A biopsy is surgery to remove a sample of tissue. A pathologist examines the biopsied tissue under a microscope to see if any cancer is present.

The diagnosis of breast cancer depends upon examination of tissue or cells removed by biopsy. A biopsy is the only way to know for sure if a breast change is benign or malignant.

There are a number of methods, depending upon the size and location of the lump or suspicious area, and the general health of the patient. These include:

Aspiration: The use of a...