Table of ContentsView AllTable of ContentsSymptomsDiagnosisTreatmentCoping
Table of ContentsView All
View All
Table of Contents
Symptoms
Diagnosis
Treatment
Coping
Metaplastic breast cancer (metaplastic carcinoma of the breast) is a very uncommon type of breast cancer. It is a form ofinvasive ductal cancer, meaning that it forms in the milk ducts and then moves into other tissues of the breast. It can be aggressive and fast-growing, and relatively little is known about metaplastic breast cancer’s causes or long-term prognosis.
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Metaplastic breast cancer differs from other types of breast cancer in that it often contains other types of tissue not normally found in the breast, includingsquamouscells (skin) orosseouscells (bone). “Metaplastic” comes from the Greek phrase for “changed in form,” which is why it describes cells that appear to have morphed into those of another part of the body.
This article discusses the symptoms and diagnosis of metaplastic breast cancer. It also covers treatment options and how to cope with a diagnosis.
Term Confusion"Metaplastic" should not be confused with other terms you may hear in relation to breast cancer:“Metastatic” comes from the Greek phrase for “changed in place,'' describing cancer that has spread from its original site to other areas.“Metaplasia” is sometimes used to describe abnormal (though not yet cancerous) findings on a biopsy.
Term Confusion
“Metaplastic” should not be confused with other terms you may hear in relation to breast cancer:“Metastatic” comes from the Greek phrase for “changed in place,'' describing cancer that has spread from its original site to other areas.“Metaplasia” is sometimes used to describe abnormal (though not yet cancerous) findings on a biopsy.
“Metaplastic” should not be confused with other terms you may hear in relation to breast cancer:
Metaplastic Breast Cancer Symptoms
Some people with metaplastic breast cancer have no symptoms at all and are identified through routine screening. For others, the symptoms are essentially the same as for other types of breast cancer.
Symptoms may include:
Nipple Color and Other Changes
Diagnosing Metaplastic Breast Cancer
Tests todiagnose breast cancerare similar no matter what type of cancer is present.
Imaging
Imaging tests come first and may include:
On mammography, metaplastic breast cancer can appear very similar to both ductal carcinoma and benign masses, which can make the diagnosis more challenging.
Breast Cancer
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Breast Biopsy
Any of the imaging tests above may be helpful in learning more about a tumor, but a breast biopsy is needed to determine the exact type of breast cancer and to learn about characteristics of the tumor, such astumor grade(the aggressiveness of the tumor). No two breast cancers are alike—even tumors that are diagnosed as metaplastic breast cancer.
To specifically diagnose metaplastic breast cancer, the breast tissue must bebiopsied, meaning that a bit of tissue is removed from the breast (surgically or with a special needle) and examined under a microscope.If there is any suspicion of a malignancy on an imaging test, a biopsy will be done to confirm whether the area is benign or malignant.
Breast Biopsy: What to Expect
Receptor Testing
As with other types of breast cancer, special tests are performed on biopsy samples to determinereceptor status.
Some tumors areestrogen-receptor (and/or progesterone-receptor) positive, meaning that estrogen binds to the receptors causing the growth of the tumors. Treatments that either block the receptor or reduce the amount of estrogen in the body can limit the growth of the tumor.
HER2 testingcan determine if the tumor is HER2-positive, meaning that the cells have an increased number of HER2 receptors on the surface. Growth factors bind to these receptors causing the growth of the cancer, and medications that block the HER2 receptor can thus interfere with growth. Overall, about one in five breast cancer cases are HER2-positive, but it’s uncertain exactly how common HER2 positivity is in metaplastic breast cancer.
Treating Metaplastic Breast Cancer
Metaplastic breast cancer is less likely to be estrogen-receptor-positive or HER2-positive, which limits treatment options.Tumors tend to respond poorly to chemotherapy, though radiation can be effective. New hope is vested in targeted therapies that may improve survival and give rise to better treatments in the near future.
Can metaplastic breast cancer be cured?Since this type of cancer is so uncommon, the best treatment modalities for it aren’t really known, but it appears that surgery to remove the tumor and radiation therapy are of greatest benefit. The low frequency of this type of tumor also means that a tried-and-true course of action is not readily apparent.
Can metaplastic breast cancer be cured?
Since this type of cancer is so uncommon, the best treatment modalities for it aren’t really known, but it appears that surgery to remove the tumor and radiation therapy are of greatest benefit. The low frequency of this type of tumor also means that a tried-and-true course of action is not readily apparent.
Surgery
Alumpectomyormastectomyis the most definitive treatment. Since metaplastic breast cancers tend to be larger than other types of breast cancer at diagnosis, mastectomy may be recommended.
Breast Cancer Surgery Options
Radiation Therapy
One of the larger studies to date, a 2017 study looking at treatment options, found that adjuvant radiation therapy was as important as surgery and chemotherapy in preventing local and regional recurrences in metaplastic breast cancer.
Radiation Methods for Breast Cancer Treatment
Hormone Therapy
For tumors that are estrogen-receptor and/or progesterone-receptor-positive, hormonal therapy is often used. However, the incidence of hormone receptor-positive disease is lower with metaplastic breast cancer, and the majority of these cancers are hormone-receptor negative.
HER2-Targeted Therapies
HER2-Positive Treatments
Chemotherapy
Many of these cancers are at a higher stage than average for breast cancer at diagnosis, so chemotherapy is often recommended. That said, chemotherapy does not appear to be as effective for metaplastic breast cancer.
mTOR Inhibitors
Treatment options for metaplastic cancers that are estrogen-receptorandHER2-negative (triple-negative) are more limited since chemotherapy is not particularly effective, but research offers promise.
A 2018 study looked at the response of these tumors to mTOR inhibition (a type of targeted therapy) with the drugs Afinitor (everolimus) or Torisel (temsirolimus). It was found that people with metaplastic triple-negative breast cancers had better outcomes with this treatment than those who had non-metaplastic triple-negative tumors.
However, the inclusion of mTOR inhibitors is not standard treatment for metaplastic breast cancer. At the present time, this would only be done in the context of a clinical trial.
Clinical Trials
There are manyclinical trialsin progress for breast cancer looking for more effective treatments or ones that have fewer side effects.
While there are many myths about clinical trials, it’s important to keep in mind that every treatment currently available was once evaluated in a clinical trial, and sometimes clinical trials offer the best option for treating breast cancer. For example, the use of a P13K inhibitor (buparlisib) for metaplastic breast cancer was found to have a long-lasting response in an isolated 2018 report.
How Cancer Is Treated
Metaplastic Breast Cancer SurvivalMetaplastic breast cancer grows faster, is more likely tometastasize(spread to other parts of the body), and has a higher probability of recurring after successful treatment than other types of breast cancer. The five-year survival rate for people with metaplastic breast cancer is about 55%.
Metaplastic Breast Cancer Survival
Metaplastic breast cancer grows faster, is more likely tometastasize(spread to other parts of the body), and has a higher probability of recurring after successful treatment than other types of breast cancer. The five-year survival rate for people with metaplastic breast cancer is about 55%.
Coping With Metaplastic Breast Cancer
Having such a rare form of breast cancer may leave you feeling isolated and confused. While it’s unlikely that you have a support group for metaplastic breast cancer in your community, given how uncommon it is, you can connect with others facing this diagnosis via social media. Many people find it helpful to participate in general breast cancer support groups and support communities as well.
It’s also important to become educated about your cancer and research that is being done, and to be your own advocate (or have a friend who can advocate for or with you) in your cancer care.
After your diagnosis, you may find it disconcerting that less is known about this type of cancer. It’s sometimes helpful to seek care at one of the larger cancer centers (such as one of the National Cancer Institute-designated cancer centers), which are more likely to have surgeons and oncologists who have experience with metaplastic cases.
Summary
Metaplastic breast cancer is a rare form of invasive ductal cancer. The fast-growing cancer starts in the milk ducts and moves into other areas of the breast. Symptoms may include a lump or change in the breast or nipple, including thickening, tenderness, discharge, or irritation. It can be diagnosed through imaging such as mammography or ultrasound and a breast biopsy.
Treatment depends on the size and location of the cancer but may include surgery, radiation, hormone therapy, HER2-targeted therapies, chemotherapy, or mTOR inhibitors. Clinical trials may also provide options for treatments.
10 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Mckinnon E, Xiao P.Metaplastic carcinoma of the breast.Arch Pathol Lab Med. 2015;139(6):819-22. doi:10.5858/arpa.2013-0358-RSJohns Hopkins Medicine.Metaplastic breast cancer.Penn Medicine.HER2-Positive Breast Cancer.Tateishi K, Kiyoi M, Miyasaka M, et al.HER2-Positive Metaplastic Breast Cancer with Resistance to Neoadjuvant Chemotherapy: Case Report.Case Rep Oncol. 2023;16(1):1482-1488. Published 2023 Nov 24. doi:10.1159/000534847Leyrer CM, Berriochoa CA, Agrawal S, et al.Predictive factors on outcomes in metaplastic breast cancer.Breast Cancer Res Treat.2017;165(3):499-504. doi:10.1007/s10549-017-4367-5American Cancer Society.Hormone therapy for breast cancer.Breastcancer.org.Aromatase inhibitors.Basho RK, Yam C, Gilcrease M, et al.Comparative effectiveness of an mTOR-based systemic therapy regimen in advanced, metaplastic and nonmetaplastic triple-negative breast cancer.Oncologist.2018;23(11):1300-1309. doi:10.1634/theoncologist.2017-0498Yang M-H, Chen I-C, Lu Y-S.PI3K inhibitor provides durable response in metastatic metaplastic carcinoma of the breast: A hidden gem in the BELLE-4 study.J Formos Med Assoc. 2019;118(9):1333-1338. doi:10.1016/j.jfma.2018.12.004.MD Anderson Cancer Center.Metaplastic Breast Cancer.
10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Mckinnon E, Xiao P.Metaplastic carcinoma of the breast.Arch Pathol Lab Med. 2015;139(6):819-22. doi:10.5858/arpa.2013-0358-RSJohns Hopkins Medicine.Metaplastic breast cancer.Penn Medicine.HER2-Positive Breast Cancer.Tateishi K, Kiyoi M, Miyasaka M, et al.HER2-Positive Metaplastic Breast Cancer with Resistance to Neoadjuvant Chemotherapy: Case Report.Case Rep Oncol. 2023;16(1):1482-1488. Published 2023 Nov 24. doi:10.1159/000534847Leyrer CM, Berriochoa CA, Agrawal S, et al.Predictive factors on outcomes in metaplastic breast cancer.Breast Cancer Res Treat.2017;165(3):499-504. doi:10.1007/s10549-017-4367-5American Cancer Society.Hormone therapy for breast cancer.Breastcancer.org.Aromatase inhibitors.Basho RK, Yam C, Gilcrease M, et al.Comparative effectiveness of an mTOR-based systemic therapy regimen in advanced, metaplastic and nonmetaplastic triple-negative breast cancer.Oncologist.2018;23(11):1300-1309. doi:10.1634/theoncologist.2017-0498Yang M-H, Chen I-C, Lu Y-S.PI3K inhibitor provides durable response in metastatic metaplastic carcinoma of the breast: A hidden gem in the BELLE-4 study.J Formos Med Assoc. 2019;118(9):1333-1338. doi:10.1016/j.jfma.2018.12.004.MD Anderson Cancer Center.Metaplastic Breast Cancer.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Mckinnon E, Xiao P.Metaplastic carcinoma of the breast.Arch Pathol Lab Med. 2015;139(6):819-22. doi:10.5858/arpa.2013-0358-RSJohns Hopkins Medicine.Metaplastic breast cancer.Penn Medicine.HER2-Positive Breast Cancer.Tateishi K, Kiyoi M, Miyasaka M, et al.HER2-Positive Metaplastic Breast Cancer with Resistance to Neoadjuvant Chemotherapy: Case Report.Case Rep Oncol. 2023;16(1):1482-1488. Published 2023 Nov 24. doi:10.1159/000534847Leyrer CM, Berriochoa CA, Agrawal S, et al.Predictive factors on outcomes in metaplastic breast cancer.Breast Cancer Res Treat.2017;165(3):499-504. doi:10.1007/s10549-017-4367-5American Cancer Society.Hormone therapy for breast cancer.Breastcancer.org.Aromatase inhibitors.Basho RK, Yam C, Gilcrease M, et al.Comparative effectiveness of an mTOR-based systemic therapy regimen in advanced, metaplastic and nonmetaplastic triple-negative breast cancer.Oncologist.2018;23(11):1300-1309. doi:10.1634/theoncologist.2017-0498Yang M-H, Chen I-C, Lu Y-S.PI3K inhibitor provides durable response in metastatic metaplastic carcinoma of the breast: A hidden gem in the BELLE-4 study.J Formos Med Assoc. 2019;118(9):1333-1338. doi:10.1016/j.jfma.2018.12.004.MD Anderson Cancer Center.Metaplastic Breast Cancer.
Mckinnon E, Xiao P.Metaplastic carcinoma of the breast.Arch Pathol Lab Med. 2015;139(6):819-22. doi:10.5858/arpa.2013-0358-RS
Johns Hopkins Medicine.Metaplastic breast cancer.
Penn Medicine.HER2-Positive Breast Cancer.
Tateishi K, Kiyoi M, Miyasaka M, et al.HER2-Positive Metaplastic Breast Cancer with Resistance to Neoadjuvant Chemotherapy: Case Report.Case Rep Oncol. 2023;16(1):1482-1488. Published 2023 Nov 24. doi:10.1159/000534847
Leyrer CM, Berriochoa CA, Agrawal S, et al.Predictive factors on outcomes in metaplastic breast cancer.Breast Cancer Res Treat.2017;165(3):499-504. doi:10.1007/s10549-017-4367-5
American Cancer Society.Hormone therapy for breast cancer.
Breastcancer.org.Aromatase inhibitors.
Basho RK, Yam C, Gilcrease M, et al.Comparative effectiveness of an mTOR-based systemic therapy regimen in advanced, metaplastic and nonmetaplastic triple-negative breast cancer.Oncologist.2018;23(11):1300-1309. doi:10.1634/theoncologist.2017-0498
Yang M-H, Chen I-C, Lu Y-S.PI3K inhibitor provides durable response in metastatic metaplastic carcinoma of the breast: A hidden gem in the BELLE-4 study.J Formos Med Assoc. 2019;118(9):1333-1338. doi:10.1016/j.jfma.2018.12.004.
MD Anderson Cancer Center.Metaplastic Breast Cancer.
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