Biopsy Technique
Core Needle Biopsy vs. Excisional Biopsy
Core needle biopsy (CNB) advantages over excisional biopsy:
- Just as accurate, reliable, and reproducible
- < 1% complication rate
- Cheaper and faster, shorter recovery time
- Minimal to no cosmetic scar
- Doesn’t change the appearance of mammograms in the future
Rule: Choose the biopsy technique with which you can see the lesion best.
Ultrasound-Guided Biopsy
Patient Positioning
- Position patient to thin the breast
- Lateral lesion: turn patient onto their opposite side
- Inferior lesion: lower the head
- Raising the ipsilateral arm can further thin the tissue
Entry Approach
- Entering through a curve in the lateral breast is easiest (due to natural breast contour)
- The upper inner breast does not have much curve → inferior approach may work best for UIM lesions
Small Lesions
- Use less anesthetic and/or numb the other side of the lesion with a separate needle stick
- Be careful not to inject air
- Target the deeper part of the lesion first (you may obscure the lesion if you biopsy the superficial portion first)
- If you start to lose visualization → clip it in ASAP
- Clip the area before taking all samples to ensure you’re in the right area, then take more passes (just don’t biopsy out the clip)
Aspirating Cystic Lesions
| Aspirate | Next Step |
|---|---|
| Non-bloody + lesion completely resolves | Done — no further workup |
| Bloody + lesion disappears | Clip it + send fluid to cytology |
| Bloody + lesion doesn’t disappear | Core biopsy + clip |
| Purulent aspirate | Send to microbiology culture and sensitivity |
| Green, yellow, or black fluid + lesion disappears | Discard (benign) |
Make sure you biopsy the mass, not the shadowing caused by the mass.
FNA vs. Core Biopsy
- FNA is a good option for a lymph node suspicious for metastatic involvement when there is known breast cancer in the ipsilateral breast
- Otherwise, core biopsy of axillary node or mass is recommended (for diagnosis)
- In the axilla: use a no-throw technique (or FNA if large vessels nearby)
Near Skin/Near Chest Wall
- Can try to displace lesion anteriorly or posteriorly with anesthetic
- If near skin: use lidocaine without epinephrine (near skin); avoid vacuum-assisted device near skin (can pull skin in)
- Can use no-throw technique with open trough if near structures (pec, implants, vessels, skin)
Stereotactic-Guided Biopsy
Minimum Breast Thickness
- Standard needle: 30 mm minimum
- Shortened sampling chamber needle: 20 mm minimum
- Must evaluate breast thickness before biopsy
Making the Breast Thicker
Techniques to increase breast thickness for thin-breast biopsy:
- Roll the breast or tape it to bulge through compression window
- Compression paddle on the other side of the breast (between breast and detector)
- Make a wheel with anesthetic to thicken tissue
- Fire the device outside the breast and dial down to the level of calcs/mass
Lesion Localization in the Trough
- The computer places the lesion in the center of the trough
- Lesions can still be sampled with needle retracted several mm (lesion at deep end of trough instead of center)
- Do NOT want to sample skin or have biopsy needle hit the back detector
- Lateral side-arm attachment: useful for very thin breast; lesion likely near skin, avoid sampling toward skin
Superficial Lesions
- Manually advance needle so trough is just below the skin
- Manufacturers provide plastic pieces to fill part of the trough if sticking out
- Can use skin hooks to pull breast skin to cover the trough
Posterior Lesion Technique
- Prone table: may need to pass patient’s ipsilateral shoulder/arm through the hole as well (also accesses axillary tail)
- Support the arm; squeeze ball may prevent paresthesia
MRI-Guided Biopsy
Posterior Lesion
- Roll patient to the ipsilateral side
- Can use “free hand” technique if grid does not include the lesion (incrementally advance needle toward enhancement)
- Arms by sides or removing padding may help get further posterior
Lesion Doesn’t Enhance on Day of Biopsy
- Run a few more post-contrast series
- If still doesn’t enhance: loosen compression and rerun series a couple minutes later
- Biopsy off landmarks
- If still doesn’t work and lesion was scary → patient returns in 6 months for follow-up MRI
2nd-Look Ultrasound After MRI Finding
- If you think you see a US correlate and biopsy reveals benign pathology → carefully evaluate concordance + 6-month follow-up MRI is likely indicated
Biopsy Clips
Hologic Clips
| Clip | Material | Note |
|---|---|---|
| Mini Cork / SecurMark | Titanium + bioabsorbable suture-like polymer | Don’t use for very superficial biopsies (polymer can hang out the skin) |
| Hourglass / TriMark | Biocompatible titanium | Also Cork TriMark |
| Twirl / UltraCor | Nitinol | Don’t use with nickel allergy; easier to see on US |
| Tumark (Q and U shapes) | — | Easier to see on US |
Bard Clips
- Ribbon (UltraClip) — Titanium with PVA
- Wing (UltraClip) — Inconel 625 with PVA
Biopsy Bleeding Management
Pre-Biopsy
- Ice area to constrict blood vessels
- Patient brings tight-fitting bra (sports bra, no underwire)
- Lidocaine with epi (ok even near skin — skin necrosis is a myth, just be careful with elderly)
- Try to avoid vessels
During and Immediately Post-Biopsy
- Use more lido with epi if needed
- Patient on anticoagulants: hold pressure at least 10 minutes AT the biopsy site (not just skin nick)
Post-Biopsy
- Tight-fitting bra (sports bra) at least all day (maybe sleep in it)
- Forming hematoma → bind with coban or ace bandage; ice immediately
- Avoid anticoagulation medications for 48 hours (depending on medication and reason)
- No heavy exercise or lifting > 10 lbs
- No soaking for 4–5 days
- Can shower after 24 hours
Anticoagulation Guidelines
Per SIR Consensus Guidelines (also see Breast Cancer Treatment):
| Anticoagulant | Hold Time |
|---|---|
| NSAIDs, aspirin (prescribed), fish oil, vitamin E | Do not withhold |
| Aspirin (wellness) | 5 days |
| Clopidogrel (Plavix) | 5 days |
| Rivaroxaban, Apixaban | 3 days |
| Dabigatran, Fondaparinux | 2–3 days |
| Enoxaparin | 12 hrs (hold AM dose) |
| Warfarin | 5 days; correct INR < 2.0 |