Symptoms, causes, treatment and more

Research indicates that metaplastic breast cancer accounts for about 0.2 to 5 percent of all breast cancers. There are less than 10,000 cases per year in the United States.

Many breast cancers start in the milk ducts. Under a microscope, cancer cells look like duct cells, but they look abnormal.

Metaplastic breast cancer also begins in the milk ducts. But it looks very different under the microscope. There may be abnormal duct cells. But there are also one or more other types of cells in cancerous tissue that are not usually found here, such as those that make up the skin or bones.

Metaplastic breast cancer is usually, but not always triple negative. This means that it lacks estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor 2 (HER2).

Metaplastic tumors tend to be high grade. This means that cancer cells are very different from normal cells and reproduce at a high rate. Unlike other types of breast cancer, it is more likely to be metastatic and spread to the lungs or bones than the lymph nodes.

Symptoms of metaplastic breast cancer are the same as most other types of breast cancer. These may include:

• a lump or thickening on the chest
• change in the size or shape of the breast
• puckering or padding of the skin
• nipple rotating inward
• nipple discharge
• breast pain

Cancer begins with DNA damage that allows abnormal cells to grow out of control. It is not known exactly why a person develops breast cancer.

According to National Institutes of Health (NIH), there is no inherited genetic risk factor for predisposition to metaplastic breast cancer. The cause of this type of cancer is not known.

Known risk factors for any breast cancer include:

• age – more breast cancers are diagnosed after 50 years
• hereditary genetic mutations, such as BRCA1 and BRCA2
• personal or family history of breast or ovarian cancer
• first period before age 12 and menopause after age 55
• physical inactivity
• overweight or obese after menopause
• taking hormone replacement therapy or certain oral contraceptives
• drinking alcohol

Since metaplastic breast cancer is rare, the exact incidence of BRCA1 and BRCA2 mutations is not known in this type of cancer.

Metaplastic breast cancer is diagnosed the same way as other types of breast cancer. This may include:

A biopsy is the only way to confirm a diagnosis of breast cancer. After taking a tissue sample from the tumor, a pathologist examines it under a microscope. The presence of several types of cells may suggest that it is metaplastic breast cancer. Your biopsy results will contain additional information, such as:

• ER, PR and HER2 status
• tumor grade

Treatment is similar to that for other types of breast cancer, including local and systemic therapy. Most metaplastic breast cancers are also triple negative, which means they cannot be treated with hormone therapy. But they are more likely be locally advanced as triple negative breast cancer and may not respond as well to chemotherapy.

Your treatment plan will be based on the characteristics of your cancer, such as:

• tumor size
• tumor grade
• hormone receptor (HR) status
• HER2 status

Surgery

Breast cancer surgery may involve:

• Breast-conserving surgery, also called lumpectomy, is a procedure in which the surgeon removes the tumor and a margin of healthy tissue around it.
• Mastectomy is surgery to remove the entire breast.

The type of surgery you choose depends on several factors. These include the size and number of tumors and personal preferences.

Chemotherapy

Chemotherapy destroys cancer cells all over the body and may reduce the risk of spread and recurrence. Chemotherapy can take place before or after surgery.

Radiotherapy

Radiotherapy Usually follows breast-conserving surgery to target cancer cells that may have been left behind. It can also be used after a mastectomy. Radiation can be directed at the tumor site or nearby lymph nodes.

Drug therapy

The choice of which drug treatment to use depends on the characteristics of the cancer.

Hormone therapy is used to treat HR-positive breast cancer. These drugs help block or stop hormones from fueling cancer. Metaplastic breast cancer is more likely to be HR negative, in which case hormone therapy is not an option.

Most metaplastic breast cancers are also HER2-negative. But if yours is HER2-positive, you may benefit from targeted therapies As:

• monoclonal antibodies
• antibody-drug conjugate (ADC)
• kinase inhibitors

Genetic profiling can help doctors provide more targeted treatments. Researchers have identified various molecular abnormalities that could lead to more targeted therapies. An example of this is a protein called PD-L1.

Research published in 2021 examined the combination of chemotherapy drugs and pembrolizumab, a PD-L1 antibody. Positive responses to this combination therapy have been observed in tumors with intermediate expression of PD-L1.

A Case report 2021 involved a 72-year-old woman with stage 4 triple-negative metaplastic breast cancer. Her cancer tested positive for PD-L1. She was treated with pembrolizumab for 2 years, during which time she also had the operation. After 32 months, the scans showed no signs of illness and she maintained a good quality of life.

Metaplastic breast cancer has a poorer prognosis than other types of breast cancer. He has twice the risk of recurrence is shorter disease-free survival and overall survival than triple negative non-metaplastic breast cancer.

Research shows that between 2010 and 2014, women diagnosed with metaplastic breast cancer were more likely to be older at diagnosis. They also had more comorbid conditions (other conditions that occur at the same time) than women with other breast cancers.

At a median follow-up of 44.5 months, the overall survival rates were:

• Step 1: 85 percent
• 2nd step : 73 percent
• step 3: 43 percent

The 3-year overall survival rate for metastatic disease (stage 4) was 15 percent. The result was not affected by hormonal or HER2 status. The worst results were associated with:

• increasing age
• advanced stage
• lymphovascular invasion
• Axillary lymph node dissection vs sentinel lymph node dissection
• no radiation
• no chemotherapy

There are many factors that affect your outlook. After reviewing your tests and medical history, your oncologist can provide you with a more personalized prognosis and an idea of ​​what to expect from treatment.