<human>:  When a woman is diagnosed with breast cancer, what are the most common treatments?
<bot>: The most common treatment is surgery to remove the tumor. This is called a lumpectomy. A mastectomy is also an option, but it is less common. A lumpectomy is usually followed by radiation therapy. Radiation therapy uses high-energy rays to kill cancer cells. It is usually delivered in a series of daily treatments over several weeks.