What are basic facts about breast cancer?

Updated: Feb 04, 2021
  • Author: Pavani Chalasani, MD, MPH; Chief Editor: John V Kiluk, MD, FACS  more...
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Worldwide, breast cancer is the most frequently diagnosed life-threatening cancer in women. In many less-developed countries, it is the leading cause of cancer death in women; in developed countries, however, it has been surpassed by lung cancer as a cause of cancer death in women. [2] In the United States, breast cancer accounts for 30% of all cancers in women and is second only to lung cancer as a cause of cancer deaths in women. [3] (For discussion of male breast cancer, see Breast Cancer in Men.)

Many early breast carcinomas are asymptomatic; pain or discomfort is not usually a symptom of breast cancer. Breast cancer is often first detected as an abnormality on a mammogram before it is felt by the patient or healthcare provider.

The general approach to evaluation of breast cancer has become formalized as triple assessment: clinical examination, imaging (usually mammography, ultrasonography, or both), and needle biopsy. (See Workup.) Increased public awareness and improved screening have led to earlier diagnosis, at stages amenable to complete surgical resection and curative therapies. Improvements in therapy and screening have led to improved survival rates for women diagnosed with breast cancer.

Surgery and radiation therapy, along with adjuvant hormone or chemotherapy when indicated, are now considered primary treatment for breast cancer. For many patients with low-risk early-stage breast cancer, surgery with local radiation is curative. (See Treatment.)

Adjuvant breast cancer therapies are designed to treat micrometastatic disease or breast cancer cells that have escaped the breast and regional lymph nodes but do not yet have an established identifiable metastasis. Depending on the model of risk reduction, adjuvant therapy has been estimated to be responsible for 35-72% of the decrease in mortality.

Over the past 3 decades, extensive and advocate-driven breast cancer research has led to extraordinary progress in the understanding of the disease. This has resulted in the development of more targeted and less toxic treatments. (See Treatment and Medication.)

For patient education information, see Breast Cancer and Breast Cancer Diagnosis: Screening, Detection, and Testing.

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