Risk Factors for Breast Cancer
Question: How do I know if I'm at risk for breast cancer?
Answer: Less than 30 percent of breast cancer cases can be attributed to known risk factors or genetics, according to the Breast Cancer Action Kit. For the remaining 70 percent, the causes aren't fully understood.
The greatest risk factor is gender. Women account for nearly all cases, as only about 1,000 males are diagnosed per year. All women age 40 and above are at risk, with most breast cancers occurring over age 50. In fact, by age 40, a woman's chance of being diagnosed with breast cancer is one out of 235; at age 50, it becomes one out of 54; by age 60, it's one out of 23.
Other significant risk factors for developing breast cancer include:
- Early age at onset of menstruation
- Late age at onset of menopause
- First full-term pregnancy after age 30
- History of pre-menopausal breast cancer in mother or a sister
- A personal history of breast cancer or of benign proliferative breast disease
- Smoking cigarettes
- Radiation exposure
Environmental factors such as groundwater pollution and living in urban areas have also been associated with breast cancer risk.
Of special note to women in their 40s and 50s who are approaching or in menopause: Breast cancer risk may increase by up to 40 percent in post-menopausal women who have used hormone replacement therapy (HRT) for five or more years. This breast cancer-HRT link has been shown in various medical studies, notes Malcolm C. Pike, Ph.D., and Flora L. Thornton, Professor in the Department of Preventive Medicine at the Keck School of Medicine at the University of Southern California. "When using estrogen replacement therapy (ERT) alone for five or more years," says Dr. Pike, "the effect can be as much as 10 percent."
Bottom line for survival: Early detection.