Breast MRI System for Breast Cancer - Medical / Health Care - Clinical Services
Cancer is a group of diseases in which normal cells change and grow out of control. In breast cancer, the cancerous cells are usually cells of the lobules and ducts (ie, the glands that produce milk and the channels that carry milk to the nipple). Keep in mind that cancer, or carcinoma, of the breast can be broadly divided into two categories :
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non-invasive or in situ carcinoma: cancer cells are confined to the areas where they originated, either the ducts (ductal carcinoma in situ; DCIS) or lobules (lobular carcinoma in situ; LCIS)
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invasive carcinoma: cancers that started in ducts or lobules but have spread beyond them to invade surrounding tissues of the breast
To learn more about breast cancer click the links below.
Major Types and Pathology of Breast Cancer
Breast cancer is broadly divided into carcinoma in situ and invasive breast cancers. Carcinoma in situ, in turn, is categorized according to whether it is confined to the lobules or ducts :
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Lobular carcinoma in situ (LCIS): Although LCIS probably does not develop into invasive cancer, women with LCIS have a higher risk of developing invasive cancer in either breast.
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Ductal carcinoma in situ (DCIS): DCIS is the most common type of noninvasive breast cancer. If not treated, it may grow and become invasive cancer. DCIS can usually be cured with surgery and sometimes radiation. Invasive breast cancers are cancers that have spread beyond the ducts or lobules. Invasive cancers are categorized based on how they look under the microscope and how they compare to normal cells. This description, called the cancer grade, helps predict the patient’s outcome, or prognosis. Some major types of invasive breast cancer are summarized below
Types of Invasive Breast Cancer
Invasive ductal carcinoma (IDC)
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Accounts for about 80% of invasive breast cancers
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Begins in a duct of the breast, breaks through the duct wall and spreads into fatty tissue; cancer cells then spread into lymphatic channels or blood vessels and spread to other parts of the body
Invasive lobular carcinoma (ILC)
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Accounts for 10% to 15% of invasive breast cancers
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Begins in a lobule of the breast, breaks through lobe boundaries and, similar to IDC, spreads to other parts of the body
Mixed tumors
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Contains a variety of cell types (eg, mixture of IDC and ILC); usually treated as if it were an invasive ductal cancer
Medullary cancer
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Accounts for 5% of invasive breast cancers
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A form of invasive ductal cancer with a defined boundary between the tumor cells and normal breast tissue; difficult to distinguish from normal IDC; most oncologists believe it should be treated as IDC
Metaplastic tumors
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Very rare form of IDC; tumors include cells not normally found in the breast; treated similarly to IDC
Inflammatory breast cancer (IBC)
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Accounts for 1% to 3% of all breast cancers
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Form of cancer in which cancer cells have spread to lymph channels in the skin of the breast, giving the skin a red, swollen, orange-peel appearance; breast may also become larger, firmer, tender, or itchy; IBC has a greater chance of spreading and worse outlook than typical IDC or ILC
Colloid carcinoma
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Rare type of IDC; also called mucinous carcinoma, formed from mucusproducing cancer cells; has a better outlook and lower chance of metastasis than IDC or ILC cancers of the same size
Tubular carcinoma
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Accounts for about 2% of all invasive breast cancers
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Form of IDC, but less likely to spread than ILC or IDC cancers of the same size
Apart from skin cancer, breast cancer is the most common cancer in women. In 2009, about 192,370 new cases of invasive breast cancer and 62,280 new cases of in situ breast cancer are expected to occur among U.S. women, for a total of about 254,650 new cases overall. The incidence of breast cancer and death rates generally increase with age. In fact, during 2000-2004, 95% of new cases of breast cancer, and 97% of deaths from breast cancer, occurred in women aged 40 and older. Age differences are also clearly seen in incidence rates: Women 20 to 24 years have the lowest rate of breast cancer (1.4 cases per 100,000), while women 75 to 79 years having the highest rate (465 cases per 100,000). White women have a higher incidence of breast cancer than African American women after age 40. However, African American women are more likely to die from breast cancer at every age. Women of other racial and ethnic groups have a lower incidence and death rates than white and African American women.
Other key facts and trends include :
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In 2005, about 2.4 million women with a history of breast cancer were alive, most of whom were cancer-free
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The incidence of breast cancer has decreased by 2.2% per year from 1999 to 2005. According to the American Cancer Society, this decline is probably due to an increase in mammography screening, as well as decreased used of hormone replacement therapy (HRT), following the publication of the results of the Women’s Health Initiative randomized trial in 2002.
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The importance of early detection and diagnosis is seen in the fact that survival rates five years after diagnosis are markedly higher among women diagnosed at an earlier stage.
Risk factors for breast cancer
Like other diseases, risk factors for breast cancer can be divided into those that are modifiable (those that a person may change through behavioral modification) and non-modifiable (those that a person cannot normally change).
Below are a list of risk factors according to the American Cancer Society.
Non-modifiable Risk Factors include:Gender
A major risk factor for developing breast cancer is simply being a woman. Men can develop breast cancer (approximately 1,910 cases of male breast cancer are expected in 2009), but the disease is about 100 times more common among women.
Aging
The risk of developing breast cancer increases as a woman ages. A woman’s overall lifetime risk of developing breast cancer is about 12% (1 in 8).
Genetic risk factors
About 5% to 10% of breast cancer cases are thought to be hereditary, resulting directly from gene changes (called mutations) inherited from a parent. There are several gene mutations that have been associated with an increased breast cancer risk.
BRCA1 and BRCA2:
In a person without this gene mutation, these genes act as tumor suppressors, producing proteins meant to prevent abnormal cell growth. When the gene is mutated, they are no longer able to function as tumor suppressors, so breast cancer is more likely to develop. Although mutations to these genes are relatively rare (less than 1% of the population), they can significantly increase risk if present. Women with an inherited BRCA1 or BRCA2 mutation have up to an 80% chance of developing breast cancer during their lifetime, and when they do it is often at a younger age than in women who are not born with one of these gene mutations. Women with these inherited mutations also have an increased risk for developing ovarian cancer.
Changes in other genes: Other gene changes might also lead to inherited breast cancers. These genes do not pass on the same level of breast cancer risk as the BRCA genes, and do not frequently cause familial or inherited breast cancer.
