percent were stage I. Patients with stage I lung cancer are considered good candidates for surgery.
"The positive predictive value (of chest X-rays) was low. That means that there were a lot of false positives on the initial X-rays. If you get a positive result from a chest X-ray, the message is 'don't panic,'" Dr. Christine Berg, the NCI investigator leading the trial, said in a prepared statement.
She noted that tissue variations and other benign factors can appear as tumors on X-rays.
"The rate of early cancer detection was better than what we see in the general community. But it remains to be seen if that translates into a mortality benefit. It is too early to make any recommendations regarding chest X-rays as a lung cancer screening tool in the general population," Berg said.
The findings are reported in the Dec. 21 issue of the Journal of the National Cancer Institute.
SOURCE: U.S. National Cancer Institute, news release, Dec. 20, 2005
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