Core needle biopsy removes a small sample of tissues from a breast lump by inserting a special needle into an area of concern. The core needle is thicker than the needle used for FNA, it is about 1–2 mm in diameter. Like FNA, core needle biopsy is also done under local anaesthetic and ultrasound scan guidance. A small cut of around 1–2 mm is made on the skin and the core needle is gently inserted into the breast lump to take tissue samples. When a sample is taken, there is a clicking noise, and the woman may feel pressure on her breast. The doctor may repeat the sampling step a few times in order to make sure adequate tissues are taken. The procedure takes around 20–30 minutes. When this is finished, the biopsied area is pressed on firmly with an ice pack for a few minutes to reduce bruising and bleeding, and then covered with a dressing. The small skin cut heals by itself over a few days and does not require any stitches.
In addition to cells, the core needle biopsy can also obtain tissue samples for examination. The core needle biopsy therefore has a higher accuracy when it comes to diagnosing a breast lump. Thus, if either ultrasound scan or mammogram shows features suspicious of cancer, the doctor will recommend a core needle biopsy so as to get a more accurate assessment and diagnosis of the nature of the breast lump.