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Locally advanced breast cancer (LABC) refers to stage III breast cancer that has extensive local and/or regional spread but no distant metastasis (M0). It represents a heterogeneous group of aggressive tumors that require multimodal treatment.

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AJCC 8th edition – Stage III Definition:

Stage Description
IIIA Tumor of any size with ≥4 axillary lymph nodes, or infraclavicular/internal mammary nodes
IIIB Tumor with skin/chest wall invasion (e.g., peau d’orange, ulceration, pectoral invasion)
IIIC Extensive nodal disease: ipsilateral supraclavicular, infraclavicular, axillary, and/or internal mammary nodes

Clinical Features

Radiology

Modality Imaging features
Mammography • Large, irregular or spiculated mass
• Skin/nipple retraction
• Microcalcifications
• Axillary adenopathy
• Skin thickening >3 mm
US • Hypoechoic, irregular mass with angular or indistinct margins
• Cortical thickening of lymph nodes, loss of fatty hilum
• May show pectoral muscle/chest wall invasion
MR Post-therapy MRI evaluates response to neoadjuvant chemotherapy
• Tumor extent, multifocality
• Chest wall or skin invasion
• Non-mass enhancement in DCIS component
• Enhancing nodal disease
PET-CT PET-CT has high sensitivity for nodal and distant disease

![CT and the local finding of locally advanced breast cancer (LABC) involving the skin surface (68 × 33 × 70 mm) with ipsilateral (12 × 10 × 12 mm and 11 × 7 × 9 mm) and contralateral (47 × 29 × 51 mm) breast metastases. (A) Axial image. Red arrow shows the primary breast tumor. (B) Axial image. Red and green arrows show the primary breast tumor and ipsilateral breast metastasis, respectively. (C) Axial image. Blue and yellow arrows show the ipsilateral and contralateral breast metastases, respectively. (D) The local findings of LABC involving the skin surface.

Shiba S, Watanabe T, Takuya Kaminuma, et al. Locally Advanced Breast Cancer Involving the Skin Surface Treated With Radiation Therapy Using a Hydrogen Peroxide Solution–Soaked Gauze Bolus: A Case Report. Advances in Radiation Oncology. 2022;7(3):100894-100894. doi:https://doi.org/10.1016/j.adro.2022.100894](attachment:df6f1182-8a3e-45bf-88de-a2273080ddb0:gr1_lrg.jpg)

CT and the local finding of locally advanced breast cancer (LABC) involving the skin surface (68 × 33 × 70 mm) with ipsilateral (12 × 10 × 12 mm and 11 × 7 × 9 mm) and contralateral (47 × 29 × 51 mm) breast metastases. (A) Axial image. Red arrow shows the primary breast tumor. (B) Axial image. Red and green arrows show the primary breast tumor and ipsilateral breast metastasis, respectively. (C) Axial image. Blue and yellow arrows show the ipsilateral and contralateral breast metastases, respectively. (D) The local findings of LABC involving the skin surface.

Shiba S, Watanabe T, Takuya Kaminuma, et al. Locally Advanced Breast Cancer Involving the Skin Surface Treated With Radiation Therapy Using a Hydrogen Peroxide Solution–Soaked Gauze Bolus: A Case Report. Advances in Radiation Oncology. 2022;7(3):100894-100894. doi:https://doi.org/10.1016/j.adro.2022.100894

Differentials

Entity Key Features
‣ Skin erythema, edema, dermal lymphatic invasion; rapid progression
Locally recurrent breast cancer History of prior treatment; scar tissue at site
‣ Rapid growth; well-circumscribed; usually benign or borderline

Histopathology