Inhaled Corticosteroids May Lower Lung Cancer Risk in COPD

SEATTLE, April 2 -- High doses of inhaled corticosteroids may reduce the risk of lung cancer in men with chronic obstructive pulmonary disease (COPD), according to researchers here.

In a cohort study of 517 mostly male veterans who used inhaled corticosteroids, a dose of more than 1,200 mcg a day led to a 61% reduction in the risk of lung cancer compared with a cohort of non-users, found David Au, M.D., of the Veterans Administration Puget Sound Health Care System here, and colleagues.

In contrast, men with COPD who used less than 1,200 mcg a day had a slightly elevated risk of developing lung cancer, although the trend did not reach statistical significance, Dr. Au and colleagues reported in the first April issue of the American Journal of Respiratory and Critical Care Medicine.

Because tobacco has an inflammatory effect and inhaled corticosteroids have an anti-inflammatory effect, the researchers hypothesized that the medications might have a chemopreventive effect on lung cancer, he said.

Among 10,474 Veterans Affairs patients with COPD, Dr. Au and colleagues reported that they found 517 who were considered regular users of corticosteroids-that is, they took their medication at least 80% of the time.

The researchers stratified the steroid users into high- and low-dose groups -- at least 1,200 mcg a day or less than that -- and compared the occurrence rate of lung cancer among them and the remaining 9,957 non-users over an average follow-up of 3.8 years.

In a multivariate analysis, adjusting for such factors as age, smoking status, smoking intensity, and bronchodilator use, they found:

• The steroid non-users (the reference group) developed 402 cases of lung cancer.
• The 298 patients taking low doses of inhaled corticosteroids developed 16 cases of lung cancer, for a hazard ratio of 1.13 (with a 95% confidence interval from 0.67 to 1.90).
• The 219 patients on high-dose inhaled corticosteroids developed five cases of lung cancer, for a hazard ratio of 0.39 (with a 95% confidence interval from 0.16 to 0.96).

The study can't say anything about cause and effect and is relatively small, the researchers acknowledged, but if the finding is confirmed, it "has potentially important implications for lung cancer pathogenesis and chemoprevention."

Indeed, if the risk reduction is confirmed, it would be "a clinically significant achievement particularly in light of the continued lung cancer epidemic," said York Miller, M.D., and Robert Keith, M.D., both of the University of Colorado at Denver, in an accompanying editorial.

They said the data presented by Dr. Au and colleagues are "certainly not definitive" but are enough to warrant further investigation in prospective controlled trials.