What Does Degenerative Joint Disease Mean>?

Hi doc! I'm 43 yrs old lady, 5'2" tall and was diagnosed to have breast cancer in Oct, 2009. I was operated the following month and had undergone chemotheraphy. I had my bone scan last January 2011 and the result is... DEGENERATIVE JOINT DISEASE. What does this mean? Is it ok to have my bonescan again after 6 months? Thanks doc!