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Table 4 Comparisons between patients with small internal mammary lymph nodes (< 1.0 cm) and patients with large internal mammary lymph node (≥1.0 cm)

From: Optimal radiotherapy for patients with internal mammary lymph node metastasis from breast cancer

CharacteristicsNumber of patients (%)p-value
IMN size < 1.0 cm,(n = 42)IMN size ≥1.0 cm,(n = 42)
Age≤40 years20 (47.6%)18 (42.9%)0.827
> 40 years22 (52.4%)24 (57.1%)
Histologic grade1–223 (54.8%)22 (52.4%)0.638
313 (31.0%)17 (40.5%)
Subtypes1)Non-TNBC29 (69.0%)25 (59.5%)0.495
TNBC13 (31.0%)17 (40.5%)
cT stages1–223 (54.8%)24 (57.1%)1.000
3–419 (45.2%)18 (42.9%)
cN stages2b or 3b30 (71.4%)33 (78.6%)0.615
3c12 (28.6%)9 (21.4%)
Malignant cells on FNABx of the IMN(−) or unknown22 (52.4%)22 (52.4%)1.000
(+)20 (47.6%)20 (47.6%)
Extent of IMNSingle ICS20 (47.6%)17 (40.5%)0.661
Multiple ICS22 (52.4%)25 (59.5%)
Neoadjuvant chemotherapyPerformed29 (69.0%)37 (88.1%)0.061
Not performed13 (31.0%)5 (11.9%)
Primary surgeryBCS20 (47.6%)20 (47.6%)1.000
Mastectomy22 (52.4%)22 (52.4%)
Axillary surgeryALND39 (92.9%)35 (83.3%)0.313
SLNB3 (7.1%)7 (16.7%)
EQD2 of the IMN2)50.0–63.5 Gy20 (47.6%)15 (35.7%)0.376
63.6–70.4 Gy22 (52.4%)27 (64.3%)
  1. 1)TNBC was defined as tumors that were negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 on immunohistochemical staining of the breast tumor
  2. 2)Radiotherapy dose was calculated using the EQD2 assuming the α/β ratio of 3.5 Gy
  3. Abbreviations: IMN Internal mammary node; TNBC Triple-negative breast cancer, FNABx Fine needle aspiration biopsy, ICS Intercostal space, BCS Breast conserving surgery, ALND Axillary lymph node dissection, SLNB Sentinel lymph node biopsy, EQD2 Biologically equivalent dose in 2 Gy fractions