Breast Cancer Clinical Management and Staging

N (Regional Lymph Nodes)

The N category describes whether the cancer has spread to nearby lymph nodes. It is divided into clinical (cN) and pathologic (pN) assessments.

• N1: Involves movable axillary lymph nodes or microscopic metastases (micrometastases).
• N2: Involves fixed or matted axillary nodes, or involvement of the internal mammary nodes.
• N3: Involves extensive involvement, including infraclavicular, supraclavicular, or extensive internal mammary/axillary nodes.

M (Distant Metastasis)

The M category indicates whether the cancer has spread to distant organs (e.g., lungs, liver, bones).

• M0: No evidence of distant metastasis.
• M1: Distant metastasis is present, which classifies the disease as Stage IV.

Specialized Clinical Presentations

Certain presentations of breast cancer require immediate recognition because they necessitate different surgical and systemic approaches.

Inflammatory Breast Cancer (IBC)

IBC is a highly aggressive clinical presentation characterized by a rapid onset (typically $\leq 6$ months) of erythema (redness) and edema, often described as peau d'orange (skin resembling an orange peel). This occurs when cancer cells block the lymphatic vessels in the skin.

Management of IBC differs significantly from standard breast cancer:

• Preoperative Systemic Therapy: Patients typically receive chemotherapy before any surgical intervention.
• Surgery: If there is no response to systemic therapy, a total mastectomy is required. Notably, skin-sparing or nipple-sparing mastectomies are contraindicated in IBC due to the high risk of skin involvement.
• Adjuvant Therapy: Treatment usually includes level I/II axillary dissection and radiation therapy.

Paget Disease of the Nipple

Paget disease presents as an eczematous-like lesion, such as ulceration or scaling, on the nipple or areola. Management options include:

• Central lumpectomy (breast-conservation therapy) followed by radiation therapy.
• Total mastectomy.

Management in Pregnancy

Managing breast cancer during pregnancy requires a highly coordinated multidisciplinary approach to balance maternal oncologic care with fetal safety.

Clinical Pearl: The Trimester Rule When managing pregnant patients, the timing of systemic therapy is critical. Chemotherapy is generally contraindicated during the first trimester due to the high risk of teratogenicity and fetal loss. However, it can be safely administered during the second and third trimesters.

The following table summarizes treatment considerations during pregnancy:

Summary of Treatment Modalities

Standard breast cancer treatment often involves a combination of the following:

• Systemic Therapy: Includes chemotherapy, targeted therapies, and endocrine therapy to treat the disease throughout the body.
• Breast-Conservation Therapy (BCS): Involves removing the tumor while preserving the breast, usually followed by radiation therapy.
• Mastectomy: The surgical removal of breast tissue, which may be required in cases of large tumors, multi-centric disease, or specific subtypes like IBC.