Breast Cancer
The diagnosis and treatment of breast cancer have changed dramatically during the past two decades. Screening programs did not exist 25 years ago. The preferred treatment was radical mastectomy, and adjuvant therapy did not exist. This is in marked contrast to the current situation of well-organized screening programs, effective adjuvant therapy, and alternative treatment.
The most recent figures from the National Cancer Institute reveal that after a sharp rise in the percentage of women diagnosed with breast cancer from 1980 to 1987, there has been a decline in incidence, especially among women 50 years of age and older. The lifetime risk for developing breast cancer is one in nine. This reflects an increase in life expectancy of American women and the fact that breast cancer is a disease of older women. In addition, the increase is the result of the decision to include in the calculation women older than 85 years of age.
The American Cancer Society predicted 180,200 new cases of breast cancer and 43,900 deaths for 2006, representing 31% of all new cases of cancer and 17% of cancer deaths. The mortality rate for breast cancer has been unchanged since 1930, increasing on an average of 0.2% per year from 1973 to 1990, but decreasing in women under age 65 years by an average of 0.3% per year. Recent data, however, indicate that breast cancer mortality has decreased in whites by almost 5% from 1989 to 1992, probably as a result of an increase in the diagnosis of localized cancer and the increased use of adjuvant therapy and screening mammography.
The most important risk factor for breast cancer is advancing age. In women older than age 45 years, breast cancer occurs more frequently in upper socioeconomic classes, and whites are affected more than African Americans. Identified risk factors, either alone or in combination, explain only 21% of the risk among women age 30-54 years and 29% of the risk among women age 5584 years. Thus, from a practical standpoint, 80% of the women with breast cancer have none of the currently identified risk factors, and the clinician should assume that all women are at risk, particularly those older than 35 years of age.
Early detection is associated with increased survival and more cosmetic local treatment. Women should undergo screening and routine surveillance at timely intervals to assess risks and aid in early diagnosis. It is recommended that screening mammography be offered routinely every 1-2 years to women age 40-49 and annually to women older than age 50. Women age 35 and older with premenopausally diagnosed breast cancer in a first-degree relative also should be offered mammography.