Breast Cancer occurs when cancerous cells grow out of control within breast tissue. Although all of the causes of breast cancer are not known, it is known that cancerous cells within breasts begin with changes in the DNA of breast cells (Mayo Clinic, 2025). These cells may join together to form a tumor which can not only grow in size, but also travel to and invade other tissues in the body (metastisize) (Mayo Clinic, 2025). Eighty percent of breast cancer cases metastisize to other parts of the body (Cleveland Clinic, 2025). Cancers metastisize through blood and lymphatic systems. As part of the immune system, the lymphatic system is compromised of lymph nodes, ducts, vessels and organs. Together, the parts of the lymphatic system remove lymph from throughout the body and drain it into the blood system. The lymphatic system drains lymph from breast tissue through:
- Auxillary Lymph Nodes - Lymph nodes under the arm.
- Internal Mammary Lymph Nodes - Lymph nodes in the chest under the breastbone.
- Supraclavicular Lymph Nodes - Lymph nodes above the collar bone.
- Infraclavicular Lymph Nodes - Lymph nodes below the collar bone (ACA, 2021).
- Lobules - these are the glands where breast milk is produced.
- Ducts - these are the canals that connect lobules to the nipple and carry breast milk as it is produced.
- Invasive Ductal Carcinoma (IDL)
- Ductal Carcinoma In Situ
- Nipples - location where ducts coalesce into larger ducts in a way that breast milk can leave the breast.
- Areola - the daarker thicker skin that surrounds the nipple.
- Stroma - fat and connective tissue that surround the ducts and lobules in order for them to stay in place.
- Blood Vessels and Lymph Vessels - carry blood and lymph to and from breast tissues.
- Angiosarcoma (ACA, 2021)(Cleveland Clinic, 2025)
- ER positive (ER+): have estrogen receptors.
- PR positive (PR+): have progesterone receptors.
- HR positive (HR+): have estrogen and progesterone receptors.
- HR negative (HR-): have no estrogen or progesterone receptors (Cleveland Clinc, 2025).
- New lump near or in breast or armpit.
- Changes in breast size and shape.
- Puckering or dimples in skin.
- Nipple turning inward.
- Nipple discharge.
- Skin of nipple becoming scaly, red or swolen.
- Breast pain.
- Color changes of breast skin (Mayo Clinic, 2025)(Cleveland Clinic, 2025)(Medline Plus, 2025).
- Older age
- Gender
- History of Breast Cancer
- BRCA gene and other genetic mutations
- Dense breast tissue
- Menarche at an early age
- Older age at first childbirth
- Having never giving birth
- Menopause at older age
- Hormone Replacement Therapy
- Radiation Therapy to breast or chest area
- Obesity
- Alcohol
- Smoking (Mayo Clinic, 2025)(Cleveland Clinic, 2025)(Medline Plus, 2025)
- Speak with health clinician about screening
- Do breast exams
- Moderation of drinking alcohol
- Regular exercise
- Limit menopausal hormone therapy
- Maintain healthy weight
- Eat healthy diet
- Genetic screening
- Preventative medicines
- Preventative surgery (ACA, 2021)(Medline Plus, 2025)(Mayo Clinic, 2025)(Cleveland Clinic, 2025)
- Medical history
- Breast exam
- Mammogram - x-ray of breast tissue
- Breast ultrasound - pictures are created using sound waves
- Breast MRI - pictures created using magnetic field and radio waves
- Biopsy - tissue sample removed for testing to see if cells are cancerous
- Staging of the Breast Cancer through:
- Blood tests
- Bone scan
- CT scan
- MRI
- PET scan
- Immunohistochemistry - looks for hormone receptors
- Genetic testing
- HER2 test - tests for the HER2 protein which is involved in cell growth
- Chemotherapy
- Radiation therapy
- Hormone Therapy - blocks hormones from attaching to cancer cells
- Immunotherapy
- Surgery
- Mastectomy
- Lumpectomy
- Breast reconstruction (Cleveland Clinic, 2025)(Medline Plus, 2025).