Lumps or abnormalities in the breast are often found with physical examination, mammography, or other imaging studies. But it’s not always possible to tell from these imaging tests whether a growth is benign or cancerous.
A breast biopsy is performed to remove some cells, either surgically or through a less invasive procedure involving a hollow needle, from a suspicious area in the breast and examine them under a microscope to determine a diagnosis. Image-guided needle biopsy is not designed to remove the entire lesion, but most of a very small lesion may be removed in the process of biopsy.
Image-guided biopsy is performed by taking samples of an abnormality under some form of guidance such as ultrasound, MRI or mammographic guidance.
In ultrasound-guided breast biopsy, ultrasound imaging is used to help guide the radiologist’s instruments to the site of the abnormal growth.
What Should I Expect From the Procedure?
You will lie on your back, and the breast skin will be cleaned and draped to keep the area sterile. A small amount of sterile gel is put on the skin to allow the sound waves to travel back and forth from the transducer. You will be awake during your biopsy, and should have little or no discomfort. Most women report little or no pain, and no scarring on the breast.
One of four instruments will be used:
- A fine needle attached to a syringe, smaller than needles typically used to draw blood.
- A core needle, also called an automatic, spring-loaded needle, which consists of an inner needle connected to a trough, or shallow receptacle, covered by a sheath and attached to a spring-loaded mechanism.
- A vacuum-assisted device (VAD), an instrument that uses pressure to pull tissue into the needle.
- A thin guide wire, which is used for a surgical biopsy.
Using an ultrasound scanner to visualize breast mass, distortion or abnormal tissue change, the radiologist numbs the area with lidocaine, inserts a biopsy needle through the skin, advances it into the targeted finding, and removes tissue samples. If a surgical biopsy is being performed, ultrasound may be used to guide a wire directly into the targeted finding to help the surgeon locate the area for excision or lumpectomy. With continuous ultrasound imaging, the physician is able to view the biopsy needle or wire as it advances to the location in real-time.
A small marker may be placed at the biopsy site so that it can be located in the future if necessary. Once the biopsy is complete, pressure will be applied to stop any bleeding, and the opening in the skin covered with a dressing. No sutures are needed. A mammogram may be performed to confirm that the marker is in the proper position. This procedure is usually completed within an hour.
If you experience swelling and bruising following your biopsy, you may be instructed to take an over-the-counter pain reliever and to use a cold pack. Temporary bruising is normal.
You should contact your physician if you experience excessive swelling, bleeding, drainage, redness, or heat in the breast.
You should avoid strenuous activity for 24 hours after the biopsy. After that period of time, you will usually be able to resume normal activities.
Who Interprets the Results and How do I Get Them?
A pathologist examines the specimen and makes a final diagnosis. Depending on the facility, the radiologist or your referring physician will share the results with you.
Follow-up examinations may be necessary, and your doctor will explain the exact reason why another exam is requested.
What are the Benefits Versus Risks?
- The procedure is less invasive than surgical biopsy, leaves little or no scarring and can be performed in less than an hour.
- Ultrasound imaging uses no ionizing radiation.
- Ultrasound-guided breast biopsy reliably provides tissue samples that can show whether a breast lump is benign or malignant.
- Compared with stereotactic breast biopsy, the ultrasound method is faster and avoids the need for ionizing radiation exposure.
- With ultrasound, it’s possible to follow the motion of the biopsy needle as it moves through the breast tissue.
- Ultrasound-guided breast biopsy is able to evaluate lumps under the arm or near the chest wall, which are hard to reach with stereotactic biopsy.
- Ultrasound-guided biopsy is less expensive than other biopsy methods, such as open surgical biopsy or stereotactic biopsy.
- Recovery time is brief and patients can soon resume their usual activities.
- There is a risk of bleeding and forming a hematoma, or a collection of blood at the biopsy site. The risk is less than one percent of patients.
- Some patients have significant discomfort, which can be controlled by non-prescription pain medication.
- Any procedure where the skin is penetrated carries a risk of infection. The chance of infection requiring antibiotic treatment appears to be less than one in 1,000.
- Depending on the type of biopsy being performed or the design of the biopsy machine, a biopsy of tissue located deep within the breast carries a slight risk that the needle will pass through the chest wall, allowing air around the lung that could collapse a lung. This is a rare occurrence.
What are the Limitations of Ultrasound-Guided Breast Biopsy?
Breast biopsy procedures rarely miss a lesion, or underestimate the extent of disease present. If the diagnosis remains uncertain after a technically successful procedure, surgical biopsy is usually be necessary.
The ultrasound-guided biopsy method cannot be used unless the lesion can be seen on an ultrasound exam. Clustered calcifications are not shown as clearly with ultrasound as with x-rays.
Very small lesions may be difficult to target accurately by ultrasound-guided core biopsy.