Breast cancer is the second most common cancer in women after skin cancer, with cancer related mortality only exceeded by lung cancer. Breast cancer is most often caused by a number of various genetic insults leading to dysplastic cellular changes; only a small minority is clearly linked to heritable mutations in the BRCA1 and BRCA2 tumor suppressor genes. However BRCA positivity is a strong risk factor for cancer development, with both BRCA1- and BRCA2-positive individuals at significantly increased risk for breast cancer. Other risk factors for breast cancer include earlier age of menarche, later age of menopause, nulliparity, and late age of first birth, all of which determine the cumulative number of ovarian cycles. Obesity, alcohol use, older age, decreased physical activity, other genetic and environmental factors as well as hormone replacement therapy (HRT) have also been linked to risk for breast cancer. The Breast Cancer Risk Assessment Tool, based on the Gail model, is an interactive tool designed by scientists at the National Cancer Institute (NCI) and the National Surgical Adjuvant Breast and Bowel Project (NSABP) to estimate a woman's risk of developing invasive breast cancer. Available online, this tool calculates a 5-year breast cancer risk in women ages 35 and older based on ethnicity, current age, age of menarche, age of first live birth, and history of breast biopsy or history of any breast cancer or of ductal carcinoma in situ (DCIS) or lobular carcinoma in situ (LCIS).
Claus EB, Risch N, Thompson WD: Autosomal dominant inheritance of early-onset breast cancer. Implications for risk prediction. Cancer. 1994 Feb 1;73(3):643-51.
Primary and Secondary Prevention
Breast cancer in the general population is often discovered on examination and/or mammography. While these techniques have clearly reduced the risk of breast cancer death through earlier detection, neither technique is perfect. False-positive results are a source of considerable anxiety, cost, and morbidity—especially in younger populations who are much more likely to have benign breast disease. Computer-aided detection (CAD) and enhanced digital technologies may improve accuracy of mammography. However, screen film mammography is the gold standard for breast cancer screening. As a result of emerging evidence about the potential harms of early screening, controversy surrounds the ideal age of initiation of mammogram surveillance and appropriate screening intervals for breast cancer in the general population, as well as the efficacy of breast self examination. Previously, there had been a relatively broad consensus among multiple professional organizations that 40 years of age was the ideal age to institute screening mammography. In 2009, however, US Preventive Services Task Force (USPSTF) endorsed 50 rather than 40 years as the recommended age for initiation of mammogram screening in the general population, revising an earlier recommendation. A summary of current recommendations from the American Cancer Society, American College of Gynecologist and Obstetricians, as well as the USPSTF is found in Table 26-1. Recommendations ...