We found that 16.2% of the study population (106 out of 654 patients) could be screened and diagnosed with lung cancer, per the USPSTF’s recommendation that former smokers with a smoking history of 20–29 pack years who quit within the last 15 years are at a higher risk of oxidative stress, programmed cell death, and GSTM1 deficiency or deletion. This evidence concerns the gene GSTM1 and lung cancer.