Breast Cancer Myths and Facts: 11 Common Misconceptions Debunked

BCRF debunks persistent myths about breast cancer with research

Even as research continues to improve prevention, detection, and treatment, misinformation about breast cancer remains surprisingly common. Understanding the facts behind common breast cancer myths can help people make informed decisions about their health, recognize potential warning signs, and better understand their individual risk.

Breast cancer myths and facts: What the research shows

Thanks to research, we know more about breast cancer’s biology and how to treat it than ever before. And thanks to years of public awareness campaigns and work by organizations like the Breast Cancer Research Foundation (BCRF), more people know what breast cancer is and how commonly it occurs in women (one in eight women in the U.S. will be diagnosed in her lifetime). But unfortunately, many breast cancer myths persist online.

Here, BCRF debunks 10 common breast cancer myths with science and research. Some focus on breast cancer risk, while others involve mammograms, symptoms, genetics, or treatment. Many are blanket statements that can create confusion about how breast cancer develops and how it is detected. The following breast cancer myths and facts reflect what researchers know today.

Breast cancer myth 1: Most women diagnosed with breast cancer have a family history of the disease or a genetic mutation.

Fact: Only about 10 to 15 percent of breast cancers are caused by inherited mutations in genes like BRCA1, BRCA2, and PALB2. It’s true that research has linked certain gene mutations to an increased risk of breast cancer and that having a family history of first- or second-degree relatives with breast cancer can also elevate a person’s risk. But most women diagnosed with breast cancer have no known inherited gene mutations nor a significant family history.

Read more about inherited risk factors and hereditary breast cancer.

Breast cancer myth 2: Only women are diagnosed with breast cancer.

Fact: Although breast cancer overwhelmingly affects women (321,910 will learn they have the disease this year alone), men can also be diagnosed because they have breast tissue, too. In 2026, an estimated 2,670 men will be diagnosed and 530 will die from the disease. BCRF has supported the largest international study on male breast cancer, which revealed molecular differences in men’s tumors and noted that men tend to be undertreated, leading to worse outcomes.

Breast cancer myth 3: Only older people are diagnosed with breast cancer.

Fact: Breast cancer risk increases with age, with most diagnoses occurring in women over 50. But young women can also be diagnosed—and troublingly, incidence rates in this group are rising. Since 2012, breast cancer diagnoses in women under 50 have risen more than 1% each year. This trend has alarmed experts particularly because younger women tend to be diagnosed with more aggressive forms and at later stages, and experience worse outcomes.

Read more about breast cancer in younger women.

Breast cancer myth 4: You can’t take steps to reduce your risk of breast cancer.

Fact: Though there’s no way to totally prevent breast cancer yet, women can take steps to proactively protect their breast health:

• Learn your family history of breast and other cancers.
• Know your breasts’ “normal”.
• Eat a healthy diet, drink less alcohol, and quit smoking.
• Exercise regularly.
• Ask your doctor to do a breast cancer risk assessment.

Learn more about these and other modifiable breast cancer risk factors.

Breast cancer myth 5: Mammograms aren’t effective.

Fact: Mammograms and other forms of breast cancer screening have saved millions of lives by detecting breast cancer as early as possible, often before it can be felt. When caught early, breast cancer is nearly 100 percent curable, often with fewer, less-intense treatments and surgeries. BCRF-funded researchers are advancing mammography with new technologies like contrast-enhanced spectral mammography and AI-driven analytics to improve screening.

Read more about mammograms and breast cancer screening.

Breast cancer myth 6: Everyone’s breast cancer is the same.

Fact: Thanks to BCRF-supported research, we now know that breast cancer is, in fact, not one disease but several different diseases, each with its own drivers of growth, prognoses, and ways of responding to treatments. We’re even learning that the major subtypes of breast cancer can be further classified into sub-categories. Breast cancer research has been at the vanguard of personalized medicine, with patients getting treatments matched to their unique breast cancers. With more research into new treatments and the basic biology of breast cancer, we’ll further personalize breast cancer treatment and improve outcomes.

Read more about the major and rare types of breast cancer.

Breast cancer myth 7: Breast cancer can always be cured.

Fact: If caught early, breast cancer has a high likelihood of being cured. But devastatingly, an estimated 42,670 people will die from it this year—the vast majority from metastatic breast cancer (also known as stage 4 breast cancer). Metastatic breast cancer (MBC) occurs when breast cancer spreads to other parts of the body beyond the breast and nearby lymph nodes. Thanks to research, it can be treated, but it cannot yet be cured. While the exact number is unknowable, using statistical models based on incidence, survival, and mortality data, researchers estimate that about 169,000 people are currently living with MBC in the U.S. MBC is a major research priority for BCRF, and we’re proud to be the largest private funder of stage 4 breast cancer research in the world.

Read more about metastatic breast cancer.

Breast cancer myth 8: Breast cancer always presents as a lump.

Fact: Lumps are the best-known sign of breast cancer, but there are many other signs that might indicate an issue: breast swelling, skin dimpling, nipple discharge, a red rash, and more. Further, many women are diagnosed with breast cancer during routine breast cancer screening—well before they might even feel a lump or see another change in their breasts.

Read more about signs of breast cancer.

Breast cancer myth 9: Wire bras and antiperspirant deodorants increase your risk of breast cancer.

Fact: Even though these old claims regularly pop up across social media, they’ve been debunked by research. One benchmark 2014 study on 1,500 women concluded that bra-wearing habits—including whether someone wore an underwire, the average amount of time wearing a bra each day, and the age a woman started wearing a bra—were not associated with an increased risk of breast cancer in postmenopausal women. And according to the National Cancer Institute (NCI), no scientific evidence has linked antiperspirant deodorant with breast cancer risk or development.

Breast cancer myth 10: Eating sugar causes breast cancer to grow faster.

Fact: There are no studies showing that cutting out sugar shrinks cancer. But a diet high in sugar (particularly processed and refined sugar) can lead to obesity, inflammation, and insulin resistance—all risk factors for breast cancer and worse outcomes after a diagnosis. Eating a balanced diet that includes natural sugars (like fruits) and limits refined sugars is advisable.

Learn more about diet and breast cancer.

Breast cancer myth 11: Hormone replacement therapy always increases the risk of breast cancer.

Fact: The reality is more nuanced. Hormone replacement therapy (HRT)— which replaces hormones the ovaries no longer make as a woman enters menopause—can increase the risk of breast cancer, but not for everyone. A major 2024 study did find that risk increased when women used a combination of estrogen and progesterone therapy. The absolute risk, or the likelihood of something happening, was low compared to a placebo. And women who used estrogen-only HRT (usually women with prior hysterectomies) actually had a lower risk of breast cancer.

Learn more about hormone replacement therapy and breast cancer.

Breast Cancer Myths, Facts, and the Importance of Research

Breast cancer myths can create confusion about risk, screening, symptoms, and treatment. While some misconceptions have persisted for decades, research continues to improve our understanding of the disease and provide clearer answers for patients and families.

The more we learn about breast cancer biology, risk factors, and early detection, the better equipped people are to make informed decisions about their health. Continued investment in research is helping to replace outdated assumptions with evidence-based information—improving prevention, diagnosis, treatment, and outcomes for people affected by breast cancer.

Research is the reason we can separate fact from fiction—and your support helps make that possible. Donate, start a fundraiser, or explore other ways to give to keep that progress going.