Breast cancer originates from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas; those originating from lobules are known as lobular carcinomas.
Etiology:
Over the course of a lifetime, 1 in 8 women will be diagnosed with breast cancer.
Risk factors you cannot change include:
- Age and gender
- Family history of breast cancer
- Mutation
- Menstrual cycle
- Alcohol use
- Childbirth
- Diethylstilbestrol (DES)
- Hormone replacement therapy (HRT)
- Radiation
Signs & Symptoms:
Early breast cancer usually does not cause symptoms. As the cancer grows, symptoms may include:
- A breast lump or lump in the armpit that is hard, has uneven edges, and usually painless.
- Change in the size, shape, or feel of the breast or nipple
- Fluid discharge from nipple
Radiological Modalities:
- Mammography
- Breast Ultrasound
- Breast CT
- Biopsy (FNA)
- PET Scan
- MRI
Staging:
Stage 0 is used to describe non-invasive breast cancers, such as DCIS and LCIS. In stage 0, there is no evidence of cancer cells or non-cancerous abnormal cells breaking out of the part of the breast in which they started, or of getting through to or invading neighboring normal tissue.
Stage I describes invasive breast cancer (cancer cells are breaking through to or invading neighboring normal tissue) in which:
- the tumor measures up to 2 centimeters, AND
- no lymph nodes are involved
Stage II
Stage IIA
- no tumor can be found in the breast, but cancer cells are found in the axillary lymph nodes (the lymph nodes under the arm), OR
- the tumor measures 2 centimeters or less and has spread to the axillary lymph nodes, OR
- the tumor is larger than 2 centimeters but not larger than 5 centimeters and has not spread to the axillary lymph nodes
Stage IIB
- the tumor is larger than 2 but no larger than 5 centimeters and has spread to the axillary lymph nodes, OR
- the tumor is larger than 5 centimeters but has not spread to the axillary lymph nodes
Stage III
Stage IIIA
- no tumor is found in the breast. Cancer is found in axillary lymph nodes that are clumped together or sticking to other structures, or cancer may have spread to lymph nodes near the breastbone, OR
- the tumor is 5 centimeters or smaller and has spread to axillary lymph nodes that are clumped together or sticking to other structures, OR
- the tumor is larger than 5 centimeters and has spread to axillary lymph nodes that are clumped together or sticking to other structures
Stage IIIB
- the tumor may be any size and has spread to the chest wall and/or skin of the breast AND
- may have spread to axillary lymph nodes that are clumped together or sticking to other structures, or cancer may have spread to lymph nodes near the breastbone
- Inflammatory breast cancer is considered at least stage IIIB.
Stage IIIC
- there may be no sign of cancer in the breast or, if there is a tumor, it may be any size and may have spread to the chest wall and/or the skin of the breast, AND
- the cancer has spread to lymph nodes above or below the collarbone, AND
- the cancer may have spread to axillary lymph nodes or to lymph nodes near the breastbone
Stage IV: The cancer has spread to other organs of the body — usually the lungs, liver, bone, or brain
Treatment:
- Stage 1 cancers (and DCIS) have an excellent prognosis and are generally treated with lumpectomy and sometimes radiation. HER2+ cancers should be treated with the trastuzumab regime.Chemotherapy is uncommon for other types of stage 1 cancers.
- Stage 2 and 3 cancers with a progressively poorer prognosis and greater risk of recurrence are generally treated with surgery (lumpectomy or mastectomy with or without lymph node removal), chemotherapy (plus trastuzumab for HER2+ cancers) and sometimes radiation (particularly following large cancers, multiple positive nodes or lumpectomy).
- Stage 4, metastatic cancer, (i.e. spread to distant sites) has poor prognosis and is managed by various combination of all treatments from surgery, radiation, chemotherapy and targeted therapies. 10 year survival rate is 5% without treatment and 10% with optimal treatment.