Description
Breast cancer is a malignant tumor formed from abnormal cell division and growth in breast cells.
Symptoms of Disease
- Lump or mass
- Skin irritation or dimpling
- Redness or scaliness of the nipple or breast skin
- Swelling
- Nipple pain or retraction
- Nipple discharge (other than breast milk)
There are two main categories of breast cancer:
- Carcinoma in situ (CIS): abnormal cells are isolated to a specific region of the breast
- In situ: Latin for "in place"
- Early stage of cancer
- Cancer confined to the lobules and the ducts
- Invasive: cancer cells have moved from isolated region of breast to invade other breast tissue
- Once cancer invades other regions of the breast, it can spread to other regions of the body (metastasis)
How Common is Breast Cancer?
- Breast cancer is the one of the most commonly diagnosed cancers in women (second only to nonmelanoma skin cancers).
- In 2008, researchers estimate that approximately 182,460 new cases of invasive breast cancer and 67,770 cases of CIS will be diagnosed in women in the United States; 1,990 cases of invasive breast cancer will be diagnosed in men.
- Breast cancer is the second leading cause of cancer-related death in women (exceeded only by lung cancer).
- This year, about 40,480 women and 450 men will die from breast cancer in the United States.
- Today, there are more than 2.4 million breast cancer survivors living in the United States.
Disparities
- Although Caucasian women have the highest incidence of breast cancer, they have the lowest rates of mortality, compared to other racial/ethnic groups
- African American women are less likely to be diagnosed with breast cancer, compared to other racial/ethnic groups, yet they are more likely to be diagnosed with late-stage breast cancer and most likely to die from breast cancer
Types of Breast Cancer
Breast cancer tumors can form in any breast cell and develop into in situ and/or invasive cancers. Breast cancers can also arise as mixed tumor types, characterized by a combination of cancerous cell and tumor types.
Because most breast cancers begin in the ducts and lobules, all breast cancers fall under the category of adenocarcinomas, cancers of the glandular tissue of the body.
- In situ cancers:
- Ductal carcinoma in situ (DCIS): non-invasive tumor that is confined to the duct cells, tunnels that allow transportation of milk from the milk-producing glands to the nipple
- Most commonly diagnosed non-invasive breast cancer
- 20 percent of all new cases of breast cancer will be DCIS
- Lobular carcinoma in situ (LCIS): non-invasive tumor isolated to the lobules, the breast glands that produce milk
- While LCIS is non-invasive, patients with LCIS are believed to be at a higher risk for developing other invasive types of breast cancer
- Invasive cancers:
- Invasive (or Infiltrating) ductal carcinoma (IDC): cancerous cells that spread from the ducts, tunnels that allow transportation of milk from the lobules to the nipple, to other regions of breast tissue
- Most commonly diagnosed breast cancer
- 80 percent of all diagnosed invasive carcinomas are IDC
- Invasive (or Infiltrating) lobular carcinoma (ILC): cancer cells that originate in lobules, milk-producing regions of breast, invade surrounding breast tissue
- 10 percent of all diagnosed invasive carcinomas are ILC
- Inflammatory breast cancer (IBC): characterized by cancerous cells that do not form lumps or tumors, but rather cancer cells that interfere with lymphatic system of the breast, causing swelling of the breast
- Early detection of IBC is very difficult
- IBC is the most aggressive of invasive breast cancers
- IBC spreads quickly to the rest of the body
- Less commonly diagnosed types of breast cancer:
- Medullary cancer: invasive cancer with higher rates of diagnosis among women with genetic predisposition for breast cancer (BRCA1 gene mutation)
- Paget disease of the nipple: cancer of the nipple and areola; often appears in combination with other breast cancers
- Angiosarcoma: very rare form of breast cancer, which arises from cancer of blood and lymph vessels
- Metaplastic tumors: variant of invasive ductal carcinoma
- Tubular carcinoma: tube-shape cancer cells; variant of invasive ductal carcinoma
- Mucinous (or colloid) carcinoma: cancer in mucous cells of the breast
- Phyllodes tumor: tumors that develop in the connective tissue of the breast; usually benign but may be malignant
Diagnosis
The discovery of a lump in the breast is typically the first sign of breast cancer. While the presence of a lump can be a sign of a variety of non-cancerous breast diseases, all newly detected masses in the breasts should be reported to medical professionals for further analysis.
In addition to self-breast exams and physician breast exams, annual mammograms (breast x-rays) for women over the age of 40 can help to identify lumps in the breast. Additional imaging techniques may also be used to locate a breast tumor, or evaluate the severity of the mass present.
Additional tests to aid in the detection of breast cancer:
- MRI
- Breast ultrasound
- Ductogram
- Full-field digital mammogram
- Computer aided detection and diagnosis
- Nipple discharge exam
- Ductal lavage and nipple aspiration
Typically, once a mammogram or other imaging techniques reveal a lump in the breast, cells from the tumor are removed and analyzed under microscope to determine whether or not the lump is cancerous. The removal and analysis of tumor cells is called a biopsy.
There are two types of biopsies:
- Needle: hollow needle captures cells of tumor for analysis
- Surgical (excisional): surgery removes tumor entirely or partially to test and evaluate cells
Usually, a needle biopsy is preferred for diagnosis. A surgical biopsy is performed for rare patients for whom needle biopsy is not possible or is inconclusive.
If biopsy indicates the presence of cancer:
- Additional imaging tests such as CT, MRI, and PET will help to evaluate whether cancer has spread to other regions of the body
- Doctors will assign a cancer type and category based upon the size of tumor, how quickly cancer cells are growing, and whether or not cells have spread into other breast tissues or other regions of the body.
- Cancer cells will be tested for presence of estrogen and progesterone hormone receptors (region on outside of cell where receptors bind, initiating intracellular activity)
- In many types of breast cancer, estrogen leads to increased growth of cancer
- Cancer cells that have hormone receptors, or hormone-positive cells, often respond to hormone therapy (drugs that block receptors) for cancer treatment
- Cancer cells will be tested for presence of growth-promoting protein called HER2/neu
- Cancers with increased HER2/neu, called "HER2/neu-positive cancers," have numerous HER2/neu proteins on surface of cancer cells; tend to grow and spread rapidly
- Patients under 50 with breast cancer and/or with a family history of breast cancer may also receive genetic testing to identify whether or not they have BRCA1 or BRCA 2 mutation
Breast cancer patients with BRCA mutations are at increased risk for another breast cancer and for ovarian cancer.
Treatment Options
The treatment of breast cancer is strongly influenced by the location, stage, characteristics of cancer cells (ex. hormone-positive, HER2/neu-positive), and breast cancer history.
Surgery
Typically, surgery provides the first line of defense against breast cancer. Based upon the type of cancer, surgery may be more or less invasive, and combined with other therapy.
- Lumpectomy (breast conservation surgery): removal of breast cancer lump and surrounding tissue
- Mastectomy: removal of entire breast; women who undergo mastectomy can opt to undergo immediate or delayed breast reconstruction
- Axillary (Underarm) lymph node dissection: because breast cancer can spread to the lymph nodes located in the underarm, lymph nodes from this region may be surgically removed and analyzed
- Frequently combined with lumpectomy or mastectomy
- Results of dissection often influence cancer treatment
- Sentinel lymph node biopsy: evaluates presence of cancer in lymph nodes with a minor surgical procedure
- If biopsy reveals cancer in the lymph node, axillary dissection will be performed
Chemotherapy
Chemotherapy, or anti-cancer drug treatment, attempts to halt uncontrolled cell division of cancer by destroying all rapidly dividing cells. Different chemotherapy drugs will be prescribed based upon the type and stage of breast cancer.
- Although chemotherapy techniques wipe out cancer cells, many normal, rapidly dividing healthy cells are also killed by these treatments. The death of healthy cells causes undesirable side effects for cancer patients such as hair loss, mouth sores, nausea and more. To decrease harmful side effects of chemotherapy, researchers are working to develop ways to tailor anti-cancer drugs to destroy cancer cells alone or interfere with the processes that promote cancer growth.
While doctors may prescribe different types of anti-cancer drugs, chemotherapy can be used to:
- Reduce the size of the breast tumor prior to surgery so that breast-conserving surgery can be performed in place of full removal of breast
- Reduce the risk of recurring breast cancer following removal of breast tumor
- Treat breast cancer that has metastasized, or spread, to other regions of the body
Anti-cancer drugs can be taken by mouth or vein. Commonly prescribed chemotherapy drugs for breast cancers are:
- Cyclophosphamide (Cytoxan®)
- Doxorubicin (Adriamycin)
- Epirubicin (Ellence®)
- Fluorouracil (5FU)
- Methotrexate (Matrex)
- Paclitaxel (Taxol®)
- Docetaxel (Taxotere®)
- Capecitabine (Xeloda®)
- Vinorelbine (Navelbine®)
- Gemcitabine (Gemzar®)
- Ixabepilone (Ixempra®)
Additional drugs used in combination with chemotherapy:
- Hormone therapy: drugs that work to lower the amount of estrogen in the body and block estrogen from promoting growth of hormone-positive breast cancers; most of hormone therapy drugs are limited to post-menopausal women
- Drugs that block estrogen receptor:
- Tamoxifen (Nolvadex®): only approved estrogen-blocking drug for premenopausal women
- Toremifene (Fareston®)
- Drugs that inhibit the production of estrogen:
- Fulvestrant (Faslodex®): destroys estrogen receptor
- Aromatase inhibitors: block enzyme needed to produce estrogen in postmenopausal women; cannot stop estrogen production in premenopausal women
- HER2/neu targeted therapy: drugs that work to block growth of HER2/neu cancer cells by attaching to growth-promoting protein, HER2/neu
- Trastuzumab (Herceptin®): drug that binds to HER2/neu, disabling the protein from promoting the growth of HER2/neu tumors; signals body to attack HER2/neu-positive cancers
- Lapatinib (Tykerb®): typically prescribed if Trastuzumab fails in cancer patients
- Angiogenesis inhibitors: drugs that prevent tumors from accessing blood vessels, shutting tumors off from accessing nutrients and oxygen
- Bevacizumab (Avastin®): blocks vascular endothelial growth factors (VEGF), a protein that helps tumors to build blood vessels
Radiation
Radiation therapy fights cancer by damaging cancer cells with a powerful blast of energy. While researchers direct radiation at specific regions of cancer cells, they cannot be fully isolated and radiation often kills normal, healthy cells of the body. New radiation techniques are better able to avoid damaging normal tissue in treating brain cancer.
- Radiation therapy is used for cancerous cells that remain after surgery to remove breast cancer
- External beam radiation: radiation energy directed from outside source aimed at tumor region; entire breast and surrounding tissue are exposed to external radiation; treatment typically lasts five to six weeks
- Partial breast irradiation: accelerated radiation therapy directed at region where tumor was located for four to five days
- Brachytherapy: internal radiation from source planted in breast tissue near cancer; used in combination with external radiation
Minimizing Risk/Prevention
No one knows what causes breast cancer or who will develop it, and there is no proven means of prevention or cure. What scientists can identify are characteristics held in common by women who develop breast cancer. Some of these characteristics are listed below:
- Age
- Family history of breast cancer - including inheriting a mutation in one of the two breast-cancer related genes, BRCA-1 or BRCA-2
- Carcinoma in situ
- Early onset of menses or late age at menopause; as well as some personal choices like recent use of oral contraceptives
- Never having children or having children after age 30
- Obesity after menopause
- Use of combined estrogen and progesterone hormone replacement therapy.
While there is no way to avoid breast cancer, lifestyle choices may decrease the risk of developing breast cancer. Experts strongly advise maintaining healthy eating habits and a healthy body weight, limiting alcohol consumption, exercising regularly, and, if possible, breast-feeding infants.
New Scientific Developments
Scientists continue to work hard to better understand the causes of breast cancers and ways to improve methods of diagnosis, prognosis and treatments.
Scientists continue to track genetic mutations and other biomarkers that increase one's risk of developing breast cancer. Recently, researchers discovered postmenopausal women with four mutations of the FGFR2 gene had an increased risk of breast cancer. Additionally, women with BRIP1 gene mutations are two times more likely to develop breast cancer than those without mutation.
New evidence suggests that using breast cancer history of female family members to predict breast cancer risk may be potentially harmful to women from small families. In a recent survey, researchers discovered women with less family from which to draw breast cancer history were at a higher risk of carrying the BRCA gene mutation - a mutation that increases chances of developing breast cancer - than others with larger families. Researchers suggest women who have been diagnosed with breast cancer under the age of 50 with few female relatives on mother's or father's side be tested for inherited cancer. While only five to 10 percent of all breast cancers are inherited, it is important the BRCA gene mutation breast cancer be identified early and treated aggressively due to the nature of the cancer.
Scientists believe a combination of dieting and exercise helps to keep breast cancer survivors alive longer. While numerous studies report the positive effects of diet and exercise separately on survival rates, a recent study suggests the combination of behaviors provides the greatest protective effect against breast cancer and lowers the risk of death.
Researchers are also working on new treatments for breast cancer by employing latest nanotechnology, immunotherapy and radiation therapy. Currently, breast vaccines, drugs that boost the body's immune system to recognize and mount an attack upon tumor cells, are in clinical trials.
Sources:
American Cancer Society. Cancer Facts & Figures. Atlanta, American Cancer Society, 2008
1-800-ACS-2345
www.cancer.org
Breastcancer.org
610-642-6550
breastcancer.org
Genetic Health
www.genetichealth.com
National Breast Cancer Coalition
1-800-622-2838
www.natlbcc.org
National Cancer Institute
1-800-4-CANCER
www.cancer.gov
Susan G. Komen For the Cure
1-877-GO KOMEN
www.komen.org
Related AACR Press Releases
Hair straightening chemicals not linked to breast cancer risk in African-Americans
May 17, 2007
Cancer Tip: Study Links Breast Cancer Risk to Epigenetic Changes Related to Race, Smoking and Birth Size
April 15, 2007
Gene Profiling Predicts Resistance to Breast Cancer Drug Herceptin
February 20, 2007
Survey Finds Perceived Risk of Recurrence Is Low in African-American Breast Cancer Survivors
February 15, 2007
Active Lifestyle Reduces Risk of Invasive Breast Cancer
February 15, 2007
Selective Marker Found to Indicate Aggressive Form of Breast Cancer
January 15, 2007
Last reviewed: January 26, 2009