The development of asthma was found to be associated with an increased risk for subsequent cancer, according to study results published in The Journal of Allergy and Clinical Immunology.
In this study, 2 independent, population-based, longitudinal Korean cohorts were examined: the National Health Insurance Service-National Sample Cohort (NHIS-NSC) and the Ansan-Ansung cohort. The large, population-based, nationwide NHIS-NSC cohort comprised an unmatched cohort of 475,197 participants and a propensity, score-matched cohort of 75,307 participants (claims-based data from 2003 to 2015). The population-based, prospective Ansan-Ansung cohort included a total of 5440 participants (interview-based data from 2001 to 2014).
In the NHIS-NSC matched cohort, there were a total of 572,740 person-years of follow-up, 6885 individuals with a new diagnosis of asthma, and 68,422 persons without a diagnosis of asthma. Overall, adults diagnosed with vs without asthma had a 75% greater risk of developing incident cancer (fully adjusted hazard ratio [aHR], 1.75; 95% CI, 1.58-1.94; P <.001), with this relationship persisting following competing risk analysis for mortality (aHR, 1.62; 95% CI, 1.47-1.80). The excess risk for incident cancer was highest in the first 2 years after a diagnosis of asthma, and remained elevated during the follow-up period.
Asthma was associated with an increased risk for bladder cancer (fully aHR, 5.43; 95% CI, 3.24-9.09), lung cancer (aHR, 3.62; 95% CI, 2.78-3.71), blood cancer (aHR, 2.06; 95% CI, 1.04-4.06), oral cavity and esophageal cancer (aHR, 2.02; 95% CI, 1.09-3.72), sex-specific cancer (aHR, 1.94; 95% CI, 1.59-2.37), pancreatic cancer (aHR, 1.93; 95% CI, 1.16-3.20), stomach cancer (aHR, 1.46; 95% CI, 1.01-2.10), liver cancer (aHR, 1.44; 95% CI, 1.04-1.99), and colorectal cancer (aHR, 1.37; 95% CI, 1.01-1.85).
Patients diagnosed with nonatopic asthma had a greater risk for the development of overall cancer compared with those with atopic asthma (aHR, 3.35; 95% CI, 2.88-3.89 vs aHR, 1.36; 95% CI, 1.20 to 1.53, respectively). A high cumulative dose of inhaled corticosteroids among patients with asthma was associated with a 56% decreased risk for lung cancer but had no effect on the risk for overall cancer. Results from the NHIS-NSC unmatched cohort and the Ansan-Ansung cohort were similar to the primary results from the NHIS-NSC matched cohort.
“Our results thus provide an improved understanding of the relationship between the pathogenesis of asthma and the pathogenesis of cancer, and suggest that clinicians should be aware of the greater risk of incident cancer in patients with asthma,” concluded the study authors.
Woo A, Lee SW, Koh HY, Kim MA, Han MY, Yon DK. Incidence of cancer after asthma development: two independent population-based cohort studies [published online May 14, 2020]. J Allergy Clin Immunol. doi:10.1016/j.jaci.2020.04.041