Although breast cancer is often referred to as one disease, there are actually many different types of breast cancer.
All breast cancers start in the breast, so they are alike in some ways, but differ in others. They can be non-invasive or invasive. Tumor cells can vary in location (ducts or lobules) and how they look under a microscope. These differences often affect prognosis.
Tumor characteristics, such as hormone receptor status and HER2 status, can also affect prognosis.
Learn more about these tumor characteristics and other factors that affect prognosis.
Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer. In situ means "in place." With DCIS, the abnormal cells are contained in the milk ducts of the breast and have not spread to nearby breast tissue.
Although DCIS is non-invasive, without treatment, the abnormal cells could develop into invasive breast cancer over time. So, you may also hear the terms “pre-invasive” or “pre-cancerous” to describe DCIS.
Learn more about DCIS.
Learn more about breast anatomy.
Invasive breast cancer has spread from the original site (either the milk ducts or the lobules) into the nearby breast tissue, and possibly to the lymph nodes and/or other parts of the body. For this reason, invasive breast cancers have a poorer prognosis than DCIS.
Using a microscope to look at the tissue removed during a biopsy, a pathologist can determine whether a tumor is DCIS or invasive breast cancer.
Figure 4.6 lists the types of invasive breast cancer.
The most common type is invasive ductal carcinoma (also called infiltrating ductal carcinoma and less commonly, invasive carcinoma of no special type or invasive carcinoma not otherwise specified). Invasive ductal carcinoma accounts for about 50 to 75 percent of all breast cancers .
Invasive lobular carcinoma is the next most common type and accounts for about five to 15 percent of cases .
Tubular carcinoma and mucinous (colloid) carcinoma are less common types of invasive breast cancer . They tend to have a good prognosis .
Though they are not specific types of tumors, some special forms of breast cancer are discussed below. These include:
Inflammatory breast cancer (IBC) is a rare, but aggressive form of locally advanced breast cancer. It is called inflammatory breast cancer because its main symptoms are swelling (inflammation) and redness of the breast.
About one to five percent of breast cancers are IBC [15-16].
IBC tumors are often estrogen receptor-negative and HER2-positive. Because IBC is aggressive, most women with IBC have positive lymph nodes and about 30 percent have metastasis when they are diagnosed .
The median age at diagnosis of IBC is slightly younger than the age at diagnosis of other breast cancers [15-16].
African-American women may be somewhat more likely than white women to be diagnosed with IBC [15-16]. Women who are obese may also be more likely than other women to be diagnosed with IBC [15-17].
Although some viral e-mails suggest that IBC is a new form of breast cancer, it was first identified in the 1800’s .
Warning signs of IBC include (see images) [15-16]:
Although sometimes a lump can be felt, it is less common with IBC than with other breast cancers
If you notice any of these changes, see your health care provider.
With other breast cancers, symptoms may not occur for years. However, with IBC, symptoms tend to arise within weeks or months.
Because of the frequent lack of a breast lump and symptoms such as redness and swelling, IBC may first be mistaken for an infection. IBC is often diagnosed clinically with a tissue biopsy after symptoms do not improve with a course of antibiotics.
Tell your health care provider if you have symptoms that last longer than a week after starting antibiotics. Don’t be afraid to get a second opinion (learn more).
Routine mammography can miss IBC because of its rapid onset. IBC can also be hard to see on a mammogram because it is often spread throughout the breast or may only show up as a sign of inflammation (such as skin thickening) . In some cases, skin changes (listed above) or a lump (if one is present) may be noted during a clinical breast exam.
With treatment, 54 to 62 percent of those with IBC will live at least five years after diagnosis and about 41 to 47 percent will have no signs of breast cancer 10 years after diagnosis [18-22].
Although these rates are not as high as for other breast cancers, new treatments continue to improve survival.
Learn about treatment for IBC.
Paget disease of the breast (Paget disease of the nipple) is a rare cancer in the skin of the nipple or in the skin closely surrounding the nipple.
It is usually, but not always, found with an underlying breast cancer. In these cases, the tumor grows from underneath the nipple and breaks out onto the skin surface of the nipple. Paget disease of the breast can be found with invasive breast cancer or DCIS .
About one to three percent of breast cancers are Paget disease of the breast . Although Paget disease of the breast is rare in both women and men, it occurs more often in men .
Warning signs include itching, burning, redness and scaling of the skin on the nipple and areola. There may also be a bloody discharge from the nipple, and the nipple may appear flattened against the breast .
See images of warning signs of breast cancer, including signs of Paget disease of the breast.
Paget disease of the breast can be diagnosed from a biopsy of the nipple skin and the tissue just below the skin (called a skin biopsy or a punch biopsy).
Paget disease of the breast may also be found when an underlying breast cancer is diagnosed.
Treatment and prognosis depend on the underlying cancer .
Metaplastic breast cancer is rare, accounting for fewer than five percent of all invasive breast cancers .
Compared to more common types of breast cancer, metaplastic tumors tend to be larger, have a higher tumor grade and be estrogen receptor-negative, progesterone receptor-negative and HER2 receptor-negative (often called triple negative) [14,25-26].
Under a microscope, metaplastic tumor cells can look very different from the tumor cells of more common breast cancers. So, these cancers can be hard to diagnose and are often confused with other uncommon breast tumors or tumors from other parts of the body. It is best to have the pathology slides sent out for review to confirm the diagnosis.
You can request that your health care provider send the slides out for review or you may wish to get a second opinion for confirmation.
Learn more about breast pathology practices.
Learn more about getting a second opinion.
Most cancers that occur in the breast are breast cancers (breast carcinomas). In rare cases, other types of cancer such as lymphomas (cancer of the lymph system) and sarcomas (cancer of the soft tissues) can occur in the breast. Rarely, cancers from other sites can metastasize (spread) to the breast and mimic breast cancers.
Other types of tumors in the breast can be benign (not cancer) or malignant (cancerous). Because these cancers are not carcinomas, they are treated differently and have different risk profiles than breast cancer.
For more information on other cancers that can occur in the breast, such as lymphomas and benign and malignant phyllodes tumors, visit the National Cancer Institute's website.
Facts for Life: Types of Breast Cancer Tumors
Facts for Life: Breast Cancer Prognosis
Breast Cancer 101 (Interactive Multimedia) - Tumors
Breast Cancer 101 - Tumor Size and Spread
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