Worldwide, breast cancer is by far the most common cancer among women. It occurs twice as often as colorectal cancer and cervical cancer and three times as often as lung cancer. About 1.3 million women are diagnosed with breast cancer annually, and about 465,000 will die from it. North America has the highest rate of breast cancer in the world. A woman living in the US has a 1-in-8 chance of having malignant breast cancer at some time during her life (up from 1 in 20 in 1960), and a 1-in-35 chance of dying from it. According to the American Cancer Society, about 182,500 women in the United States will have been diagnosed with invasive breast cancer in 2008.

However, there is good news. In the last 20-30 years, tremendous strides have been made in the detection and treatment of breast cancer, thanks in part to breast cancer activists who have helped raise both awareness and funds and who have spurred research on the disease. In 1975, any form of breast cancer was usually treated by radical mastectomy. Today this operation is rare, having largely been replaced by surgeries that spare the breast as much as possible, more targeted radiation therapy, and new and improved chemotherapy. Breast cancer is being caught earlier, when treatment results are usually better. Breast cancer death rates among women have been in steady decline since 1990.