In a large, nested cohort study, use of inhaled corticosteroids at doses greater than 1,200 mcg/d was associated with a 61% reduction in the risk of developing lung cancer in patients with chronic obstructive pulmonary disease.
In explaining the potential mechanism underlying ICSs' chemo-preventive properties, the authors stated: "Previous studies have demonstrated that ICS[s] reduce local and systemic inflammation among patients with COPD, and animal models have demonstrated that glucocorticoids inhibit growth of lung cancer cells."
Patients (n=10,474) were selected from the Ambulatory Care Quality Improvement Project (ACQUIP) study, a multicenter randomized trial involving veterans that assessed how patients' self-reported health affected their health status and level of satisfaction of care. To be included in the cohort study, patients must have been diagnosed with COPD, must have self-reported chronic lung disease, or must have had a prescription for a bronchodilator (beta2-agonist or anticholinergic) in the 12 months before their enrollment date. Exposure to ICS was defined as ≥80% adherence to medication during the 180 days prior to the index date. Patients with lung cancer were excluded from the study. Median follow-up was 3.8 years.
The authors stated that the study could have important implications for lung cancer pathogenesis and chemoprevention if further research confirms these results. "One advantage of this study is the information on compliance; a weakness is the relatively small number of subjects and incident cases of lung cancer in the group that apparently accrued benefit," they stated.
In an accompanying editorial, Yor E. Miller, MD, et al agreed with the authors' assessment and stated: "Although the data at present are certainly not definitive, inhaled corticosteroids deserve further consideration for lung cancer chemoprevention. Adequately powered, prospective, controlled trials with prolonged follow-up to capture effects on a carcinogenic process that progresses over years will ultimately be needed to determine efficacy."
Lung cancer is the most common cause of cancer-related death in the United States and is also the most common cause of death among patients with COPD. Guidelines for the treatment of COPD recommend the addition of an ICS to bronchodilator treatment in symptomatic COPD patients with severe or very severe COPD (stage III or IV) and repeated exacerbations (>3 exacerbations over a 3-year period).
Parimon T, Chien JW, Bryson CL, McDonell MB, Udris EM, Au DH. Inhaled corticosteroids and risk of lung cancer among patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2007;175:712–719.
Miller YE, Keith RL. Inhaled corticosteroids and lung cancer chemoprevention. Am J Respir Crit Care Med. 2007;175:636–637.
Global Initiative for Chronic Obstructive Lung Disease (GOLD). Executive summary: Global strategy for the diagnosis, management, and prevention of COPD. http:// http://www.goldcopd.org/guidelineitem.asp?l1=2&l2=1&intid=996. Accessed May 7, 2007.