The numbers: how many women get breast cancer

About 1 in 8 women in the United States will develop breast cancer at some point in her lifetime. In any given year, roughly 300,000 new cases of breast cancer are diagnosed in American women. The risk is not evenly distributed across age groups — most cases occur in women over 50, but breast cancer does occur in younger women too.

These figures come from the National Cancer Institute and the American Cancer Society, which track cancer diagnoses through registries that collect data from hospitals and clinics across the country. The numbers have remained relatively stable over the past decade, though they rose slightly in the 1990s and early 2000s before leveling off.

Key Takeaways

  • About 1 in 8 women will develop breast cancer in her lifetime, with roughly 300,000 new cases diagnosed each year in the United States.
  • Risk increases with age — most breast cancers occur in women over 50, but younger women can develop it too.
  • Breast cancer rates vary by race and ethnicity, with Black women having higher mortality rates despite similar or slightly lower incidence rates.
  • Survival rates have improved over the past 30 years due to earlier detection and advances in treatment.
  • Having risk factors like family history or dense breast tissue increases individual risk, but most women with risk factors never develop breast cancer.

How breast cancer risk changes with age

Age is the strongest predictor of breast cancer risk. A 30-year-old woman has roughly a 1 in 227 chance of developing breast cancer in the next 10 years. By age 50, that risk rises to about 1 in 42 over the next 10 years. At age 70, the 10-year risk is approximately 1 in 27.

This age pattern means that while breast cancer can occur at any age after puberty, the vast majority of cases — about 80 percent — occur in women 50 and older. Breast cancer in women under 40 is less common but still significant in absolute numbers, accounting for roughly 5 percent of all breast cancer cases.

Differences in breast cancer rates by race and ethnicity

Breast cancer incidence rates vary by racial and ethnic group. White women have the highest incidence rate overall, followed by Black women, Hispanic women, Asian and Pacific Islander women, and American Indian and Alaska Native women. However, this pattern does not tell the full story about who faces the greatest burden from breast cancer.

Black women have lower incidence rates than white women but significantly higher mortality rates — meaning they are more likely to die from breast cancer once diagnosed. This disparity reflects differences in access to screening, quality of care, and treatment options, as well as biological factors that are still being studied. Hispanic women and Asian and Pacific Islander women have lower incidence and mortality rates than white and Black women.

Risk factors that increase individual breast cancer risk

Certain characteristics and life circumstances increase a woman's individual risk above the baseline 1 in 8 figure. A family history of breast cancer — particularly in a mother, sister, or daughter — raises risk. Inherited mutations in the BRCA1 or BRCA2 genes carry much higher lifetime risk, around 70 percent by age 80. Dense breast tissue, detected on a mammogram, also increases risk.

Other factors that raise risk include starting menstruation before age 12, reaching menopause after age 55, having no children or having a first child after age 30, current or recent hormone therapy use, obesity, and alcohol use. Importantly, having one or more risk factors does not mean a woman will develop breast cancer — most women with risk factors never do. Risk assessment tools can help individual women understand their personal risk level.

How detection and treatment have changed the picture

The five-year survival rate for breast cancer has improved substantially over the past 30 years, from about 75 percent in the early 1990s to over 90 percent today. This improvement reflects both earlier detection through mammography screening and advances in treatment, including targeted therapies and immunotherapies that work against specific types of breast cancer.

Mammography screening has increased the proportion of breast cancers caught at earlier stages, when treatment is more effective and less invasive. However, screening also detects some cancers that would never have caused harm — a phenomenon called overdiagnosis. This is one reason why screening recommendations vary by age and risk level, and why the decision to screen involves weighing benefits and risks.

What these statistics mean for individual women

Population statistics describe patterns across millions of women but do not predict what will happen to any individual. A woman's actual risk depends on her specific combination of age, family history, reproductive history, lifestyle factors, and genetic makeup. Two women of the same age can have very different risk levels.

Understanding the baseline statistics — that breast cancer is common but most women do not develop it, that risk rises with age, and that survival has improved — provides context for conversations with a doctor about personal risk and screening decisions. A healthcare provider can assess individual risk factors and discuss what screening or prevention strategies make sense for a particular woman's situation.

Frequently Asked Questions

Does having a mother with breast cancer mean I will definitely get it?

No. Having a close relative with breast cancer increases your risk, but most women with a family history never develop breast cancer themselves. Your actual risk depends on details like the relative's age at diagnosis, whether she had one or both breasts affected, and whether genetic testing has identified a mutation in your family.

Why do Black women have higher death rates if they have lower incidence rates?

The difference reflects multiple factors: Black women are more likely to be diagnosed at later stages, may have less access to certain treatments, and face systemic barriers in healthcare. Biological differences in tumor type may also play a role. These disparities are not due to differences in biology alone but to structural inequities in the healthcare system.

If I have dense breast tissue, how much does that increase my risk?

Dense breast tissue roughly doubles breast cancer risk compared to fatty tissue. However, doubling a baseline risk of 1 in 8 still means most women with dense breasts will not develop cancer. Dense tissue also makes mammograms less sensitive, which is why supplemental screening with ultrasound or MRI may be recommended.

Are breast cancer rates going up or down?

Overall rates have been relatively stable for the past 15 years. Rates rose in the 1990s and early 2000s, partly due to increased screening and hormone therapy use. Rates among younger women have increased slightly in recent years, but the reasons are not fully understood.

What percentage of women with risk factors actually get breast cancer?

This varies widely depending on which risk factors are present. A woman with no special risk factors has roughly a 12 percent lifetime risk. A woman with a BRCA1 mutation has around a 70 percent risk by age 80. Most women fall somewhere in between, and having multiple risk factors raises risk more than having just one.