December 20, 2005

Chest x-rays detect early lung cancer

By Megan Rauscher

NEW YORK (Reuters Health) - Screening chest x-ray detects a
substantial number of lung cancers at an early potentially
curable stage, according to initial findings from the largest
US study of the efficacy of screening for lung cancer in men
and women.

According to the initial chest x-rays of 77,465 people in
the screening arm of the trial, 5,991 -- nearly 9 percent --
had results that were deemed "suspicious for lung cancer."

Upon further testing, 126 individuals were diagnosed with
lung cancer and, importantly, say the investigators, 44 percent
of the tumors were early localized stage I cancers.

"This is a tantalizing first step, raising the possibility
of real benefit," Dr. Martin M. Oken, of the Hubert H. Humphrey
Cancer Center, Robbinsdale, Minnesota told Reuters Health.

"Screening," he pointed out, "is predicated on the
assumption that it can lead to discovery of dangerous cancers
at an earlier, more localized stage when it is more likely to
be curable. In the current study, nearly 50 percent of
screen-detected lung cancer is localized."

Historically, in unscreened populations, only 15 percent to
20 percent of lung cancers are diagnosed while localized.

Worldwide, one million people die from lung cancer each
year. When lung cancer first develops, there may be no symptoms
at all. When a patient starts to experience symptoms, such as a
cough that doesn't go away, the cancer is often advanced and
treatment is rarely effective.

In the current study, high rates of lung cancers were found
in current smokers and in former smokers (6.3 and 4.9 per 1000
screens). Among never smokers, the lung cancer detection rate
was 0.4 per 1000 screens. This group accounted for 11 percent
of the cancer identified.

The final analysis of the study, Oken said, will compare
the findings in these 77,465 screened individuals, which are
reported in today's Journal of the National Cancer Institute,
with a like number of unscreened subjects to determine whether
screening can reduce death from lung cancer.

"As little as a 20 percent mortality reduction associated
with screening," he concluded, "could save 32,000 lives
annually in the US alone."

SOURCE: Journal of the National Cancer Institute, December
21, 2005.