Common Myths and Realities about the Causes of Breast Cancer

There's a lot of information out there about breast cancer. Let's take a deep dive into the myths and realities you may have heard.
breast cancer concept

Breast cancer affects approximately one in eight women in their lifetime. Women of all nationalities, faiths, ages, and lifestyles dread the possibility of developing breast cancer. Although we have gained a better understanding of its triggers, it often strikes women with no known risk factors. This uncertainty can lead people to speculate wildly on what causes lead to this devastating disease. Let us break down which of these speculations have merit and which are baseless.

Family History—Reality

A family history of either breast or ovarian cancer does indeed increase the risk of being diagnosed with breast cancer. Having a first-degree relative, meaning a parent, sibling, or child diagnosed with breast cancer, greatly increases the risk of developing it yourself. This is especially true if familial breast cancer occurred before the age of 40, affected both breasts, was diagnosed in multiple relatives, or was diagnosed in a male relative.

If this describes you or someone you love, a risk assessment is recommended. While it is important to be vigilant about testing, it is not a reason to panic. While it does increase the risks, it does not guarantee cancerous cells will develop.


Because mammograms involve both exposure to radiation and compression of the breast tissue, some people believe mammograms may induce breast cancer. Mammograms require very low dosages of radiation, however—not enough to induce the formation of cancer. Although compressing the breast fully is more likely to diagnose breast cancer, this is because full compression gives the radiologist a better view of the breast, not because it triggers the cancer to grow or spread.

Mammograms are recommended for all women over 40.

Cell Phones—Myth

woman on phone

Cell phones emit low-energy radiation that some believe may cause cancers. A few studies have found a tenuous link between the excessive use of cell phones and breast cancer. However, the studies have been done on very small samples or have been problematic in other ways, such as focusing on brain cancer rather than breast cancer. The issue is still being studied, but to date, the majority of the research does not support the claim that cell phone use causes any sort of cancer, including breast cancer.


There is some speculation that wearing an underwire bra or wearing a bra to bed can cause cancer to form by blocking the lymph nodes. Although it is true that an ill-fitting bra can lead to discomfort, swelling, and pain, there is no evidence that supports the theory that any type of bra can induce cancer.

Genetic Changes and Mutations—Reality

There are several genetic mutations and changes that correlate to a higher chance of developing breast cancer. The most commonly known genetic mutations that can increase the risk are mutations to the BRCA1 and BRCA2 genes. These genes are responsible for making proteins that repair damaged DNA, and mutations can sometimes lead to abnormal cell growth that can contribute to cancer.

Several less common gene mutations are also known to increase risk. These can include changes to other genes responsible for DNA repair, the TP53 gene, which can cause Li-Fraumeni syndrome, which increases the risk of cancer of all types, and the PTEN gene, which helps regulate cell growth, among others.

Genetic testing can be helpful in some cases, especially for those with a strong family history, but there are pros and cons to this type of testing. If you are concerned about your chances of a genetic mutation in your family, set an appointment with your doctor to discuss the ins and outs of genetic testing.

Big Breasts—Myth

woman with large chest

It seems logical that larger breasts would be more likely to develop cancer; after all, there is more breast material to develop cancer in. It turns out that this is untrue, however. Although bigger-breasted women may end up with larger tumors than average, the size of the breast itself does not lead to a greater chance of cancer being diagnosed.

Dense Breasts—Reality

Although larger breasts are not more prone to developing cancer, high-density breasts are more likely to develop tumors, though the reasons for this are not well understood. Breasts that are dense have more supportive tissue than fatty tissue, appearing as a solid white area on a mammogram. Less dense breasts have more fatty tissue, which shows up as a dark or transparent area on a mammogram. The appearance of dense breast tissue on a mammogram may also make it more difficult for a radiologist to spot tumors in dense breasts. This can increase the likelihood of the cancer growing and spreading before detection.


Caffeine can lead to several health problems, including insomnia, headaches, increased heart rate, and ulcers. Breast cancer, however, is not included in the list of caffeine’s conundrums. Studies to determine whether or not caffeine spurred the formation of breast cancer found no conclusive link between caffeine consumption and higher incidences of breast cancer. Interestingly, they did find that caffeine and coffee were marginally protective against breast cancer for women who carry BRCA1 mutations.

Sugar—Myth (mostly)

There is a commonly repeated myth that sugar and sugary foods feed cancer cells, fueling greater growth. While it is true that cancerous cells consume more sugar than healthy cells, studies so far have indicated no direct link between sugar intake and breast cancer. There is, however, a link between breast cancer and diabetes and obesity and breast cancer. Both conditions can be driven by excess sugar and processed carbohydrates in the diet, causing an indirect link.


Saying no to a glass of red wine, drinking in moderation

Alcohol consumption does indeed increase the risk of breast cancer. According to the World Health Organization, alcohol is a Group 1 human carcinogen. It’s linked to at least seven types of cancer, at least one of which is breast cancer. In addition, alcohol increases the amount of estrogen in the body, adding another layer of risk to the development of cancer in the breast. Just one to two drinks a day can increase the risk of breast cancer by 30%-50%. Greater quantities induce a greater risk. Neither the type nor quality of the alcohol changes these risks.

The Quest to Understand Cancer

Breast cancer, like all cancers, is a complex disease that generates a lot of misinformation. It is the most common cancer among women in the United States, but each year, more women survive breast cancer. Catching cancers early dramatically improves the chance of a positive outcome. Knowing more about what does and does not lead to breast cancer can help you to make informed decisions. Informed medical decisions can help to catch cancers earlier and can also improve your life by reducing anxiety.

Read Next:

7 Healthy Habits to Decrease the Risk of Breast Cancer

Braving Breast Cancer: Tales of Tenacity, Humor, and Healing

6 Ways to Support a Loved One with Breast Cancer


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