If these blocks become disorganized, cancer may develop. For example, if a woman has close family members who have had breast cancer, she is more likely to get breast cancer. Some cancers are caused by outside factors. For example, anyone who smokes is more likely to get lung, throat or mouth cancer. A tumor is a mass of abnormal cells.
Tumors are either benign or malignant.
Benign tumors usually grow very slowly and generally do not spread. Doctors can remove most of them. This is called localized disease. As cancers continue to grow, they are more likely to spread or metastasize into the lymph nodes. This is called regional disease.