Post-Operative Breast
Definitions
| Term | Definition |
|---|---|
| Recurrence | Same histopathology as original malignancy |
| Second primary | Histopathologically distinct from first malignancy |
| Interval cancer | Detected because patient presented with symptoms between set screening intervals |
| Surveillance | Routine diagnostic imaging/screening to detect local recurrence before any symptoms |
Board Pearl
Recurrence vs. second primary: Most ipsilateral tumors within first 5 years post-BCT are recurrences (especially same quadrant). Second primary more likely if occurs > 5 years post-BCT, in ipsilateral breast but different quadrant, or in contralateral breast.
Post-Lumpectomy Changes
Mammography Timeline
- First post-op mammo: 6–12 months
- Pre-radiation mammo: Look for residual calcs — calcs in the surgical bed have a 60% recurrence rate vs. 6% overall. If calcs not described on pre-radiation mammo but appear after → patient may need mastectomy.
- Architectural distortion at lumpectomy scar should stabilize by 2 years, then continue to decrease. Should have fat within it on mammo.
Radiation Therapy Changes (Mammography)
Post-RT changes are edema → fibrosis. Appear as skin and trabecular (Cooper’s ligaments) thickening.
| Timepoint | Expected Changes |
|---|---|
| First 6 months | Peak of edema, skin thickening, fluid collections |
| 6–12 months | Edema stabilizing, calcs begin appearing |
| 12–24 months | Skin thickening stabilizing |
| 2–3 years | Changes should stabilize (edema, skin thickening) |
| 3+ years | Calcs continue developing; scarring/fibrosis predominates |
- 28% develop dystrophic calcs within first 6–12 months post-XRT
- Calcs associated with fat necrosis: round/punctate, coarse heterogeneous, rim calcs (oil cysts)
- US: concave AD with shadowing, extends to skin scar
- MRI: post-op changes and fat necrosis can enhance for up to 18 months — if in doubt, biopsy
Red Flag
If skin/trabecular thickening decreases and stabilizes, then gets worse again → consider inflammatory breast cancer, also benign causes: venous congestion, CHF/renal failure, infection. New increase in skin/trabecular thickening/edema after it peaks is not normal.
Surgical Procedures — Imaging Appearance
Reduction Mammoplasty
- Fatty tissue and skin removed from inferior breast
- Non-anatomic distribution of remaining breast tissue
- Scarring mostly along inferior breast
- “Swirling” appearance on MLO
- Can get isolated islands of breast tissue and dermal calcs in scar tissue
- Oil cysts common; epidermal inclusion cysts if skin pulled into breast
Mastopexy (Breast Lift)
- Skin gets removed inferiorly
- Small 12:00 incision to lift areola
- Similar scar appearance to reduction on mammo
Detecting Recurrent Disease
Timing
- Local recurrence affects 6–8% of women post-BCT
- Occurs between 1 and 7 years post-lumpectomy, peak at 4 years
- Recurrence within first 2 years is uncommon
- Without RT: 30–40% local recurrence rate
Patterns by Modality
Mammography:
- Recurrence usually in same ductal system (segment) as original cancer
- Look: scar → breast between scar and nipple → scar and chest wall
- Lumpectomy bed scar getting thicker or more dense → suspicious (especially focal thickening)
- Diffuse thickening can be seen with fat necrosis (look for central lucency)
MRI:
- Scars > couple years usually do not show suspicious enhancement
- Minimal linear enhancement or residual seroma = not uncommon
- Mass or non-mass enhancement near lumpectomy bed = concerning for recurrence
- Fat necrosis mimics cancer on all modalities:
- Look for T1 non-fat-sat sequence to find central fat
- MRI can show irregular enhancing mass without definite central fat → may need biopsy
Ultrasound:
- Seromas: should slowly resolve, some persist for years and years
- Seroma that increases in size → suspicious (if stable/resolved then increases)
- Local recurrence can occur in the dermis, in/near scar → can mimic sebaceous cyst
DCIS Recurrence
- 75% appear as calcifications on mammo
- Suspicious calcs develop earlier (2-year average) vs. benign post-treatment calcs (4-year average)
- 50% of DCIS recurrences will have an invasive component
Recurrence in Tissue Flap
- Occurs in residual breast tissue, NOT the relocated flap fat
- Many women have skin-sparing mastectomy → local recurrence typically along subcutaneous scar line
- Don’t typically screen these women (controversial)
Recurrence Risk Factors (Post-BCT)
Higher recurrence risk:
- Age < 40 years
- ER-negative tumor
- Lymphovascular invasion
- Multifocal disease
- Close margins (< 2mm for DCIS) or positive margins for invasive cancer
- No endocrine therapy with ER+ disease
- No chemotherapy with invasive disease
- No XRT boost to lumpectomy site
Mastectomy
- With or without reconstruction: if all breast tissue taken, does NOT require follow-up screening
- Acellular dermal matrix (ADM): surgical mesh of human/animal skin with cells removed; higher complication rate but better cosmesis; may prevent capsular contracture
Key Numbers
| Fact | Value |
|---|---|
| Post-BCT recurrence rate (without XRT) | 25–36% |
| Post-BCT recurrence rate (with XRT) | 6–14% |
| Local recurrence affects | 6–8% post-BCT |
| Peak recurrence year | 4 years |
| Recurrence rate per year for 10 years | 1–2%/year |
| Risk peaks years | 2–6 |
| Dystrophic calcs post-XRT | 28% within 6–12 months |
| RT changes peak on mammo | First post-RT mammo (~6 months, or 12 months if 6-month not done) |
| APBI vs WBI recurrence | APBI higher recurrence, no difference in OS |
| MRI enhancement post-op/fat necrosis | Up to 18 months |
| Residual calcs in surgical bed recurrence rate | 60% |