Mastectomy (noun)

1. A surgical operation to remove a breast, typically as a treatment for breast cancer.
2. The surgical removal of a breast, usually as a treatment for breast cancer.

Origin:

From greek μαστός (mastos, "breast") + -ectomy.

Examples:

1. She underwent a mastectomy to treat her breast cancer.
2. The mastectomy was followed by radiation therapy.
3. The patient had a double mastectomy as a preventative measure.
4. The mastectomy was performed as a last resort, after other treatments failed.
5. The patient faced a difficult recovery after the mastectomy.