Breast Cancer

Symptoms

• A new lump or mass in the breast or underarm area (axilla). These lumps can be hard, painless, and have irregular edges, but may also be soft, round, or tender.
• Swelling of all or part of a breast, even if no lump is felt.
• Skin irritation or dimpling, which can sometimes resemble an orange peel texture (known as 'peau d'orange').
• Pain in the breast or nipple.
• Nipple retraction, where the nipple turns inward.
• Redness (erythema), scaliness, or thickening of the nipple or breast skin.
• Nipple discharge other than breast milk, including blood.
• Unexplained back pain, which can be a sign of cancer that has spread (metastatic disease).
• Changes in breast size or shape.
• Rapid onset of redness, swelling, warmth, and tenderness in the breast, with skin that may appear pitted or ridged (symptoms of inflammatory breast cancer, which requires urgent evaluation).
• Bone pain, shortness of breath, jaundice, or neurological symptoms like seizures or severe headaches, which require urgent medical attention as they can indicate metastatic disease.

Causes & Risk Factors

• Breast cancer is caused by damage (mutations) to the DNA of breast cells. These mutations can be inherited or, more commonly, acquired during a person's lifetime.
• Approximately 5-10% of breast cancers are hereditary, resulting from inherited mutations passed down from a parent. The most well-known are mutations in the BRCA1 and BRCA2 genes. These genes are tumor suppressors, and a mutation impairs their ability to repair DNA damage, allowing other genetic alterations to accumulate, which can lead to cancer.
• About 90% of breast cancers are due to acquired mutations that occur from aging, environmental exposures, and lifestyle factors. The exact cause of these acquired mutations is not fully understood.
• The development of breast cancer is a complex process involving the accumulation of multiple genetic and epigenetic changes.
• Hormones play a role, as estrogen can promote the growth of breast cancer cells, especially those that are estrogen receptor-positive (ER-positive).
• In some breast cancers, an excess of the HER2 protein promotes cancer cell growth.
• Being female is the primary risk factor.
• The risk increases with age, with most cases diagnosed in women over 50.
• Inherited mutations in genes such as BRCA1, BRCA2, PALB2, CHEK2, ATM, and TP53.
• Having a first-degree relative (mother, sister, daughter) with breast cancer, particularly if diagnosed at a young age.
• A previous diagnosis of breast cancer or certain non-cancerous breast diseases (e.g., atypical hyperplasia, Lobular Carcinoma In Situ (LCIS)).
• Early menarche (starting periods before age 12) or late menopause (after age 55).
• Having more glandular and fibrous tissue compared to fatty tissue on a mammogram (dense breast tissue).
• White women are slightly more likely to develop breast cancer than Black, Hispanic, and Asian women, but Black women are more likely to die from the disease.
• Previous radiation therapy to the chest or face before age 30.
• Never having a full-term pregnancy (nulliparity) or having your first full-term pregnancy after age 30.
• Being overweight or obese after menopause (postmenopausal obesity).
• The risk increases with the amount of alcohol consumed.
• Lack of regular physical activity.
• Use of combined postmenopausal hormone therapy (estrogen and progestin).
• A small, temporary risk associated with some oral contraceptives that decreases after stopping.
• Tobacco smoking is now classified as a cause of breast cancer.
• Night shift work is classified as a probable carcinogen, but evidence from large studies remains inconsistent.

Diagnosis

• The standard diagnostic approach is the 'triple assessment' or 'triple test', which includes: clinical history and physical examination, imaging (mammography and/or ultrasound), and biopsy for pathological assessment.
• Your doctor will ask about your symptoms, personal medical history, family history of cancers, reproductive and menstrual history, and medication history.
• A clinical breast exam (CBE) involves visually inspecting your breasts and gently feeling (palpating) your entire breast and the lymph nodes in your armpit and above your collarbone to check for any masses or swollen lymph nodes.
• Mammography is an X-ray of the breast, used for both screening and diagnosis.
• Ultrasound uses sound waves to create images, often used to further evaluate abnormalities and distinguish between solid masses and fluid-filled cysts.
• Magnetic Resonance Imaging (MRI) is used in specific situations, such as screening high-risk women, assessing the extent of disease, or evaluating treatment response.
• Biopsy is the definitive diagnostic procedure, where a tissue sample is removed for microscopic examination. Types include Fine-Needle Aspiration (FNA), Core Needle Biopsy (CNB – preferred), and Surgical (Excisional) Biopsy.
• A pathology report analyzes the biopsy sample to determine cancer type (histology), tumor grade, hormone receptor status (ER, PR), HER2 status, and proliferation rate (e.g., Ki-67 index).
• The TNM Staging System (AJCC) describes the extent of cancer based on the size and extent of the primary Tumor (T), spread to nearby lymph Nodes (N), and Metastasis (M) to distant sites.
• Staging may involve blood tests (like liver function tests) and imaging scans (such as CT scans, bone scans, or PET-CT scans) to check for metastasis.
• Conditions with similar symptoms that may be considered in a differential diagnosis include fibroadenoma, breast cyst, fat necrosis, mastitis or breast abscess, fibrocystic breast changes, and lipoma.

Treatment Options

• Breast cancer treatment is multidisciplinary and tailored to your specific cancer subtype, stage, tumor grade, genomic profile, and your overall health and preferences.
• Surgery options include Breast-Conserving Surgery (BCS) or Lumpectomy (removal of the tumor and a small margin of healthy tissue, usually followed by radiation therapy) and Mastectomy (removal of the entire breast, which can be skin-sparing, nipple-sparing, or total).
• Lymph node surgery includes Sentinel Lymph Node Biopsy (SLNB) to remove the first few lymph nodes where cancer is likely to spread, and Axillary Lymph Node Dissection (ALND) if cancer has spread to more lymph nodes.
• Radiation therapy uses high-energy rays to destroy cancer cells, often used after lumpectomy or mastectomy, and for palliative care.
• Chemotherapy uses powerful drugs to kill cancer cells, given before surgery (neoadjuvant) to shrink tumors or after surgery (adjuvant) to eliminate remaining cancer cells.
• Hormone (endocrine) therapy is used for ER-positive and/or PR-positive cancers, including Selective Estrogen Receptor Modulators (SERMs) like Tamoxifen, Aromatase Inhibitors (AIs) like Anastrozole (for postmenopausal women), and Ovarian Function Suppression (for premenopausal women).
• Targeted therapy drugs target specific characteristics of cancer cells, such as Anti-HER2 Therapy (e.g., Trastuzumab) for HER2-positive cancers, CDK4/6 Inhibitors (e.g., Palbociclib) for advanced ER-positive, HER2-negative cancer, and PARP Inhibitors (e.g., Olaparib) for patients with germline BRCA mutations.
• Immunotherapy, such as Immune Checkpoint Inhibitors (e.g., Pembrolizumab), is used in combination with chemotherapy for certain types of early-stage and advanced triple-negative breast cancer (TNBC).
• After treatment, regular follow-up appointments with physical exams and annual surveillance mammography are recommended. Routine recommendations for other imaging or blood tumor markers are generally not made for asymptomatic patients after treatment for early-stage disease.
• Referral to a multidisciplinary breast cancer team, medical oncologist, radiation oncologist, plastic surgeon, genetic counseling, fertility specialists, and physical therapy/lymphedema specialists may be indicated.

Frequently Asked Questions