Abstract
A new drug for chronic obstructive pulmonary disease has been recently added as a treatment for certain patients. However, new evidences indicate that there might be a connection with lung cancer. It is known that smoking is a major factor that induces chronic pulmonary disease and smoking is associated with lung cancer. The level of connection between phosphodiesterase (PDE)-4 inhibitors and lung cancer will be discussed based on current studies. A comment will be made whether lung cancer is induced to patients receiving phosphodiesterase (PDE)-4 inhibitors from the drug or former smoking habit.