Metaplastic breast cancer explained

Metaplastic breast cancer (MpBC) is a rare type of fast-growing breast cancer that can spread anywhere in the body. Doctors often detect it in the later stages, so it is not curable, but treatment can help people manage the disease.
The World Health Organization (WHO) classified MpBC as a separate disease in 2000, and it is responsible for less than 1% of breast cancer cases.
less than 1%
In this article, we discuss the symptoms, diagnosis, and treatment of MpBC. We also look at the outlook for people with this type of cancer.
What is MpBC?
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The Greek term metaplasia means a change of form. Under a microscope, MpBC cells might look like a mix of breast cells and other cells, such as:
means
cartilage
muscle
bone
skin
connective tissue
The different shapes and features of these cells tell pathologists the subtype of MpBC. There are several subtypes of MpBC, and the treatment is typically the same for all types.
several
MpBC is an aggressive and invasive type of cancer, meaning that it multiplies quickly and can spread throughout the body. MpBC tends to spread or metastasize more than other breast cancers, often traveling to the lungs.
What are the symptoms of MpBC?
Many symptoms of MpBC are the same as those of other types of breast cancer. The symptoms may include:
a new lump in the breast, which is typically larger than in other breast cancers, often measuring more than 2 centimeters
2 centimeters
changes in the shape and size of the breast
dimpling breast skin
dimpling breast skin
discharge from the nipple, other than breast milk
the nipple turning in toward the breast
pain in the breast
A person with any of these symptoms should speak with a doctor as soon as possible.
Diagnosing MpBC
When a person first receives a breast cancer diagnosis, they are unlikely to know the specific type. A doctor will perform a biopsy so that a pathologist can examine the cancer cells under a microscope.
perform a biopsy
MpBC cells contain two or more cell types, and their appearance determines the subtype. A study notes that the WHO recognizes the following cell types in MpBC:
study
adenosquamous
carcinosarcoma
chondroid
osseous
spindle cell
squamous
As well as establishing the subtype, a pathologist grades cancer from 1–3. Grade 1 means that the cancer cells are growing relatively slowly, while grade 3 means that they are reproducing more rapidly, and the cancer may spread quicker.
Most people with MpBC have grade 3 when they receive their diagnosis.
Doctors also determine whether the cancer is triple-negative. Many breast cancer cells have receptors for estrogen, progesterone, or human epidermal growth factor receptor 2 (HER2). Whether the cancer cells have any of these receptors influences the treatment options.
determine
Most, but not all, MpBCs are triple-negative, which means that they do not have any of these three receptors.
Most
Doctors use breast cancer staging to describe whether cancer has spread and how much of the body it affects. Higher stage numbers mean that cancer has spread further. People with MpBC usually have stage 2 or higher on diagnosis.
describe
Treating MpBC
As MpBC is a rare and only recently recognized disease, doctors usually treat it the same way as other breast cancers. A doctor will discuss the treatment options — which will depend on the cancer’s grade, stage, and triple-negative status — with the individual.
Doctors often suggest a combination of surgery and systemic, or whole body, treatments, such as chemotherapy or immunotherapy.
However, MpBC is difficult to treat. The overall outcomes are less positive than they are for other invasive breast cancers, and there is an increased risk that the cancer will recur or return.
less positive
invasive breast cancers
increased risk
After treatment
MpBC carries a higher-than-usual risk of spreading throughout the body, so people with MpBC need regular monitoring after the initial treatment.
A person may need additional tests and treatments, depending on where in the body the cancer has spread. Doctors may suggest blood tests and imaging tests alongside regular physical exams.
Outlook
The 5-year disease-specific survival rates for people with MpBC are much less positive than those for people with other invasive breast cancers. A 2015 study of survival outcomes lists this survival rate as 78% for MpBC compared with 93% for invasive ductal carcinoma (IDC), the most common form of breast cancer.
2015 study
Outcomes may also vary depending on the subtype of MpBC. The squamous subtype seems to have the lowest 5-year disease-specific survival rate, at 56%.
56%
Research into MpBC and clinical trials investigating targeted treatments are ongoing.
Living with MpBC
Cancers that have spread are known as metastatic or stage 4 cancers. Doctors cannot cure these cancers, but treatments can help people manage the symptoms and improve their quality of life.
Living with cancer can affect people emotionally, financially, and socially, as well as physically.
Many people with metastatic MpBC may feel overwhelmed, and although this is a normal reaction, it could lead to chronic stress and depression. Anxiety and depression may have adverse effects on the recurrence of breast cancer and the survival rates of people with the disease.
adverse effects
Confidence and quality of life play a key part in how a person with MpBC may feel every day. Changes in body image may make a person with MpBC wish to avoid social situations.
Even among people with health insurance, money worries may lead to people delaying treatment or missing doses of their medications.
lead to
A person should talk with their healthcare team about any of these issues. These healthcare professionals may help by:
recommending organizations that provide financial assistance
offering counseling, support groups, or both
advising individuals to contact a social worker at their doctor’s office
Caregivers or family members may also need some support.
Summary
MpBC is a rare, aggressive, and invasive form of breast cancer.
As it does not respond well to treatment, the outcomes are generally less positive than they are for other types of breast cancer.
Ongoing cancer treatment and support may help improve a person’s quality of life.