Norm of Stereotactic Breast Biopsy
Atypical or malignant cells.
Description of Stereotactic Breast Biopsy
Stereotactic breast biopsy is a radiograph-guided method of localizing and sampling nonpalpable breast lesions that are discovered on mammography and considered to be suspicious for malignancy. The position of the lesion in the breast can be calculated relative to a fixed grid and a needle placed within the lesion with direct confirmation of its position on a stereotactic radiograph. The placement is accurate to within 2 mm. Stereotactic breast biopsy can be performed by means of fine-needle aspiration cytology or core needle histology.
Professional Considerations of Stereotactic Breast Biopsy
Consent form IS required.
Bruising, infection at needle aspiration site, vasovagal reaction.
Large, abnormal breast tissue area.
During pregnancy, risks of cumulative radiation exposure to the fetus from this and other previous or future imaging studies must be weighed against the benefits of the procedure. Although formal limits for client exposure are relative to this risk:benefit comparison, the United States Nuclear Regulatory Commission requires that the cumulative dose equivalent to an embryo/ fetus from occupational exposure not exceed 0.5 rem (5 mSv). Radiation dosage to the fetus is proportional to the distance of the anatomy studied from the abdomen and decreases as pregnancy progresses. For pregnant clients, consult the radiologist/ radiology department to obtain estimated fetal radiation exposure from this procedure.
- This procedure is performed by a radiologist with mammographic experience.
- Equipment is assembled according to the type of biopsy (fine-needle aspiration or core needle) and the radiologist's preference.
- The client is assessed for any allergies, use of anticoagulants or antiplatelet agents, or bleeding disorders.
- Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.
- The client is positioned prone on the x-ray table with the breasts hanging down for the mammogram films and biopsy. An upright seated position with lateral arm support may also be used, but is associated with a higher incidence of vasovagal reactions.
- The skin is prepared according to the radiologist's preference and institutional policy.
- A local anesthetic is injected into the biopsy site.
- A small incision is made at the site of needle insertion.
- The needle (either a 14-gauge automated needle or an 11- to 14-gauge vacuum-assisted biopsy probe) is inserted percutaneously into the lesion with placement confirmed by radiography.
- Three or more samples are taken from different positions in the lesion. At least 12 samples are required for best diagnostic accuracy. The first sample is usually taken from the core of the lesion, followed by samples taken from the periphery.
- Metallic clips may be placed within the breast to mark the biopsy site for easy identification should later biopsy be needed.
- The specimen obtained from core needle biopsy is placed in formalin and sent immediately to the laboratory.
- The specimen obtained from fine-needle aspiration is fixed on cytology slides and sent immediately to the laboratory.
- Place Steri-Strips and a pressure dressing over the site.
- If metal clips were placed, two orthogonal planes should be taken via mammogram to confirm clip location for later comparison.
Client and Family Teaching
- The client may eat or drink as usual.
- The procedure generally takes 1 hour.
- Most individuals are able to return to their usual routine, including driving or work, after the procedure.
- The dressing may be removed the next day.
- There may be some tenderness, swelling, bruising, or slight bleeding at the site. An ice pack or non-aspirin pain reliever will help to relieve these symptoms.
- If the biopsy diagnosis is benign, routine mammograms should be continued.
Factors That Affect Results
- Core needle biopsy yields better diagnostic results than does fine-needle aspiration. All specimens taken must be examined to avoid false-negative results.
- Needle placement can be inaccurate and yield a false-negative result if the breast tissue is displaced during biopsy.
- Physician experience with at least 5–14 prior biopsies of this type significantly improves the diagnostic accuracy of the procedure.
- If inadequate tissue was obtained or if a malignancy is suspected but not confirmed, an open surgical biopsy is recommended. Open surgical biopsy is also recommended if atypical cells are identified.
- Although complications from this procedure may include infection and hematoma, the complication rate is low.
- Results from either fine-needle aspiration or core needle biopsy are available within 24 hours.
- A 1-year follow-up mammography is recommended for benign lesions.