Home > General Medicine > Lung Cancer Top Killer Get the Flash Player to see this player. Rate: (Click the stars to rate) Published on Aug 30, 2010 by Cleveland Clinic, Views: 2449 If you're a smoker who's still looking for a New Year's Resolution, this might help you make up your mind. The National Cancer Institute says lung cancer remains the number one cancer killer in the United States, and smoking caused nearly 90% of lung cancer deaths all year.