A reduction in lung cancer mortality was independently associated with the use of aspirin, metformin, or statin use alone or together, according to results of a population-based cohort study published in the Journal of Thoracic Oncology.1

Previous studies have shown mixed results on whether aspirin, metformin, or statins has a protective effect against cancers. The purpose of this study was to evaluate this question for lung cancer in a large cohort of patients.

The nationwide population study included 732,199 patients who underwent a national health check-up between 2002 and 2003. The patients were followed for 9 years beginning in 2004. Lung cancer cases were identified using the ICD-10 code and mortality was determined using the Korean National Death Registry.

Exposure to medication was measured as cumulative duration of use or cumulative defined daily dose (cDDD) per 2 years. Medication exposure was used as a time-dependent variable in Cox analysis. Several models were used to adjust for covariates such as age, sex, income, body mass index, smoking status, and alcohol use.


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At baseline, 9% of patients were ever-users of aspirin and 5.1% were ever-users of statins. Type 2 diabetes was present in 6.3% of patients (46,205), of whom, 55.8% were ever-users of metformin.

During follow-up, 5990 lung cancers were diagnosed, and 5938 patients died from the disease.

There was no association between ever-use of aspirin and incidence of lung cancer or lung cancer–related mortality. Cumulative use of aspirin, however, was associated with lung cancer–related mortality (adjusted hazard ratio [aHR], 0.87; 95%CI, 0.78-0.97; P =.073).

Ever-use and cumulative use of statins was not associated with lung cancer incidence. High levels of cumulative statin use was associated with a decrease in lung cancer–related mortality (aHR, 0.77; 95% CI, 0.59-0.99; P =.004).

Among patients with type 2 diabetes, ever-use of metformin was significantly associated with a decreased incidence of lung cancer compared with patients without diabetes (aHR, 0.89; 95% CI, 0.81-0.98). There was also an association between cumulative metformin use and decreased lung cancer incidence (aHR, 0.44; 95% CI, 0.29-0.66), but not mortality (aHR, 0.76; 95% CI, 0.54-1.09).

There was a stronger association between metformin and lung cancer mortality among nonsmokers and women compared with the entire cohort.

Combined ever-use vs never-users of aspirin, metformin, and statins was also associated with reduced lung cancer incidence (aHR, 0.83; 95% CI, 0.69-0.99) and mortality (aHR, 0.83; 95% CI, 0.70-0.99). A longer duration of combined use was associated with progressively lower risk of developing lung cancer or lung cancer–related mortality.

The authors concluded that “individual uses of aspirin, metformin, and statins have independent protective associations with lung cancer mortality, and metformin showed inverse association with the incidence of lung cancer.” They added that additional research is needed to develop clinically relevant anticancer strategies based on these findings.

Reference

Kang J, Jeong S-M, Shin DW, et al. Associations of aspirin, statins, and metformin with lung cancer risk and related mortality: time-dependent analysis of population-based nationally representative data. J Thorac Oncol. Published online September 17, 2020.