I was diagnoised with invasive ductual carcinoma grade III and had a lumpectomy to remove it. The margins came back clean from the surgery. I am having chemo treatments and herceptin for 1 year. Shouldn't the lumpectomy and the chemo take care of the cancer? Why do I have to have radiation also? I have read a lot about radiation causing cancer. It seems like this is just overkill.