Analysis Buttresses Idea That Inhaled Corticosteroids in COPD Guard Against Lung Cancer

Inhaled corticosteroids (ICs) may provide some protection against lung cancer in patients with chronic obstructive pulmonary disease (COPD), according to a recent meta-analysis published in Translational Lung Cancer Research.

Previous evidence has shown that the risk of developing lung cancer is associated with COPD severity and inflammation. Additionally, some studies have found that chronic inflammation involved in the onset of lung cancer was partially independent of smoking status.

Cohort studies have suggested that ICs could delay or prevent lung cancer incidence. However, lung cancer prevalence is still higher among patients with COPD who use ICs than the general population, suggesting that more research on this phenomenon is needed.

The researchers searched 4 databases to find longitudinal epidemiological studies published between 1966 and February 2020. To be included in the analysis, studies had to be population-based cohort studies, report the risk of lung cancer in patients with COPD taking ICs, and allow for analysis of crude or adjusted hazard ratios (HRs).

Out of 816 potential studies, 9 were included in the analysis after exclusion, representing 181,859 patients with COPD. The patients were followed for a total of 1,109,339.9 person-years, with a mean follow-up period of 6.1 years. The participants’ mean age was 68.1 years for those who used ICs and 68.0 years for those who did not.

The studies were from a variety of countries, including 1 from the United Kingdom, 2 from China, 1 from the Republic of Korea, 1 from Sweden, 2 from Norway, and 2 from Canada.

A pooled analysis found that ICs had a protective effect against lung cancer in patients with COPD (HR, 0.73; 95% CI, 0.62-0.86; P < .001) and heterogeneity among the studies was high (I2 = 64.4%, P_{heterogeneity} = .004).

When stratifying by age, patients aged 70 or older had an HR for lung cancer of 0.80 (95% CI, 0.64-0.99, P = .043; I2 = 71.7%; P_{heterogeneity} = .114). Patients younger than 70 had an HR of 0.73 95% CI, 0.54-0.99; P = .040; I2 = 49.6%; P_{heterogeneity} = .137).

Stratification for different regions demonstrated HRs for lung cancer of 0.62 (95% CI, 0.45-0.86; P = .004; I2 = 49.5%; P_{heterogeneity} = .114) for European patients and 0.77 (95% CI, 0.60-0.97; P = .028; I2 = 32.5%; P_{heterogeneity} = .228) for Asian patients.

The researchers suggested that the ICs properties that prevent epithelial-mesenchymal transition in airways of patients with COPD could be a possible explanation for the protective effects observed in the analysis.

Additionally, a dose-response relationship between ICs exposure and risk of lung cancer development was found in 2 studies, showing that higher doses of ICs may be associated with a lower risk of lung cancer.

The authors said they believed their meta-analysis was the first to assess the possible relationship between ICs and the risk of lung cancer. “Such an association can provide guidance for clinicians in the prevention of lung cancer among patients with COPD,” wrote the researchers.

Some limitations were detected, including that a dose-response relationship could not be definitively determined, there was a lack of information on potential lung cancer risk factors, and that a publication bias was unavoidable.

Reference

Ge F, Feng Y, Huo Z, et al. Inhaled corticosteroids and risk of lung cancer among chronic obstructive pulmonary disease patients: A comprehensive analysis of nine prospective cohorts. Transl Lung Cancer Res. 2021;10(3):1266-1276. doi: 10.21037/tlcr-20-1126