How bad is diagnosis of invasive ductal carcinoma high grade?

Depends: Not all breast cancers are the same and many other factors help to predict better or poorer outcomes such as tumor grade, # of positive lymph nodes, estrogen receptor status, her2neu status, etc. A score called oncotype DX based on genetic profiling of the cancer helps define prognosis also and tailor decisions as to the best and most beneficial treatment to use.