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.
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.
The Greek term metaplasia
- connective tissue
The different shapes and features of these cells tell pathologists the subtype of MpBC. There are
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.
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
- changes in the shape and size of the breast
- 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.
When a person first receives a breast cancer diagnosis, they are unlikely to know the specific type. A doctor will
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:
- spindle cell
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.
Most, but not all, MpBCs are triple-negative, which means that they do not have any of these three receptors.
Doctors use breast cancer staging to
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.
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.
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.
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%.
Research into MpBC and clinical trials investigating targeted treatments are ongoing.
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
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
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.
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.