Incidence and death from breast cancer
Breast cancer is the most common noncutaneous cancer in U.S. women, with an estimated 61,000 cases localized to the breast, 246,660 cases of invasive disease, and 40,450 deaths expected in 2016. Thus, fewer than one of six women diagnosed with breast cancer die of the disease. By comparison, it is estimated that about 72,160 American women will die of lung cancer in 2016. Men account for 1% of breast cancer cases and breast cancer deaths
Widespread screening increases breast cancer incidence in a given population and changes the characteristics of cancers detected, with increased incidence of lower-risk cancers, premalignant lesions, and ductal carcinoma in situ (DCIS). In the last decade, women have refrained from using postmenopausal hormones, and breast cancer incidence has declined, but not to the levels seen before the widespread use of screening mammography.
Risk factors for developing breast cancer
Risk factors for breast cancer include the following:
1. Female sex and increasing age are the most important risk factor for breast cancer.
2. Family health history.
3. Major inheritance susceptibility (women who inherit genes associated with breast cancer).
4. Mutation of the genes BRCA1 and BRCA2, and other breast cancer susceptibility genes.
5. Alcohol intake.
6. Increased breast tissue density.
7. Estrogen (endogenous):
8. Use of combination estrogen plus progestin hormone replacement therapy (HRT).
10. Personal history of breast cancer.
11. Personal history of proliferative forms of benign breast disease.
12. Race (more white women get breast cancer, but more black women die from it).
13. Radiation exposure to the breast/chest.
Of all women with breast cancer, 5% to 10% may have a mutation of the genes BRCA1 and BRCA2. Specific mutations of BRCA1 and BRCA2 are more common in women of Jewish ancestry. The estimated lifetime risk of developing breast cancer for women with BRCA1 and BRCA2 mutations is 40% to 85%. Carriers with a history of breast cancer have an increased risk of contralateral disease that may be as high as 5% per year. Male BRCA2 mutation carriers also have an increased risk of breast cancer.
Mutations in either the BRCA1 or the BRCA2 gene also confer an increased risk of ovarian cancer [48,49] or other primary cancers. Once a BRCA1 or BRCA2 mutation has been identified, other family members can be referred for genetic counseling and testing.[
Factors that decrease the risk of female breast cancer
Protective factors and interventions to reduce the risk of female breast cancer include the following:
1. Estrogen use (after hysterectomy).
3. Early pregnancy.
5. Treatment with selective estrogen receptor modulators (SERMs) such as tamoxifen (Soltamox) and raloxifene (Evista).
6. Treatment with aromatase inhibitors such as exemestane (Aromasin).
7. Risk-reducing mastectomy.
8. Risk-reducing oophorectomy or ovarian ablation.
NIH: National Cancer Institute