(HealthDay News) — Extended follow-up of the National Lung Screening Trial (NLST) showed that the number needed to screen to prevent one lung cancer death among patients at high risk for lung cancer is 303, similar to the original estimate, according to a study published online June 28 in the Journal of Thoracic Oncology.

Denise R. Aberle, M.D., from the University of California Los Angeles, and colleagues report on an extended follow-up of NLST patients. They followed patients by linkage to state cancer registries and the National Death Index.

Patients were followed for a median of 11.3 and 12.3 years for incidence and mortality, respectively. The researchers found that 1,701 and 1,681 lung cancers were diagnosed in the low-dose computed tomography (LDCT) and chest radiograph (CXR) arms, respectively (rate ratio, 1.01; 95 percent confidence interval, 0.95 to 1.09). There were 1,147 and 1,236 observed lung cancer deaths in the LDCT and CXR arms, respectively (rate ratio, 0.92; 95 percent confidence interval, 0.85 to 1.00). The number dying of lung cancer differed by 3.3 per 1,000 across the arms, translating into a number needed to screen of 303. The rate ratio was 0.89 (95 percent confidence interval, 0.80 to 0.997) for dilution-adjusted lung cancer mortality. For overall mortality, there were 5,253 and 5,366 deaths in the LDCT and CXR arms, respectively, for a difference of 4.2 per 1,000 (95 percent confidence interval, −2.6 to 10.9).

“The stability of this difference over time indicates that LDCT screening did not just delay lung cancer death by a few years, but prevented it, or at least delayed it for more than a decade,” the authors write.

Several authors disclosed financial ties to the pharmaceutical and medical device industries.

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