Needle biopsies of a lump or bump to diagnose breast cancer causes it to spread. Needle biopsies are used to take a small tissue or fluid sample from a suspicious lump or bump in your breast for cancer testing. A study on needle biopsies showed the procedure does not cause cancer to spread. Surgery to remove breast cancer will not cause it to spread either. The greatest survival rates are achieved by removing as much of the tumor as soon as possible. Sometimes during surgery it is discovered that the cancer has spread further than expected. This allows your doctor to treat you more effectively.