Breast Cancer Overview

Breast cancer is a type of cancer that originates in the cells of the breast. It is one of the most common cancers among women worldwide, though it can also occur in men.

Understanding the normal anatomy of the breast helps in understanding where cancer can arise:

• Lobules: These are the milk-producing glands of the breast.
• Ducts: These are tubes that carry milk from the lobules to the nipple. Most breast cancers begin in the ducts.
• Connective Tissue: Includes fibrous tissue and fatty tissue that surround the lobules and ducts, giving the breast its shape.
• Blood Vessels and Lymphatic Vessels: The breast has a rich blood supply and a network of lymphatic vessels and lymph nodes. Lymph nodes are small, bean-shaped glands part of the body's immune system. Breast cancer cells can travel through these lymphatic vessels and spread to nearby lymph nodes, most commonly in the armpit (axillary lymph nodes).

Breast cancer is characterized by the uncontrolled growth of abnormal cells. Pathologists examine tissue samples (biopsies) under a microscope to determine the type of cancer and its characteristics.

Main Types:

Less Common and Special Types:

While breast cancer can sometimes be asymptomatic, common signs and symptoms include:

• A new lump or mass in the breast or underarm (armpit) - most common symptom.
• Change in size or shape of the breast.
• Dimpling of the skin (orange peel appearance).
• Redness or flaky skin on the nipple or breast.
• Pulling in of the nipple or nipple discharge other than breast milk (especially if bloody).
• Breast or nipple pain that doesn't go away.

Risk factors increase the likelihood of breast cancer but don't guarantee it:

• Gender: Being female is the biggest risk factor.
• Age: Risk increases especially after 50 years old.
• Genetics: Inherited mutations (e.g., BRCA1/BRCA2) and family history of breast or ovarian cancer.
• Reproductive History: Early menstruation, late menopause, no full-term pregnancy, or first pregnancy after age 30.
• Breast Density: Dense breasts complicate mammograms and increase risk.
• Personal History: Previous breast cancer increases risk in the other breast.
• Radiation Exposure: Chest radiation at young age.
• Hormone Therapy: Combined estrogen-progestin therapy after menopause.
• Obesity: Particularly after menopause.
• Alcohol Consumption: Higher intake increases risk.
• Lack of Physical Activity.

Common diagnostic methods include:

• Clinical Breast Exam (CBE): Physical examination by a doctor.
• Mammogram: X-ray of the breast for screening and diagnosis.
• Breast Ultrasound: Sound waves create images, used to evaluate abnormalities.
• Breast MRI: Uses magnets and radio waves, often for high-risk or detailed evaluation.
• Biopsy: Tissue sample removal for microscopic examination to confirm cancer type.

Staging determines cancer size, lymph node involvement, and distant spread, guiding treatment and prognosis. The TNM system is common:

• Stage 0: DCIS (non-invasive).
• Stages I-III: Invasive cancer localized or with nearby lymph node spread.
• Stage IV: Metastatic cancer spread to distant organs (bones, lungs, liver, brain).

Treatment depends on cancer type, stage, hormone receptor and HER2 status, and patient health. Common treatments include:

• Surgery: Lumpectomy, mastectomy, lymph node dissection.
• Radiation Therapy: High-energy rays to kill cancer cells.
• Chemotherapy: Drugs to kill cancer cells systemically.
• Hormone Therapy: For hormone receptor-positive cancers.
• Targeted Therapy: Drugs targeting specific cancer cell features (e.g., HER2).
• Immunotherapy: Boosts immune system to fight cancer.

Prognosis depends on stage, cancer type, and treatment response. Early localized breast cancer has a high survival rate. Advances in detection and treatment have improved outcomes greatly.