Taking Charge: 谁会患上乳腺癌?
There are no rules about who gets this disease. The two most significant risk factors are being a woman, and increasing age. 然而, there are other factors that may increase your risk, and some that may lower it.
The development of breast cancer may be influenced by factors that affect the levels of female hormones that circulate in your body throughout life. These factors include the age when you began your menstrual period, the number of times you have been pregnant, 你第一次怀孕的年龄, whether you have breastfed your children, and your level of physical 活动.
Explaining the concept of cancer risk is one of the ongoing challenges of public health education. Medical research has defined risk factors for developing breast and ovarian cancer by studying large populations of women. It is important to remember that most risk factors increase the chance of getting cancer by only a small amount above the general or "baseline" risk.
例如, if something increases the risk of developing cancer by a factor of 2 — meaning that the risk is doubled — that sounds frightening. 然而, if the baseline risk of getting the cancer is 1 in 100,000, doubling the risk means that the figure is still only 2 in 100,000.
鉴于这一信息, an individual woman will not know whether having a particular risk factor means she will get cancer. Rather, it is one of many factors that can guide her in making health and lifestyle choices.
Women are often confused by what it means to have a family history of breast or ovarian cancer. 利来登录 usually look only at very close blood relatives — your mother, sisters and daughters — when determining your family history of these diseases. If one or more of these relatives has had breast or ovarian cancer, your own risk is significantly increased.
如果一个祖母, aunt or cousin has been diagnosed with the disease, 然而, your personal risk is usually not significantly changed, unless many of these "secondary" relatives have had the disease.
Risk Factors for 乳腺癌
- 年龄The older you are, the greater your chance of getting breast cancer. Experts believe that one in eight women who live to age 80 will get the disease. About 77 percent of women are over age 50 at the time they are diagnosed with breast cancer; less than 1 percent are diagnosed in their 20s. When younger women — those who have not gone through 更年期 — get the disease, it may be a faster-growing breast cancer.
- 家族病史If you have a close blood relative — a mother, sister or daughter — who has had breast cancer, your own risk for developing the disease doubles. If two of these relatives have the disease, your risk increases five times.
In many cases where breast cancer seems to run in families, 突变特定基因的突变, 叫做BRCA1和BRCA2, may be contributing to the cancer. Genetic tests are available to see if a woman carries this mutation. 然而, genetic testing is a complex area. If you have concerns about your family history, you should consult a doctor and a genetic counselor who can help you weigh the benefits and risks of testing.
- 个人历史A woman with cancer in one breast has a three to four-fold increased risk of developing a new cancer in the other breast.
- 比赛White women are slightly more likely to develop breast cancer than are African-American women. African-Americans are more likely to die of this cancer, 然而. Asian and Hispanic women have a lower risk of developing breast cancer.
- 其他乳房疾病Although most benign breast disease does not increase your risk of developing breast cancer, a 活组织检查 result that shows a condition called atypical hyperplasia, or proliferative breast disease without atypia, does increase the risk to some extent.
- 以前的乳房辐照If you received radiation therapy to your chest when you were a child or young woman — for example, for treatment of Hodgkin's disease or non-Hodgkin's lymphoma — your risk of developing breast cancer is slightly increased.
- 月经If you started menstruating before age 12 or if you went through 更年期 after age 50, your risk for breast cancer is slightly increased.
- 口服避孕药Women who use oral contraceptives (birth control pills) may under certain circumstances have a slightly greater risk of getting breast cancer, 但两者之间的联系尚不清楚.
- 没有孩子如果你没有孩子, or had your first child after age 30, your risk for breast cancer is slightly increased. Having an abortion or miscarriage does not seem to affect the overall risk.
- 非母乳喂养Your breast cancer risk may be slightly lowered if you breastfeed your children, especially if you continue nursing for 1.5 - 2年.
- Hormone Replacement Therapy (HRT)Some women choose to take hormones containing estrogen, with or without a form of progesterone, 绝经期后. Long-term use — 10 years or more — of HRT may slightly increase the risk of breast cancer. The risk seems to return to normal within five years of stopping HRT. This risk must be weighed against the many health benefits of using HRT.
- 酒精This is clearly linked to an increased risk for breast cancer. Those who have two to five alcoholic drinks daily have 1.5 times the risk for developing breast cancer as women who do not drink. Reducing your alcoholic intake to no more than three servings per week is recommended.
- 体重和饮食女人 超重, especially 绝经期后, are at increased risk for breast cancer. Researchers believe that this is because fat tissue can make estrogen, and exposure to estrogen is linked to breast cancer. Researchers have not yet found a clear link between high-fat 饮食s and breast cancer, although such a relationship has been shown for other cancers.
- 体育活动Recent studies indicate that even moderate exercise may help to lower your breast cancer risk. This link is being investigated further.
- Exposure to Environmental PollutantsResearch has not shown a clear link between breast cancer risk and exposure to pollutants such as pesticides (DDE and DDT) and polychlorinated biphenyls (PCBs). 然而, the subject of environmental pollutants and cancer is complex and requires further study.
- Next section of Taking Charge: If You Are at High Risk for 乳腺癌
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加州大学旧金山分校健康 medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.