When most people hear "lung cancer," they immediately picture a heavy smoker. While smoking remains the leading cause of the disease, a alarming reality is emerging: lung cancer cases among non-smokers, particularly women, are rising rapidly. Lung cancer does not discriminate, and it isn't limited to tobacco users. Why Are Non-Smokers Developing Lung Cancer? Genetics: A family history of lung cancer can make an individual more susceptible to the disease.