Overview of Stereotactic and Needle Breast Biopsy
Breast cancer is the second leading cause of cancer-related deaths in women across the world. In 2018, over 234,000 cases were identified in the U.S., and globally, there were 2.2 million diagnoses. A lot of these cancers do not initially show any symptoms and cannot be felt, but are discovered through mammogram screenings or other imaging techniques. Recently, there’s been an increase in the occurrence of breast cancer in women under the age of 50, and these instances often present with more unfavorable conditions.
To decide on the right course of treatment, it’s crucial to get a tissue diagnosis of any breast-related abnormalities. In the past, the only way to achieve this was through a procedure known as an excisional biopsy, used mainly for lumps that could be felt. For identifying issues only visible on mammograms, it was a significant problem, typically involving marking the area for biopsy with a wire, dye, or carbon.
However, in the late 1980s, there was a momentous shift in the approach for diagnosing and treating women with breast abnormalities detected via mammography. Dr. Steve H Parker introduced something known as stereotactic core biopsy. This technique and many advancements that followed — like the integration of the biopsy needle into the mammogram system and the enhanced compatibility of the biopsy device with MRI – have greatly improved cancer detection. These developments have made it possible to perform millions of breast biopsies every year with high precision and low complication rates. As a result, many patients with non-palpable breast cancer now have an effective, less invasive, and cost-friendly alternative to traditional surgical biopsies.
Anatomy and Physiology of Stereotactic and Needle Breast Biopsy
The development of breasts starts during embryonic development and their growth slows down until puberty. At puberty, parts of the breasts like the breast mound and the area surrounding the nipple, called the areola, start to grow due to the effect of sex hormones. The overlying skin of the breast consists of different layers, including dermal appendages like sweat glands, hair follicles, small blood vessels, and nerve endings. Underneath lies a layer containing larger blood vessels, nerves, and fat tissue, which is separated from the nearby body structures by a thin layer called the fascial layer.
The shape of the breasts is determined by the suspensory ligaments anchoring the fascial layer to the skin, along with the subcutaneous fat and glandular tissue. The blood supply to the breasts comes from the internal mammary arteries, intercostal perforators, and branches of the axillary artery. The breasts also contain a system of veins, and the lymphatic drainage is primarily directed towards the same side armpit (ipsilateral axilla).
The breast tissue, also known as parenchyma, is made up of sac-like dilations known as ductules or acini. These are lined with specialized cells responsible for milk production in response to hormonal signals. A group of these ductules is called a lobule. These lobules connect through a duct within each lobule, which further communicates with another duct known as the terminal ductal lobular unit. This unit is crucial in breast imaging and also happens to be the primary origin of breast cancer. Each female breast has about 12 to 20 lobes, each with a main draining duct that connects to the nipple-area and forms a storage area for milk, called the lactiferous sinus.
The axillary region, the area under your arm and between the chest’s side, the upper arm’s inside and the shoulder blade, contains lymph nodes. These are classified into three levels according to their positions relative to a muscle in the chest, called the pectoralis minor muscle.
Why do People Need Stereotactic and Needle Breast Biopsy
The Breast Imaging and Reporting System (BI-RADS) is a system created by the American College of Radiology to classify irregularities that might be found in breast tissue during a mammogram, which is a special type of x-ray used to detect abnormalities in the breast. This system gives a numerical score, from 1 to 6, to each irregularity. The higher the score, the more likely it is that the irregularity could be breast cancer.
During a mammogram, if a complex cyst (a sac containing fluid that doesn’t look like ordinary breast tissue), a solid lump, or something else abnormal is found in your breast, a biopsy might be suggested. A biopsy is a procedure where a small amount of tissue is removed from the body for testing.
BI-RADS 0 means that the results of the mammogram weren’t clear, and more tests are needed. These could include an ultrasound test, which uses sound waves to create images of the inside of the breast. Rarely, an MRI, which uses magnetic fields and radio waves to create images of the body, might be needed. BI-RADS 4 scores are given to areas that could contain cancer, so if you receive a BI-RADS 4 result on your mammogram, a biopsy is usually recommended.
Occasionally, if a suspicious area seen on a mammogram can’t be seen on an ultrasound, further evaluation may be necessary. This could include a type of biopsy that uses mammography to locate the area in need of testing, or an MRI-guided biopsy for areas that cannot be clearly seen on mammogram. When a biopsy result shows no presence of cancer but the mammogram or other imaging shows suspicious signs, additional tests or biopsies are usually recommended.
Our techniques and ability to interpret these tests are always improving. For example, a newer technique called radiomics, analyzes the shape and textural characteristics of breast lesions found in medical images. This tool can be especially helpful in interpreting BI-RADS 4 and 5 results, which are seen as more likely to be cancer. The results of radiomics are often combined with the BI-RADS number to provide a more comprehensive understanding of breast abnormalities.
When a Person Should Avoid Stereotactic and Needle Breast Biopsy
A core biopsy, which is a procedure to remove a small piece of tissue for testing, should not be done for breast lumps that are less than 5 mm in their longest length. This is because the biopsy could unintentionally take out the whole lump. There are also other situations where a core biopsy may not be safe. These include if the skin over the lump is infected or if the person has a high risk of bleeding.
There are also some specific situations where a stereotactic guided biopsy, which uses mammogram images to guide the biopsy needle, should not be done. These include if the person is pregnant, if their breast is too large to be properly compressed for the mammogram, or if they cannot be positioned correctly for the test. The same conditions apply for a magnetic resonance-guided biopsy, which uses MRI images to guide the needle. In addition to these, having implants or other foreign materials in the body can also make the MRI-guided biopsy risky.
Equipment used for Stereotactic and Needle Breast Biopsy
The American College of Radiology (ACR) and the US government set rules and quality standards for breast imaging, like ultrasound, mammography, and magnetic resonance, or MRI. These standards help ensure that the images produced are clear and accurate. Certified medical physicists or associates check these standards to make sure they are being met.
Hand-held ultrasound machines use a method called brightness mode to create images. This involves sending sound waves into a small layer of tissue, measuring the sound waves that bounce back, and turning these measurements into an image on the screen. Various factors like the physical properties of the probe, technical factors and the makeup of the tissue being scanned can affect the clarity of the image.
Mammographic-guided stereotactic biopsy machines develop images using a type of energy called ionizing radiation. Some of these machines are specifically for biopsies, while others are attached to standard mammography machines. The way the equipment for the biopsy is set up, how the patient is positioned, and the software used can vary between machines and manufacturers. Some new machines can perform a special type of 3-D mammogram called tomosynthesis for the biopsy.
MRIs make images using a combination of radio waves and magnetic field strength. For this, the patient is placed inside a supercooled magnet that can change magnetic fields. The changes caused by coils and radio waves are measured and turned into an image. Different places and different scanners may have slightly different ways of taking an MRI guided biopsy. While MRI has the benefit of not using ionizing radiation, there can be risk related to the magnetic field, especially if the patient has certain implanted devices like pacemakers or neurostimulators. Other techniques using nuclear medicine to guide biopsies, like gamma imaging and positron emission mammography, are not commonly used.
Who is needed to perform Stereotactic and Needle Breast Biopsy?
The Mammography Quality Standards Act (MQSA) is a legislation that sets standards for breast health check-ups, like breast biopsies. Biopsies are tests where a small sample of tissue is taken to check for disease. In the case of a breast biopsy, the sample is checked for possible breast cancer. This law has recently been updated to include comments about breast density, which can affect how clearly doctors can see any abnormalities in the breast on imaging tests.
The MQSA states that a breast biopsy should be done by a doctor who is well-trained and understands how to use the machines to create clear images of the inside of the breast. They should also know the limitations of these machines and be aware of any common errors that can occur when taking these images.
The doctor should also have a thorough knowledge of what a healthy breast looks like, be able to identify the changes that can occur in the breast due to factors like age or hormonal changes, and recognize signs of common breast diseases.
Preparing for Stereotactic and Needle Breast Biopsy
Before a biopsy, your doctor will look over your medical images to plan the best method to reach the tissue they need to sample. They’ll take into account things like major blood vessels and any breast implants you might have. And no matter what, they’ll need you to stay still for at least one hour during the procedure. Different positions may be used depending on what type of biopsy is performed.
For mammogram guided biopsies this might mean lying face down; for ultrasound guided biopsies, you might be lying flat on your back or tilted on your side. To prevent any shifting in the tissue being tested due to gravity, the side being examined will be raised and your arm on the same side placed over or under your head. This helps them get the best sample possible, which is important for getting accurate results from your biopsy.
How is Stereotactic and Needle Breast Biopsy performed
Image-guided biopsies are tests where doctors use imaging tools such as ultrasound, mammography, or magnetic resonance to guide them when they take a sample of cells or tissue from a patient’s body for testing. This can be done using a fine needle to aspirate, or draw out, a sample of cells—however, this process may not provide a reliable diagnosis for breast cancer. Instead, it may be used occasionally to test an unusual cyst or very small lesions, which are tissue changes.
During a fine-needle aspiration, a thin device, like a large needle, is inserted into the area that is being examined; a doctor then moves the needle back and forth slightly while using suction to collect a sample. After the sample is taken, it is spread out on a slide to be viewed later under a microscope.
A vacuum-assisted core biopsy is another option, where multiple samples of tissue can be obtained without needing to remove the biopsy tool each time. The tissue is sucked into the sampler with a vacuum and then cut with a blade. This process is repeated until a sufficient sample is collected.
Alternatively, a spring-loaded core needle biopsy device can be used. When using this method, initial removal of the device after sampling is needed. Despite being simple to use and cheaper, this process might cause some local injury with multiple needle insertions.
Ultrasound-Guided Biopsy provides the advantages of being speedy, avoiding exposure to ionizing radiation, and causing no need for breast compression. Ultrasound imaging will be used to guide the biopsy needle into the target area. After successful sampling, a marker is left at the biopsy site, and manual pressure is applied to prevent the formation of a blood-filled swelling.
Mammography-Guided Biopsy is the preferred choice when lesions are poorly visualized on ultrasound. The disadvantage lies in its cost, the time it takes, and exposure to radiation. Mammographic-guided biopsy firmly holds the breast, and images are taken from different angles before the biopsy needle is inserted. After adequate sampling, a marker is left at the biopsy site.
Magnetic Resonance-Guided Biopsy is chosen when the lesions are detected only by an MRI scan, though it’s the most expensive and time-consuming procedure. The biopsy is usually taken from the side of the breast. After the needle is inserted, a vacuum or spring-loaded device obtains multiple samples. Once the samples are collected, a marker is left in the biopsy area.
Possible Complications of Stereotactic and Needle Breast Biopsy
The usual complications after undergoing a less invasive breast biopsy, known as a stereotactic or needle biopsy, are skin bruising (eccymoses), blood pooling (hematoma), and the movement of the biopsy marker from the original position. Extremely rare but possible aftereffects can be hemothorax (blood in the pleural space in your chest), pneumothorax (air leaks into the space between your lung and chest wall), or hemopneumothorax (a combination of hemothorax and pneumothorax). Thankfully, these situations can usually be dodged with careful techniques. Sometimes, but very rarely, the implant can rupture.
What Else Should I Know About Stereotactic and Needle Breast Biopsy?
It’s crucial to get a detailed diagnosis for breast cancer. This includes knowing the size of the tumor, its characteristics, how invasive it is, whether it has spread to lymph nodes, and if it has spread to other parts of the body (metastasis). This information is key to deciding the best treatment.
Doctors use images taken by machines (imaging) along with examining a tissue sample under a microscope (histopathology) to understand the disease better. Combining these methods helps to target the treatment more precisely. Even when the tumor is still in the breast, doctors can continue to use imaging and take more tissue samples (biopsies) for closer examination.
