Most breast lumps found in women need to be looked at under the microscope to make sure they're not cancer. But new research says too many women are getting unnecessarily aggressive open biopsies, which produce a scar, when most of them could get enough tissue for sampling with a simple needle stick.

About 1.6 million breast biopsies are done every year in the United States, with about 200,000 of those resulting in a diagnosis of invasive cancer, which requires more treatment. That means that about seven in eight women who undergo biopsy receive the good news of no cancer (or the pre-invasive diagnosis of ductal carcinoma in situ).