|
| | Metaplastic breast carcinoma | Invasive ductal carcinoma |
|
| Clinicopathological features | | |
| Incidence | 0.2–1% [1] | 85% |
| Age of presentation | Mean age 46–68, similar to TNBC [2, 14] | Mean age 45–60 |
| Size (mean) | 3.9–5.0 cm [1] | 2.1–2.3 cm [1] |
| Axillary lymph node metastasis | Lower incidence, 6–28% [1, 2, 13] | 34–50% [1, 2] |
| Hematogenous spread | More likely, preferentially affecting lung and brain (65%), and less likely in bone [1] | Less likely, preferentially affecting bone (60%), lung, and brain [1] |
| Stage at presentation | | |
| Stage II or higher | >70% [3] | 50% [3] |
| Stages III-IV | 15.2–35.2% [1, 2, 14] | 11–11.8% [1, 2] |
|
| Imaging | Benign (circumscribed, round, or oval on ultrasound, T2 hyperintensity on MRI) or malignant appearance [2, 13] | Malignant appearance (irregular or circumscribed with spicules) |
|
| Biomarkers | | |
| ER/PR/HER2 triple negative | 70–100% [13] | 15% [4] |
| EGFR | Overexpression 93.9% [9], amplification 30% [2] | Overexpression 21.6% [9] |
| PIK3CA/PTEN mutation | 47.4%/5.3% [8] | 21.4%/2.3% [8] |
| Wnt/β-catenin deregulation | 92% [7] | 35% in IDC, 36% in benign breast [15] |
| p53 mutation and overexpression | 50.9–63.8% [1, 2, 9] | 28.8–38.8% [1, 2, 9] |
| Ki-67 (>=14%) | 87.2% [1] | 61.1–63.4% [1] |
|
| X-chromosome inactivation pattern | 100% (4/4) clonal [5] | 33% (4/12) mosaic (polyclonal) [6] |
|
| Chemotherapy | | |
| Frequency [2, 13] | Twice likely with frequency of 53.4% in stage matched cases and 33–86% overall | Less likely with frequency of 42.1% in stage matched cases |
Response to conventional taxane,
anthracycline chemotherapy [2] | Neoadjuvant: 10% response
Adjuvant: 10–17.6% response | Neoadjuvant: 11–45% response in TNBC
Adjuvant: 21–75% response |
Response to stem cell targeting
adjuvant chemotherapy [10, 11] | 40–42% complete and partial pathological response | |
Response to cisplatin containing
regimen | Adjuvant: 12% decreased relapse rate compared to taxane/anthracycline/cyclophosphamide regimen [1] | Neoadjuvant: 44.2% complete pathological response in TNBC compared to anthracycline (26.8%) and taxane (30.5%) group [4] |
|
| Radiotherapy [3] | Frequency of 38.6–49.1%
16.2% decreased risk of death in lumpectomy;
2.4% decreased risk of death in mastectomy | Frequency of 23%
17% decreased risk of death in lumpectomy |
|
| Prognosis | | |
| Recurrent rate | 60% usually within 5 years [13] | 20% within a variable length of time [13] |
| Five-year survival | 45.5%–63% [1, 13] | 60.3% in TNBC and 71.2%–92% in IDC [1, 13] |
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