What Are Risk Factors
The exact cause of breast cancer is unknown. But certain things can increase your chance of developing it. These are called risk factors. The risk factors for invasive breast cancer and ductal carcinoma in situ are similar.
Having one or more risk factors does not mean you will definitely get breast cancer. And if you do not have any risk factors, it does not mean you will not get it.
Breast cancer is likely to be caused by a combination of different risk factors, rather than just one.
If you are worried about breast cancer and would like to talk to someone, we’re here. You can:
More Evidence Ties Some Antipsychotics To Increased Breast Cancer Risk
Megan Brooks
New research provides more evidence that antipsychotics that raise prolactin levels are tied to a significantly increased risk for breast cancer.
The relative risk for breast cancer was 62% higher in women who took category 1 antipsychotic medications associated with high prolactin levels. These include haloperidol , paliperidone , and risperidone . Additionally, the risk was 54% higher in those taking category 2 antipsychotics that have mid-range effects on prolactin. These include iloperidone , lurasidone , and olanzapine .
In contrast, category 3 antipsychotics which have a lesser effect on prolactin levels were not associated with any increase in breast cancer risk. These drugs include aripiprazole , asenapine , brexpiprazole , cariprazine , clozapine , quetiapine , and ziprasidone .
Dr Tahir Rahman
While the “absolute” breast cancer risk for these drugs is unclear, “we can make the case that high circulating prolactin levels are associated with breast cancer risk. This follows what is already known about prolactin from prior studies, notably the nurses’ health studies,” Tahir Rahman, MD, associate professor of psychiatry, Washington University School of Medicine, St. Louis, Missouri, told Medscape Medical News.
The study was December 3 in the Journal of Clinical Psychopharmacology.
How Do Doctors Assess Risk For Breast Cancer
Theres currently no standardized approach to assessing an individuals breast cancer risk. However, there are several tools that help doctors identify those at a high risk of breast cancer.
Breast cancer risk assessment tools are heavily based on your personal and family history. However, they do take other factors into account as well. A few examples of commonly used tools include the:
- Breast Cancer Risk Assessment Tool , also called the Gail model
- International Breast Cancer Intervention Study risk calculator, also called the Tyrer-Cuzick model
- Claus model, based off the Cancer and Steroid Hormone Study
Risk assessment tools provide a variety of measurements. These can include 5-year risk, 10-year risk, and lifetime risk.
Whats considered high risk can vary by location. In the United States, people with an estimated 5-year risk of 1.67 percent or higher are typically considered high risk.
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Common Risks For Breast Cancer
According to the National Cancer Institute below are the factors that increase a womens risk of getting breast cancer:
The strongest risk factor for breast cancer is age. A womans risk of developing this disease increases as she gets older. The risk of breast cancer, however, is not the same for all women in a given age group. Research has shown that women with the following risk factors have an increased chance of developing breast cancer.
Genetic alterations : Inherited changes in certain genes increase the risk of breast cancer. These changes are estimated to account for no more than about 10 percent of all breast cancers. However, women who carry changes in these genes have a much higher risk of breast cancer than women who do not carry these changes.
Family history: A womans chance of developing breast cancer increases if her mother, sister, and/or daughter have been diagnosed with the disease, especially if they were diagnosed before age 50. Having a close male blood relative with breast cancer also increases a womans risk of developing the disease.
Personal history of breast cancer: Women who have had breast cancer are more likely to develop a second breast cancer.
Alcohol: Studies indicate that the more alcohol a woman drinks, the greater her risk of breast cancer.
Long-term use of menopausal hormone therapy: Women who used combined estrogen and progestin menopausal hormone therapy for more than 5 years have an increased chance of developing breast cancer.
Radiation Exposure To The Chest

Repeated and overexposure of the chest to radiation as a child or as a young adult before the age of 30 years as in radiotherapy can increase your breast cancer risks later in life. This risk greatly increases especially if radiation exposure occurs when the breast cells are first being formed during the prenatal period or during early adolescence.
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Being Overweight Or Obese
Women who are overweight after their menopause have a higher risk of breast cancer than women who are not overweight. Men also have an increased risk of breast cancer if they are overweight or obese. For both men and women, the risk increases as more weight is gained.
Body mass index is a measure that uses your height and weight to work out whether you are a healthy weight. For most adults, an ideal is between 18.5 to 24.9. Being overweight means having a BMI of between 25 and 30. Obesity means being very overweight with a BMI of 30 or higher.
Try to keep a healthy weight by being physically active and eating a healthy, balanced diet.
Drinking alcohol increases the risk of breast cancer in women. The risk increases with each extra unit of alcohol per day. The number of units in a drink depends on the size of the drink, and the volume of alcohol.
The latest UK government guidelines advise drinking no more than 14 units of alcohol a week.
Personal History Of Early Breast Cancer
Women diagnosed with invasive breast cancer are at a higher risk of developing cancer in their other breast.
There are also a number of non-invasive breast conditions that are associated with an increased risk of breast cancer. These include ductal carcinoma in situ , lobular carcinoma in situ and atypical ductal hyperplasia .
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Why Is Screening So Important
While some tumors in the breast are aggressive and grow quickly, most grow slowly. In some cases a tumor may have been growing for as long as 10 years before it creates a lump large enough to feel. That means that even if you know whats normal for your breasts and notice when something changes, you may not feel anything until the cancers been growing for a while.
Screening tests can find breast cancer early, when the chances of survival are highest. They can find breast cancer in a person who doesnt have any early signs or symptoms. For people at a higher risk, more frequent screening can mean that if they do develop cancer, they can find it and treat it sooner.
The Advancing Age Risk
The risk of breast cancer increases with age and more so after the age of 55 years. Young women are at a lesser risk. Only about 5% of breast cancer cases are seen in women below the age of 40 years. Most breast cancers are diagnosed in women after age 50 years.
About 80% of women diagnosed with breast cancer each year are 45 years or older, and about 43% are 65 years old or above.
Risk evaluation by age:
- In women between the ages 40 to 50 years, the risk of developing breast cancer is one in 69.
- Between the ages 50 to 60, that risk increases to one in 43.
- In the 60 to 70 year age group, the risk further increases to one in 29.
- In women 70 years and older, the risk is highest at one in 26
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What Does High Risk For Breast Cancer Really Mean
One out of every eight women will develop breast cancer in their lifetime this is considered average risk for U.S. women. High risk for breast cancer is defined as a greater than or equal to 20% lifetime risk, or in other words, a one in five chance of developing breast cancer over a lifetime. We all know someone a coworker, family member such as a mother, sister, daughter or friend that has been diagnosed with this disease.
Thats why for decades, October and the color pink have gone hand in hand to promote Breast Cancer Awareness. Regular screenings and a healthy lifestyle have been shown to reduce a womans risk for developing breast cancer. In addition to these important actions, you need to be aware of our own individual lifetime risk for breast cancer. Summa Health answers your top questions about what it means to be high risk and how you can take charge of your breast health this month and every month to reduce your risk of breast cancer or detect it at its earliest stages when it is most treatable and curable.
How do I know my risk for Breast Cancer?
The risk for breast cancer is not the same for all women, as it depends on your individual health history and family history. A high risk designation can be determined by one factor or a combination of factors.
What factors increase my risk for Breast Cancer?
If You Have Had Breast Cancer Before
Your risk of developing invasive breast cancer is increased if you have had breast cancer or ductal carcinoma in situ before.
In this case, you will have regular follow-up appointments. Any changes in the same breast or the other breast can be checked quickly.
Having certain breast conditions can also increase the risk of developing breast cancer:
- Lobular carcinoma in situ
LCIS is also called lobular neoplasia. This is when there are abnormal cell changes in the lining of the lobules.
- Atypical ductal hyperplasia
This is when there are slightly abnormal-looking cells in the milk ducts in a small area of the breast.
Women with these non-cancerous conditions are usually monitored regularly, so any changes can be found early.
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Breast Cancer Surveillance Consortium Risk Calculator
The Breast Cancer Surveillance Consortium Risk Calculator was developed and validated in 1.1 million women undergoing mammography across the United States, of whom 18,000 were diagnosed with invasive breast cancer. The BCSC Risk Calculator has been externally validated in the Mayo Mammography Health Study. In 2015, the BCSC risk calculator was updated to include benign breast disease diagnoses and to estimate both 5-year and 10-year breast cancer risk.
How Could Oral Contraceptives Influence Cancer Risk

Naturally occurring estrogen and progesterone stimulate the development and growth of some cancers . Because birth control pills contain synthetic versions of these female hormones, they could potentially also increase cancer risk.
In addition, oral contraceptives might increase the risk of cervical cancer by changing the susceptibility of cervical cells to persistent infection with high-risk HPV types .
Researchers have proposed multiple ways that oral contraceptives may lower the risks of some cancers, including:
- suppressing endometrial cell proliferation
- reducing the number of ovulations a woman experiences in her lifetime, thereby reducing exposure to naturally occurring female hormones
- lowering the levels of bile acids in the blood for women taking oral conjugated estrogens
Selected References
Burkman R, Schlesselman JJ, Zieman M. Safety concerns and health benefits associated with oral contraception. American Journal of Obstetrics and Gynecology 2004 190:S522.
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Neoplastic And Benign Risk Factors
Neoplastic conditions that increase the risk of breast cancer include the following:
- Previous breast cancer
- Ductal carcinoma in situ
- Lobular carcinoma in situ
Benign breast conditions that slightly increase the risk of breast cancer include the following :
- Hyperplasia
- Sclerosing adenosis
- Microglandular adenosis
Interestingly, a personal history of cervical cancer is associated with a lower incidence of developing breast cancer.
Endogenous Sex Hormone Blood Concentration Hormonal Therapy And Breast Cancer Risk
A high endogenous estrogen level is a well-defined risk factor contributing to a higher incidence of breast cancer. The analysis of prospective studies confirmed a strong association between increasing concentrations of sex hormones in postmenopausal women and a higher breast cancer risk . The significance of these data among premenopausal women is less clear partially because of a cycle-dependent variability of the hormone concentration in this group. Available studies on large cohorts of observed participants suggest that levels of circulating estrogens and androgens may also play an important role in the etiology of premenopausal breast cancer . The results of the Nurses Health Study II support another thesis that premenopausal levels of estrogens and androgens may be important for the development of postmenopausal disease. The influence of serum hormone levels on the risk of development of different breast cancer subtypes according to the receptor status was studied by Farhat et al. . The analysis revealed that higher serum levels of bioavailable testosterone may be associated with lower risks of ER-negative breast cancer. On the other hand, both testosterone and estradiol were correlated with an increased risk of ER-positive disease in postmenopausal women.
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Alcohol And Breast Density Marker
In addition to the carcinogenic role of its metabolites, alcohol has been shown to alter estrogen levels, which may lead to changes in breast density, affecting breast cancer risk . An intermediate marker of breast cancer risk that has also been linked with many hormonal breast cancer risk factors is mammographic density, a measure of epithelial and connective tissue in the breast. Higher density confers a 4-6 fold increase in breast cancer risk . Moreover, alcohol use has been shown to modify the mammographic density-breast cancer association in a dose-response way . Associations between alcohol use and intermediate markers such as breast density provide further evidence that alcohol is truly associated with breast cancer and that this association cannot be explained by bias alone.
Epidemiologic studies have used different measures to assess mammographic density with earlier studies using qualitative measures such as the Wolfe parenchymal patterns , and more recent studies using more quantitative methods that either use categories such as the Breast Imaging Reporting and Data System or use a continuous measure ranging from 0-100% based on computer threshold programs .
Breast Cancer: Risk Factors And Prevention
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ON THIS PAGE: You will find out more about the factors that increase the chance of developing breast cancer. Use the menu to see other pages.
A risk factor is anything that increases a persons chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. Knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.
Most breast cancers are sporadic, meaning they develop from damage to a persons genes that occurs by chance after they are born. There is no risk of the person passing this gene on to their children, as the underlying cause of sporadic breast cancer is environmental factors.
Inherited breast cancers are less common, making up 5% to 10% of cancers. Inherited breast cancer occurs when gene changes called mutations are passed down within a family from parent to child. Many of those mutations are in tumor suppressor genes, such as BRCA1, BRCA2, and PALB2. These genes normally keep cells from growing out of control and turning into cancer. But when these cells have a mutation, it can cause them to grow out of control.
The following factors may raise a womans risk of developing breast cancer:
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Breast Cancer Causes And Risk Factors Explained
Worldwide statistics on breast cancer tell you breast cancer is the most common cancer in women and the second most common cancer overall. In the United States, it is the second most common cancer among women after skin cancer.
What then are the breast cancer causes and risk factors that have made it a global epidemic?
What exactly causes it is still uncertain but certain risk factors that you make prone are ascertained through studies.
What Are The Recommendations For Early Detection
Those at a high risk of breast cancer can benefit from additional monitoring or screening. This can help to detect and begin treatment for breast cancer early.
Doctors may also spread out screening tests by 6 months to increase surveillance to two times a year, rather than once a year. For example, they may recommend a mammogram in January and an MRI in June.
Currently, the ACS recommends that the following people receive both a mammogram and a breast MRI each year, often starting at age 30:
- those with a lifetime risk of breast cancer of 20 to 25 percent or more based on risk assessment tools
- individuals with a known mutation in BRCA1 or BRCA2 or those who have a close relative with a known BRCA1 or BRCA2 mutation
- people who received radiation therapy to their chest area between the ages of 10 and 30
- those with a personal or family history of the following family cancer syndromes:
- Li-Fraumeni syndrome
- Cowden syndrome
- Bannayan-Riley-Ruvalcaba syndrome
There are benefits to using both types of screening technology. Although a breast MRI is more likely to find cancer, it may miss changes that a mammogram would detect.
Additionally, the ACS states that theres currently not enough evidence to recommend a yearly breast MRI for people with dense breasts or a history of breast conditions like DCIS, LCIS, ADH, and ALH.
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