Smoking as a Secondary Risk Factor

Whether a patient has a cancer that is smoking-related or nonsmoking related, he or she is at increased risk of developing a second cancer at the same or another site, if smoking is not stopped. The risk of developing a second cancer may persist for up to 20 years, even if the original cancer has been successfully treated.

Patients with oral and pharyngeal cancers who smoke also have a high rate of second primary cancers. The risk decreases significantly, however, after 5 years of not smoking.