Understand · Risk + Screening
An overview of breast cancer risk and screening
About 1 in 8 women in the U.S. will be diagnosed with breast cancer in her lifetime, and the two biggest risk factors are ones nobody chooses: being a woman and getting older. Some risk you can lower, some you can measure, and some you can only watch for. For most women, that means regular mammograms starting at 40, knowing your family history, and knowing what your own breasts normally look and feel like.
What to know about breast cancer risk and screening
- Family history isn't the whole story. Only about 5 to 10 in 100 breast cancers are thought to be inherited.
- Screening now starts at 40. The national task force recommends a mammogram every two years from 40 to 74. The American Cancer Society favors yearly mammograms for many of those years.
- Dense breasts are common. Nearly half of women 40 and older who get mammograms have them, and your report now has to tell you.
- Some risks are in your hands. Alcohol, weight after menopause and activity all play a part, though none of them is a guarantee either way.
- New changes deserve a visit. A lump, skin or nipple changes, or discharge should be checked promptly.
One note before we start: these answers are written for women who haven't had breast cancer. If you have, your screening plan is different and is set with your care team. If you've just been diagnosed, start here.
1. If most women with breast cancer have no family history, why should I worry about my risk?
That's true. Breastcancer.org and the American Cancer Society both say only about 5% to 10% of breast cancers are thought to be hereditary. That's exactly why screening is for everyone. The ACS calls being born female the main risk factor. The second is age: Breastcancer.org says about two out of three invasive breast cancers are found in women 55 or older, and the ACS puts the median age at diagnosis at 63. Neither shows up on a family tree. Family history still matters (the ACS says one mother, sister or daughter with breast cancer almost doubles a woman's risk), but having none doesn't let you skip mammograms. Our guide to breast cancer risk factors goes through the full list.
2. Can breast cancer be prevented?
Not completely, but you can shift the odds. The American Cancer Society estimates that about 30% of breast cancers can be linked to things that can potentially be changed, chiefly extra body weight, not moving much and drinking alcohol.
Alcohol. The CDC says even one drink a day may raise risk. The ACS says no amount is completely safe, risk climbs with each extra drink, and women who drink should have no more than one a day.
Weight after menopause. The ACS says extra weight after menopause raises risk, and gaining weight then raises it further.
Movement. The ACS suggests 150 to 300 minutes of moderate activity a week, or 75 to 150 minutes of vigorous activity.
Smoking. Breastcancer.org links it to higher risk in younger women before menopause. The ACS says the link is harder to pin down because many people who smoke also drink.
What you can't change: being a woman, your age, your genes, your family history, when your periods started and stopped, and dense breast tissue. Women who do everything "right" still get breast cancer. It isn't a report card.
3. How can I find out my own breast cancer risk?
Start with your family. Write down who on both sides, your father's as well as your mother's, has had breast, ovarian, pancreatic or prostate cancer, and how old they were when they were diagnosed. Bring it to your clinician.
Your clinician may also use a risk calculator. The best-known is the National Cancer Institute's Breast Cancer Risk Assessment Tool (the Gail model), which uses your age, reproductive history, close relatives with breast cancer and past biopsies. It has limits: NCI says it isn't meant for women with a past breast cancer, chest radiation for Hodgkin lymphoma or a known BRCA change, and it may underestimate risk for some Black women with past biopsies and some Hispanic women born outside the U.S.
The number matters: the ACS says women with a lifetime risk of about 20% or higher should usually add a yearly breast MRI to a yearly mammogram, typically from age 30.
4. When should mammograms start, how often should you get one, and do breast self-exams still matter?
The U.S. Preventive Services Task Force (April 2024) recommends a mammogram every two years for women 40 to 74. For women 75 and older, it says there isn't enough evidence to weigh the benefits and harms.
The American Cancer Society says women at average risk can choose to start yearly mammograms at 40, should have them every year from 45 to 54, and then can switch to every other year at 55 or stay yearly. It says screening should continue as long as a woman is in good health and expected to live at least 10 more years.
Both put 40 on the table. They differ on how often, and when to stop.
Self-exams and clinical exams. The ACS says routine self-exams and exams by a clinician aren't enough to screen women at average risk. It does say every woman should know how her breasts normally look and feel and report any change right away, which doctors call breast self-awareness. The task force's recommendation doesn't address either kind of exam.
5. What does it mean to have dense breasts, and what should you do about it?
Dense breasts have more gland and fibrous tissue and less fat. It's a description, not a disease, and the National Cancer Institute says nearly half of women 40 and older who get mammograms have them. It matters twice over: dense tissue and tumors both look white on a mammogram, so a cancer can be harder to see, and dense breasts carry a higher risk of breast cancer than fatty ones.
Since September 2024, an FDA rule has required mammography facilities to tell you in your results letter whether your breast tissue is dense.
What comes next is less settled. The ACS says ultrasound or MRI can find some cancers a mammogram misses, but also turn up more things that aren't cancer, meaning more tests and biopsies, and insurance may not cover them. The task force says there isn't yet enough evidence to recommend for or against extra screening for dense breasts. The ACS says experts don't agree on which extra tests, if any, to use. Some studies suggest 3D mammography (tomosynthesis) may help.
6. Do birth control pills or menopausal hormone therapy raise breast cancer risk?
Birth control. Studies find a small rise in risk while women use hormonal birth control, which fades after they stop. A large pooled analysis described by NCI found current pill users had a 24% higher risk than never-users. A 2017 Danish study found about 20% higher risk with modern hormonal contraception. In absolute terms that's small: as Breastcancer.org reported, the Danish study worked out to about one extra breast cancer for every 7,690 women using hormonal contraception for a year, and about one per 50,000 among women under 35. The ACS says risk seems to return to normal within a few years of stopping; NCI's summary says no extra risk was seen by 10 years. Breastcancer.org notes that women who have had breast cancer generally shouldn't use hormonal birth control.
Menopausal hormone therapy. The type matters. In the large Women's Health Initiative trials, estrogen plus progestin (taken by women who still have a uterus) raised breast cancer risk, and NCI says that higher risk lasted at least a decade after stopping. Estrogen alone (taken by women who've had a hysterectomy) was linked to a lower risk of breast cancer and of dying from it. The ACS adds that risk is higher with longer use, higher doses and starting after 60.
In November 2025 the FDA announced it would remove breast cancer and other risk statements from the boxed warning on menopausal hormone therapy, and in February 2026 it approved the new labels for several products. That changed the label, not the trial results, so talk through your own risks with your clinician.
7. How do pregnancy and breastfeeding change breast cancer risk?
Pregnancy. NCI says women whose first full-term pregnancy came before 20 have about half the risk of women whose first came after 30, though that applies only to hormone receptor-positive breast cancer. The ACS says never being pregnant, or having a first pregnancy at 35 or older, slightly raises risk.
Right after a birth. Risk rises for a while after having a baby, then declines after about 10 years, NCI says.
Breastfeeding. NCI says breastfeeding for at least a year is linked to a lower risk of both hormone receptor-positive and receptor-negative breast cancer. The ACS describes the benefit as slight.
8. Do radiation, chemicals or the environment cause breast cancer?
Radiation to the chest at a young age is a clear risk. Breastcancer.org and the ACS single out chest radiation before age 30, such as treatment for Hodgkin lymphoma. The ACS recommends earlier screening with MRI for these women.
Most chemicals are an open question. The ACS says no studies have shown a clear link between breast cancer and phthalates, chemicals in some plastics and personal care products that can act like estrogen. Studies of certain pesticides and PCBs haven't shown higher risk. That research, like research on night shift work, is ongoing.
Some worries can be put down. The ACS says there's little if any reason to think antiperspirants raise risk, and no evidence that wearing a bra changes it. Its 2024 report also lists abortion and breast implants as not linked to breast cancer risk.
9. Who should get genetic testing for breast cancer risk?
Not everyone needs it, but some women should have it. Changes in the BRCA1 and BRCA2 genes are the best-known, and NCI says women who inherit a harmful change in either one have a lifetime breast cancer risk of more than 60%, compared with about 13% for women in general. (The ACS says up to 70%.) The ACS lists other genes that raise risk too, including PALB2, CHEK2, ATM, TP53, PTEN and CDH1.
The task force recommends that primary care clinicians use a short family history tool to screen women with a personal or family history of breast, ovarian, tubal or peritoneal cancer, or an ancestry linked to BRCA changes, such as Ashkenazi Jewish heritage. Those who screen positive should get genetic counseling, then testing if appropriate; women without those flags shouldn't be routinely tested. (That guidance is from 2019; an update is in progress.)
NCI adds other reasons to ask: a relative with a known BRCA change, breast cancer at 50 or younger, or a family history of ovarian, male breast, pancreatic or advanced prostate cancer. A genetic counselor helps you decide whether to test, and what a result would mean, before you do.
10. How does race affect breast cancer risk and survival?
Yes, and mostly not in the way the numbers first suggest. According to the American Cancer Society, Black women are slightly less likely than White women to be diagnosed with breast cancer, 131.3 versus 137.9 cases per 100,000 women a year. But their death rate is 38% higher. The task force puts it at about 40%.
The ACS says Black women are diagnosed at a younger median age (61 versus 65), have higher rates of breast cancer before 40, and are about twice as likely to have triple-negative or inflammatory breast cancer, which tend to be more aggressive. Only 58% of Black women are diagnosed at the earliest, localized stage, compared with 68% of White women.
Biology is only part of it. The ACS points to later diagnosis and less access to timely, high-quality treatment, and says Black women have lower survival at every stage. The task force calls screening from 40 an important first step for Black women, but says fair follow-up and treatment matter just as much. If you're a Black woman, it's worth asking about your risk before 40, and asking how quickly an abnormal result would be followed up.
When to see a clinician about a breast change
- A new lump in your breast or armpit
- Thickening or swelling in part of your breast
- Dimpled, irritated, red or flaky skin on the breast or nipple
- A nipple that pulls inward, or pain in the nipple area
- Nipple discharge that isn't breast milk, especially if it's bloody
- A change in the size or shape of your breast, or pain anywhere in it
The CDC says to see your doctor right away for any of these. Conditions other than cancer can cause them too, which is why they deserve a proper look.
If it feels like an emergency, call 911.
Questions to ask your clinician about breast cancer risk and screening
- Based on my history, is my risk average, higher than average or high?
- Should we use a risk calculator, and what does my number mean?
- When should I start mammograms, and should I go every year or every other year?
- Are my breasts dense, and do I need anything beyond a mammogram? Would my insurance cover it?
- Does my family history mean I should see a genetic counselor?
- Does my birth control, or the hormone therapy I'm considering, change my risk?
- If my mammogram shows something, how quickly will I get follow-up testing?
Sources: U.S. Preventive Services Task Force, Breast Cancer: Screening (April 30, 2024) and BRCA-Related Cancer: Risk Assessment, Genetic Counseling, and Genetic Testing (August 20, 2019; update in progress); American Cancer Society, Recommendations for the Early Detection of Breast Cancer, Key Statistics for Breast Cancer (revised June 2026), Breast Cancer Facts & Figures 2024–2025, Cancer statistics for African American and Black people, 2025 (CA: A Cancer Journal for Clinicians), Risk factors you cannot change, Lifestyle-related risk factors, Disproven or controversial risk factors and Breast density and your mammogram report; National Cancer Institute, Dense Breasts (updated December 2025), BRCA Gene Changes (reviewed July 2024), Oral Contraceptives and Cancer Risk (reviewed February 2018), Menopausal Hormone Therapy and Cancer (reviewed September 2023), Reproductive History and Cancer Risk (reviewed November 2016) and About the Breast Cancer Risk Assessment Tool; CDC, Reducing Risk for Breast Cancer and Symptoms of Breast Cancer (both reviewed September 2026); FDA, Understanding Breast Density (June 2026) and FDA Approves Labeling Changes to Menopausal Hormone Therapy Products (February 2026); Breastcancer.org, Breast Cancer Risk Factors (updated June 2026), Do Hormonal Contraceptives Increase Breast Cancer Risk? (December 2017) and Do Antiperspirants Increase Breast Cancer Risk? (updated July 2026). This article is general information, written in Babette's own words, and is not a substitute for advice from your care team.
