In the study, only 1% of people who’d never smoked developed lung cancer by age 80. The study found that the risk of developing lung cancer increases to 14% if you smoke cigarettes.If you smoke one to five cigarettes per day, your risk is around 7.7%, and if you smoke more than 35 cigarettes per day, you’ll have a 26.4% chance of developing lung cancer by age 80.Bear in mind that you don’t need to smoke in order to develop smoking-related cancers. Secondhand smoke also increases your risk of developing lung cancer.