Metaplastic squamous cell breast cancer is an exceedingly rare form of the disease, accounting for less than 0.1 percent of breast cancer cases, according to a study published in the journal Onkologie in 2007. Cells in a metaplastic squamous cell carcinoma of the breast have a flattened squamous shape, which is used to help diagnose the disease. This form of cancer is generally aggressive and often fails to respond to hormone-based therapies, but it may respond to other cancer treatments.
Mastectomy
The primary treatment for metaplastic squamous cell carcinoma of the breast is a mastectomy, a breast-removing surgery. Since metaplastic squamous cancer cells are typically invasive and aggressive, surgeons often perform aggressive surgeries to fight the cancer. During a mastectomy, the surgeons excise the metaplastic squamous tumor along with any remaining breast tissue, the breast skin and nipple, and layers of chest muscle underneath the cancerous breast. The doctors also remove a series of small structures called lymph nodes, since invasive breast cancers often invade lymph nodes around the breast. Following surgery, patients with metastatic squamous cell breast cancer may receive additional cancer treatments.
Adjuvant Chemotherapy
Many breast cancer patients with metaplastic squamous cell carcinoma receive adjuvant chemotherapy--drug therapy designed to kill cancer cells and shrink breast tumors. Chemotherapy drugs are designed to inhibit normal processes in the cell as well as damage essential cellular structures, essentially damaging the cancer cell and preventing it from making the chemicals it needs to survive. Patients with metaplastic squamous cell breast cancer may receive a number of chemotherapy treatments, either alone or in combination, depending on the aggressiveness and characteristics of the tumor. The use of adjuvant chemotherapy can lead to a number of side effects, such as nausea, fatigue and hair loss, though these effects subside after cessation of treatment.
Targeted Therapy
Some patients with metaplastic squamous cell breast cancer may receive targeted therapies--drugs that identify and kill cancer cells by targeting proteins found on the cells' surface. A study published in the Journal of Clinical Oncology in 2005 indicates that many patients with metaplastic squamous cell breast cancer have tumors containing a protein called epidermal growth factor receptor, or EGFR. Under normal conditions, EGFR aids in cell growth by promoting cell division. Some metaplastic squamous cell breast cancers begin to overproduce the EGFR protein, causing constant cell proliferation and driving cancer growth. Drugs that target EGFR, such as ZD1839, can therefore target and kill metaplastic squamous cell cancers in some cases. Patients looking to receive targeted therapies must first undergo medical testing to assess whether their cancer will likely respond to specific drugs.
