Detection of early breast cancer: an overview and future prospects

Detection and treatment of breast cancer at an early stage is the only method with proven potential for lowering the death rate from this disease. Detection of early breast cancer is promoted by the American Cancer Society, American College of Radiology, and Canadian Association of Radiologists by encouraging the regular use of three types of screening: breast self-examination, clinical breast examination, and mammography. When all factors are considered, it has been convincingly demonstrated that the potential benefits of mammography far outweigh the minimal, clinically undetected radiation risk incurred by the examination. New technologies, such as computed tomography, magnetic resonance imaging, transillumination diaphanography, ultrasound, thermography, and digital subtraction angiography might offer a wide selection for patient examination. However, none of these procedures, in its present form, is expected to replace mammography as the first-line imaging technique for the detection and diagnosis of benign and malignant breast lesions. Breast cancer is detected now, in most cases, via casual or informed breast self-examination. This first-line of detection is not sufficient, since most tumors may metastasize before they reach a palpable size. Mammography generally shows up tumors no smaller than 1-cm diameter, which in many cases have already metastasized. The more advanced imaging modalities in their current forms suffer from a number of drawbacks that give them a lower overall detection rate than mammography. Understandably, improving breast imaging modalities is a great challenge to diagnostic radiology. The purpose of this article is to provide a comprehensive overview of the detection of early breast cancer. It briefly discusses the understanding of breast cancer, its incidence, and the mortality and survival of patients with breast cancer, as well as screening programs for breast cancer. We review the developments in mammography and other breast imaging modalities over the last several years. Prospects for digital mammography, digital image enhancement, and three-dimensional digital subtraction mammography, which may someday supplant film mammography, are also discussed.