Makindo Medical Notes.com

Breast cancer is the most common malignancy among women worldwide and represents a significant clinical challenge. This overview provides essential information for clinicians regarding the pathophysiology, diagnosis, treatment, and management of breast cancer.

About

• Seen at all ages in adults. Commonest in women over age 70.

Aetiology

Breast cancer arises from the epithelial cells lining the ducts or lobules of the breast. The transformation of these cells involves multiple genetic mutations that lead to uncontrolled cell proliferation. Key factors involved in the development of breast cancer include

• Hormonal influence: Oestrogen and progesterone play a critical role in the pathogenesis of hormone receptor-positive breast cancers.
• Genetic mutations: BRCA1 and BRCA2 gene mutations significantly increase the risk of developing breast cancer.
• HER2 overexpression: HER2-positive breast cancers are characterized by overexpression of the HER2 protein, leading to aggressive tumour growth.

Increased Risks

Clinical

The clinical presentation of breast cancer can vary widely. Common symptoms and signs include:

• Painless lump or mass in the breast that enlarges and may be fixed
• Skin tethering/dimpling/altered contour
• Nipple retraction or discharge
• Skin changes over the breast, such as dimpling or redness
• Axillary lymphadenopathy
• In advanced cases, symptoms related to metastasis (e.g., bone pain, shortness of breath, jaundice)

Differentials

• Fibroadenoma: mobile small benign lesion
• Fibrocystic disease a benign breast condition
• Breast abscess: settles with antibiotics. If fails to settle then escalate.

Breast Imaging: crucial role in the diagnosis and staging of breast cancer.

• Mammography: primary screening tool particularly effective in detecting early-stage disease.
• Ultrasound: for characterizing breast masses, especially in younger women with dense breast tissue.
• Magnetic Resonance Imaging (MRI): detailed images, often used in high-risk patients or for evaluating the extent of disease.

Biopsy: Histopathological is essential for confirming the diagnosis

• Core needle biopsy: most common method, allows for histologic and molecular analysis.
• Fine needle aspiration (FNA): for cytologic evaluation but not as good as core biopsy.
• Excisional biopsy: Removal of the entire lesion.

Histopathological Analysis: reveals the type and grade of the breast cancer

• Invasive Ductal Carcinoma (IDC): The most common type of breast cancer, accounting for approximately 70-80% of cases.
• Invasive Lobular Carcinoma (ILC): The second most common type, often presenting as a diffusely infiltrative pattern.
• Ductal Carcinoma In Situ (DCIS): A non-invasive form confined to the ductal system, considered a precursor to invasive cancer.

Further Investigations

• FBC, U&E, LFTs
• CXR: Effusion, Lymphangitis carcinomatosis
• Biopsy from the breast, HER2 and oestrogen receptor status
• USS liver scan, Bone scan

Treatment: multimodal and depends on the stage, histological subtype, receptor status, and patient factors

Surgery

• Breast-conserving surgery (lumpectomy): removal of the tumour with a margin of normal tissue, typically followed by radiation therapy.
• Mastectomy: Complete removal of the breast tissue, larger tumours, multifocal disease, or patient preference.
• Axillary lymph node dissection or sentinel lymph node biopsy: Performed to assess the extent of nodal involvement.

Radiation Therapy

Adjuvant radiation therapy is commonly used after breast-conserving surgery to reduce the risk of local recurrence. It may also be used in advanced cases for palliation.

Systemic Therapy

Systemic therapy includes chaemotherapy, hormone therapy, and targeted therapy. The choice of therapy is guided by the tumour's receptor status and other molecular characteristics:

• Chemotherapy: higher-grade or node-positive cancers, as well as HER2-positive and triple-negative breast cancers.
• Hormone therapy: hormone receptor-positive cancers, options include tamoxifen, aromatase inhibitors, and ovarian suppression.
• Targeted therapy: HER2-positive cancers may be treated with trastuzumab (Herceptin) and other HER2-targeted agents.

Prognosis

The prognosis of breast cancer depends on several factors, including the stage at diagnosis, tumour grade, hormone receptor status, and HER2 status. Early detection and treatment significantly improve outcomes, with 5-year survival rates exceeding 90% for localized breast cancer.

Follow-Up and Survivorship

Long-term follow-up is essential for detecting recurrences and managing the side effects of treatment. Follow-up care includes regular physical examinations, imaging studies, and monitoring for late effects of therapy, such as cardiotoxicity from chaemotherapy or radiation.

Conclusion

Breast cancer management requires a multidisciplinary approach involving surgery, medical oncology, radiation oncology, and supportive care. Staying updated on the latest guidelines and advancements in breast cancer treatment is crucial for providing optimal patient care.