Understanding risk levels
People often misunderstand the concept of cancer risk levels. 重要的是要知道,大多数风险因素只会使患病几率比一般人群(基线风险)高出一点点.
For example, 如果某种东西使患某种癌症的风险增加了两倍(即风险增加了一倍), that sounds frightening. However, if the baseline risk is 1 in 100,000 – meaning that among people at average risk, 1 in 100,000人会患上这种癌症——一个风险翻倍的人仍然只有2 / 100,000 chance of getting the disease.
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Many patients who develop breast cancer don't have any known risk factors, and having risk factors doesn't mean you will get cancer. But when we know our patients' risk factors, 通过加强乳腺监测和乳腺癌预防策略,我们可以更好地保护高危人群.
Understanding family history
许多患者对有乳腺癌或卵巢癌家族史意味着什么有疑问. Doctors usually look only at close blood relatives – such as 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 higher.
If a grandmother, aunt or cousin has been diagnosed with the disease, your personal risk is usually not significantly changed, unless many of these "second-degree relatives" have had the disease.
Breast cancer risk factors
The following factors increase your risk for developing breast cancer:
- Female sex. 出生时为女性的患者占乳腺癌病例的99%以上.
- Age. The older you are, the greater your chance of getting breast cancer.
- Personal or family history. 如果你或你的近亲患有乳腺癌(包括导管原位癌),你的风险会更高, (这是乳腺癌的早期形式)或某些良性乳腺疾病(如不典型导管增生和小叶原位癌).
- Genetic predispositions. The most common examples are the BRCA1 and BRCA2 gene mutations. Each person has two copies of both genes, one from each parent. If you inherited a variant, you have a higher risk of getting several types of cancer, including breast and ovarian. For more information, 考虑和加州大学旧金山分校癌症遗传和预防项目的遗传咨询师预约一下.
- High lifetime estrogen exposure. 如果你月经来潮较早(11岁之前),你的雌激素(在女性性发育中起关键作用的激素)的累积暴露量可能会更高。, began menopause late (after age 55), 或者已经接受雌激素和黄体酮治疗(激素替代疗法)超过10年.
- Dense breast tissue. Breasts are made up of several types of tissue. Dense breasts have less fatty tissue and carry an increased risk of cancer. A mammogram can show your breast density.
- Radiation therapy in the chest area. Having undergone radiation therapy in the chest area (for example, to treat Hodgkin's lymphoma) slightly increases breast cancer risk. The increase is highest if the radiation therapy occurred before age 30.
- Race and ethnicity. 美国疾病控制与预防中心报告称,白人和非裔美国女性的乳腺癌发病率最高, followed by Asian and Hispanic women. Caucasian individuals are most likely to be diagnosed with breast cancer, but African American individuals are more likely to die from the disease.
- DES exposure. In the 1950s and 1960s, 许多孕妇服用一种叫做己烯雌酚(DES)的合成雌激素来防止流产. Females who took DES, or whose mothers took DES while pregnant with them, have a higher breast cancer risk.
The risk associated with certain other factors is less clear, but the following could increase your risk for developing breast cancer:
- Environmental pollutants. 因为研究表明,乳腺癌不能总是归因于遗传因素, 广泛的研究正在进行中,以检查可能导致乳腺癌发展的环境方面. Some studies are exploring whether exposure to environmental pollutants, such as pesticides (including DDE and DDT) and polychlorinated biphenyls (PCBs), may increase breast cancer risk, but no clear link has been established. Thus far, 有证据表明,环境污染物可能不是导致乳腺癌的主要原因.
- Hormone replacement therapy (HRT). During or after menopause, some people choose to take medications containing estrogen, with or without a form of progesterone, to relieve menopausal symptoms or for other benefits. Long-term HRT (10 years or more) may slightly increase breast cancer risk. 考虑激素替代疗法的妇女应与她们的十大赌博平台排行榜讨论决定,以确保其潜在的好处大于风险.
- Gender-affirming hormone therapy. 研究表明,与不服用这些药物的人相比,服用激素来增强女性特征(女性化激素疗法)会略微增加患乳腺癌的风险. 那些使用女性化激素治疗的人的相关风险低于普通女性. 研究还表明,服用增强男性特征的激素的人患乳腺癌的风险低于普通女性.
- Oral contraceptives. 口服避孕药(避孕药)对乳腺癌风险的影响尚未得到证实. 一些研究表明,服用口服避孕药会略微增加患病风险, other studies have shown no effect. 一项研究表明,服用口服避孕药超过12年的女性患乳腺癌的风险略高于不服用避孕药的女性. But once they had been off oral contraceptives for 10 years, their risk appeared to return to baseline.