https://my.clevelandclinic.org/health/diagnostics/24204-breast-biopsy-overview

In the clinical practice of breast fine-needle aspiration biopsy, although the technique itself is important, the skills of the operator and the standardized procedures are the decisive factors for ensuring the accuracy of the diagnosis. Especially in fine-needle aspiration performed under ultrasound guidance, it can be regarded as a "precise-guided" surgery, and each step requires strict quality control.

Preoperative Preparation: Imaging Assessment and Risk Avoidance

A successful puncture begins with thorough preoperative preparation. First, the operator must carefully review the patient's breast ultrasound, mammography, or MRI images to determine the location, size, shape, depth of the target lesion, as well as its relationship with surrounding important structures (such as the chest wall, major blood vessels, and implanted prostheses). For tiny calcification foci, it is necessary to confirm whether they are visible on the ultrasound; if not, then X-ray stereotactic positioning should be adopted.

Secondly, the patient's coagulation function needs to be evaluated. Although the risk of bleeding from fine needle puncture is extremely low, for patients taking anticoagulant drugs (such as aspirin, clopidogrel, warfarin), the pros and cons should be weighed, and in necessary cases, the medication should be stopped or the treatment plan adjusted under the guidance of a specialist. At the same time, a detailed inquiry about allergy history is required, especially regarding the allergy to local anesthetics (lidocaine).

Intraoperative Procedures: Ultrasound Guidance and Puncture Techniques

This is the core part of the entire process, testing the doctor's hand-eye coordination skills and spatial imagination.

1. Positioning and Disinfection: The patient is usually placed in the supine position, with the affected arm raised above the head, fully exposing the armpit and breast. Routine disinfection and draping are carried out to establish a sterile area.
2. Ultrasound Examination and Localization: Use a high-frequency linear array probe (7.5-15 MHz) to conduct a comprehensive scan again, finding the best display section for the lesion. Fix the probe, positioning the lesion at the center of the screen, and plan the needle insertion route. The ideal needle insertion path should be parallel to the long axis of the probe, allowing the needle body to be fully visible.
3. Local Anesthesia: Apply 1% lidocaine at the puncture site to form a wheal, and infiltrate the subcutaneous tissue and superficial fascia along the predetermined puncture path. Be careful not to inject the anesthetic into the lesion itself to avoid diluting the cellular components.
4. Puncture and Aspiration: This is the most critical step. The operator holds the probe steady with one hand and holds the fine needle connected to a 10ml or 20ml syringe with the other hand. Under real-time ultrasound monitoring, insert the needle quickly into the skin, then slowly advance it to the edge of the lesion. After confirming that the needle tip is within the target, pull the syringe plunger to a 3-5ml negative pressure, repeatedly lift and insert the needle within the lesion (about 10-20 times), and change the needle tip direction to obtain cells from different areas. Before releasing the negative pressure, stop lifting and inserting the needle to ensure the needle tip remains within the lesion, then slowly withdraw the needle. The purpose of releasing the negative pressure is to prevent cells from being sucked into the syringe barrel and lost.
5. Sample Processing: After withdrawing the needle, immediately push the trace blood-like tissue fluid in the needle core onto a slide and spread it evenly with another slide to make a thin-layer smear. The smear should be quickly fixed in 95% alcohol or air-dried for subsequent staining (such as Papanicolaou staining or Diff-Quik staining).

Postoperative Management and Quality Indicators

After the puncture is completed, apply a gauze to press the puncture site for 5 to 10 minutes to stop the bleeding. Instruct the patient to avoid strenuous exercise and taking a bath within 24 hours. Record the details of the puncture process, such as the number of needle insertions, any complications (such as hematoma, pneumothorax), and the appearance of the sample (blood-like, pus-like, dry clot, etc.).

The core indicators for evaluating the quality of breast fine-needle aspiration biopsy are:

• Specimen Satisfaction: The qualified smear should contain a sufficient number of clear and well-organized epithelial cell clusters. The dissatisfaction rate should be kept at a low level (typically <10%).
• False Negative Rate: This refers to cases where the biopsy result is benign, but the final surgical pathology confirms it as malignant. Ideally, this rate should be lower than 2%.
• Incidence of Complications: The incidence of severe complications (such as hematomas requiring intervention, infections, pneumothorax) should approach zero.

Continuous Improvement: From Experience to Evidence-Based Approach

To enhance the overall quality, medical institutions should establish a regular quality control meeting system. Review and analyze all false-negative and unsatisfactory cases, identify the causes (whether it is due to the small size of the lesion, an improper location, or an issue with the operation technique?), and conduct targeted training. Additionally, implement the rapid on-site assessment technique, where cytological technicians immediately perform rapid staining and preliminary assessment of the smears at the puncture site. This enables immediate determination of whether the specimen is satisfactory and allows for on-the-spot re-puncture when necessary, significantly improving the diagnostic efficiency.

In conclusion, breast fine-needle aspiration biopsy is not merely a technique, but also a set of standardized operational procedures that must be strictly followed. Only by integrating superb technical skills, precise imaging guidance, and strict quality control can its clinical value be maximized, providing reliable diagnostic evidence for patients.