To determine whether a growth is cancerous, a biopsy (tissue sample) is extracted for further testing. Biopsies are often used in diagnosing cancer when a mass is found during a screening exam.

Biopsy procedures are guided by imaging technology, such as MRI, ultrasound or other methods, and can be performed by:

• Needle – Fine needle and core needle biopsies are used to extract cells or a small core of tissue.
• Stereotactic – Computer and imaging technology are used to guide a needle to a precise spot where a tissue sample can be collected.
• Open or surgical – A sample of the growth, or entire growth, is taken by making a small incision in the skin.