Breast cancer is a disease in which malignant (cancerous) cells form in the breast tissue. The breast is made up of lobes and ducts. Each side of the breast consists of 15 to 20 lobes. Each lobe is divided into several lobules. Each lobe is divided into several lobules, which in turn consist of many milk-producing vesicles. The lobes, lobules, and follicles are connected by ducts.
Each side of the mammary gland also contains blood vessels and lymphatic vessels. The lymphatic ducts contain an almost colorless fluid called lymph fluid. The lymphatic vessels are responsible for transporting lymphatic fluid between the lymph nodes. Lymph nodes are small, bean-like structures located throughout the body that filter material from the lymph fluid and help fight infection and disease. Clusters of lymph nodes exist in the armpit (under the arm) near the breast, on the collarbone, and in the chest wall.
The most common type of breast cancer is ductal carcinoma, which starts in the ductal cells. Breast cancers that start in the lobes or lobules of the breast are called lobular cancers and are more likely to occur bilaterally than other types of breast cancer. Inflammatory breast cancer is a rare type of breast cancer in which the breast becomes warm, red and swollen.
Family history and its other factors that increase the risk of breast cancer
Any factor that increases the chance of getting the disease is called a risk factor. The presence of a risk factor does not mean you will get cancer; the absence of a risk factor does not mean you will not get cancer. If you think you are at risk for breast cancer, tell your doctor.
Risk factors for breast cancer include the following:
- A personal history of invasive breast cancer, ductal carcinoma in situ (DCIS), or lobular carcinoma in situ (LCIS).
- Personal history of benign (non-cancerous) breast disease.
- Personal history of benign (non-cancerous) breast disease.
- Family history of breast cancer in a first-degree relative (mother, daughter, or sister).
- Genetic changes in the BRCA1 and BRCA2 genes and other genes that can increase the risk of breast cancer.
- Mammograms showing dense breast tissue.
- Exposure of breast tissue to estrogen produced by the body.
- Early age of menarche.
- Older age at first childbirth or never had children.
- Later age of menopause.
- Taking some hormones, such as estrogen combined with progestin, because of the symptoms of menopause.
- Has received radiation therapy to the breast/chest.
- Drinking alcohol.
- Drinking alcohol.
- Obesity.
Advancing age is a major risk factor for most cancers. As you get older, the chance of developing cancer increases.
Breast cancer is sometimes the result of a genetic mutation that is inherited.
The genes in a cell carry genetic information received from their parents. Hereditary breast cancer accounts for about 5% to 10% of all breast cancers. Some of the mutations associated with breast cancer are more common in specific ethnic groups.
Women who carry mutations in specific genes, such as BRCA1 or BRCA2 mutations, have an increased risk of breast cancer. These women also have an increased risk of ovarian cancer and may also have an increased risk of other cancers. Men who carry genes with mutations associated with breast cancer also have an increased risk of developing breast cancer.
There are tests that can find mutated genes. Sometimes these genetic tests are performed for family members who are at high risk of developing cancer.
Factors such as medications can reduce the risk of breast cancer
Any factor that reduces the chance of getting a certain disease is called a protective factor.
Protective factors for breast cancer include the following:
- Taking the following medications.
- Hormone therapy with estrogen after hysterectomy.
- selective estrogen receptor modulator (SERM)
- Aromatase inhibitors.
- Reduces exposure of breast tissue to human estrogens.
- Earlier pregnancy.
- Lactation.
- Exercising fully.
- Undergo any of the following procedures.
- Prophylactic mastectomy.
- Prophylactic oophorectomy.
- Ovarian debulking.
Symptoms of developing breast cancer include the presence of a lump or changes in the breast. These symptoms and other signs may be caused by breast cancer or other diseases. Contact your doctor if you have any of the following symptoms:
- A lump or thickening in or near the breast or in the armpit.
- A change in the size or shape of the breast.
- Depression or wrinkling of the skin of the breast.
- The nipple sinks inward into the mammary gland.
- The nipple is overflowing with fluid (but not milk), especially bloody fluid.
- Scaly, red, or swollen skin on the breast, nipple, or areola (the darkened area of skin around the nipple).
- A shallow, orange peel-like depression in the breast called the “orange peel sign”.
Tests to detect and diagnose breast cancer
Contact your doctor if you notice any changes in your breast. The following tests may be used:
- Health examination and medical history: A physical examination to check general health status, including checking for signs of disease, such as lumps or any abnormalities. Information should also be taken about the patient’s health habits, previous illnesses, and medical history of previous treatment.
- Clinical breast exam (CBE): An examination of the breast by a doctor or other health professional. The doctor will carefully touch the breast and underarm area to look for lumps or abnormalities.
- Mammogram: An x-ray of the breast.
- Ultrasound: High-energy sound waves (ultrasound) are projected onto internal tissues or organs to form echoes. From these echoes, an image of the body’s tissues is produced called a sonogram. Such images can be printed out for later observation.
- Magnetic resonance imaging (MRI): A series of detailed images of the bilateral breast are produced using magnets, radio waves, and a computer, in a sequence also known as nuclear magnetic resonance imaging (NMRI).
- Blood chemistry test: A blood sample is examined to measure the amount of a specific substance that is released into the blood by the body’s organs and tissues. Abnormal levels of a substance (higher or lower than normal) may be a sign of disease.
- Biopsy: Removal of cells or tissue so that a pathologist can look at them under a microscope to check for signs of cancer. If a mass is found in the breast, it will need to be biopsied. There are four types of biopsies used to check for breast cancer.
- Excisional biopsy: The entire mass of tissue is removed for examination.
- Excisional biopsy: A portion of the mass or tissue sample is cut for examination.
- Hollow-core needle biopsy: A coarse needle is used to obtain tissue for examination.
- Fine needle aspiration (FNA) biopsy: tissue or fluid is obtained using a fine needle for examination.
If cancer is found, further tests are needed to study the tumor cells. Decisions about the best treatment are based on the results of these tests. These tests can provide the following information:
- The growth rate of the tumor.
- The likelihood of the tumor spreading along the body.
- The extent to which specific treatments may play a role.
- The likelihood of cancer recurrence.
Examinations include the following:
- Estrogen and progesterone receptor testing: A test that measures the number of estrogen and progesterone receptors in the cancer tissue. If there are more estrogen and progesterone receptors than normal, the cancer is estrogen and/or progesterone receptor positive. This type of breast cancer will grow faster. The results of this test indicate whether treatment given to antagonize estrogen and progesterone can stop tumor growth.
- Human epidermal growth factor receptor-2 (HER-2) test: Determines how many HER-2 genes are present in a tissue sample and how much HER-2 protein is produced. If it contains higher than normal levels of the HER-2 gene or HER-2 protein, the cancer is said to be HER-2-positive. This type of breast cancer grows more quickly and spreads more easily to other parts of the body. This type of breast cancer can be treated with drugs that target HER-2/neu, such as trastuzumab and patuximab.
- Multigene testing: In this type of testing, the activity of multiple genes in a tissue sample is looked at at the same time. These tests may help predict whether the cancer will spread to other parts of the body or recur.
- 21 Genetic testing: This test helps predict whether stage I or II breast cancer that is estrogen receptor positive and lymph node negative will spread to other parts of the body. If there is a higher risk of cancer spreading, chemotherapy may be given to reduce this risk.
- MammaPrint genetic test: This test helps predict whether lymph node-negative stage I or II breast cancer will spread to other parts of the body. If there is a higher risk of the cancer spreading, chemotherapy may be given to reduce this risk.
Based on these tests, breast cancer can be described as:
- Hormone receptor positive (estrogen and/or progesterone receptor positive) or hormone receptor negative (estrogen and/or progesterone receptor negative).
- HER-2 positive or HER-2 negative.
- Triple negative (estrogen receptor, progesterone receptor, and HER-2 negative).
This information helps your doctor determine which treatments are most effective for your cancer.
Specific factors that affect prognosis and treatment choice
Prognosis (chance of getting well) and treatment choices depend on:
- The stage of the cancer (the size of the tumor and whether it is confined to the breast or has spread to the lymph nodes and other parts of the body).
- The type of breast cancer.
- Levels of estrogen receptors and progesterone receptors in the tumor tissue.
- The level of HER-2 in tumor tissue.
- Whether the tumor tissue is triple negative.
- The rate of tumor growth.
- The growth rate of the tumor.
- The likelihood of tumor recurrence.
- The likelihood of tumor recurrence.
- The woman’s age, general health, and menopausal status (whether the menstrual cycle still exists).
- Whether the cancer is newly diagnosed or a recurrence of a previous cancer.