What Causes Breast Cancer? Risk Factors - Fact v. Fiction

Some breast cancer risks are more real than others. Screenings, risk assessments – and definitely mammograms – are among the best strategies for early detection and healthy outcomes.

Can antiperspirant cause cancer?

For any person worried that using deodorant or antiperspirant can cause breast cancer, stop sweating it.

“I think this idea stems from people trying to find an answer, because we all know loved ones, friends and family members who are diagnosed with breast cancer,” said Ellie Proussaloglou, MD, a surgical oncologist who specializes in breast surgery for L+M Hospital, Smilow Cancer Hospital and Yale Medicine.

The good news, Dr. Proussaloglou reports, is that, based on many years of studies, there is no evidence that any antiperspirant or deodorant – including those containing aluminum and phthalates – directly cause breast cancer.

“The thought behind antiperspirants and deodorants causing cancer is this fear that, because these products temporarily block the sweat glands, toxins can be trapped in the underarm,” Dr. Proussaloglou said. “However, what we know about the biology of our bodies, and how the breasts function, is that most toxins are processed by the liver and the kidneys and excreted out through urine or our GI tract. Based on what we know right now – and of course we’re always learning more – this is just a myth.”

However, she hopes that patients asking about causes of cancer are open to learning more, because there are other well documented risk factors for breast cancer that people should take seriously.

Smoking and cancer risk

“Many of the components in cigarettes, vapes and blunts can cause carcinogenic or tumor-promoting changes in tissue throughout the body, and can increase your risk of many cancers,” Dr. Proussaloglou said. “Anything that increases your cell turnover in a bad way can increase the risk of breast cancer.”

Similarly, minimizing intake of processed foods and red meats, and eating fruits and vegetables in a manner consistent with the Mediterranean Diet, has been shown to decrease some cancer risks. Regular exercise is also considered helpful.

How much does drinking increase cancer risk?

“We’ve seen again and again that even moderate alcohol intake – which, for women, is defined as one drink a night – has been associated with increased breast cancer risk over time,” Dr. Proussaloglou said. “We know that binge drinking, or heavy drinking, has many consequences for the body, but even moderate intake of alcohol can increase your breast cancer risk.

“If I see someone who is at high risk for breast cancer, then I definitely encourage them to minimize alcohol intake. We don’t really know what a safe level is, so I always suggest my patients keep alcohol as a rare indulgence rather than an everyday thing, because alcohol has been associated with an increased risk of breast cancer.”

Family history of cancer - Assessing risk and taking action

If breast cancer or other types of cancers run in your family, it may be important to talk to your doctor about genetic testing. There are some genes associated with cancer risk that contribute to about 10 percent of breast cancers diagnosed in the US.

Some of these genes are more strongly linked with cancer than others. For example, the BRCA gene has been linked with cancer development. There are two types of BRCA genes, BRCA 1 and BRCA 2, and most people have normal functioning copies of these genes, one from each parent.

“However,” Dr. Proussaloglou said, “if you inherit a copy that is abnormal or pathogenic, it increases the risk of multiple cancers. BRCA 2 increases the risk of breast cancer, ovarian cancer, pancreatic cancer, prostate cancer, male breast cancer, and there’s some evidence it also increases the risk of melanoma, which is one of the more aggressive skin cancers.

“Many times, when I see people who test positive for BRCA 2, they will have a family history of breast or gynecologic cancers but sometimes we have families where the cancers we find are the rarer associated cancer types, such as a pancreatic in grandpa, and maybe an aggressive prostate cancer in an uncle. These patients may not realize they’re at high risk for breast cancer because they’re not seeing a pattern they expected.”

All women or patients born female should discuss their breast cancer risk with their primary healthcare providers, and this should include discussing family history, Dr. Proussaloglou said. “A lot of people don’t talk about talk about cancer history with their families because it can be emotional and feel very private. But knowledge is power. I tell my patients, ask your mom, ask your dad, ask your grandmother. Those patterns of breast, ovarian, pancreatic, prostate cancer are things you should talk about with your doctor, to see if genetic testing would be helpful.”

Recommendations for mammogram screening

The American Society of Breast Surgeons recommends initiation of mammograms at age 40 (and also ultrasound testing for women with dense breast tissue) and repeating those tests every one or two years based on conversations with your doctor. However, “if someone in your family has had a breast cancer diagnosis earlier than age 40, you can request a risk assessment and determine if you qualify for earlier screening, such as starting mammograms closer to age 30 or 35. We often recommend getting your first mammogram 10 years before the age of the youngest family member diagnosed with breast cancer.”

Mammograms are crucially important because, aside from risk factors, 70 percent of breast cancers are sporadic, meaning they’re random, and the main risks are being female and getting older. About 20 percent of cancers run in families, and only about 10 percent are hereditary or genetic and due to gene variants, according to Dr. Proussaloglou.

Debunking another myth, Dr. Proussaloglou notes that radiation from X-rays used for mammograms is not dangerous. “The exposure is lower than all our normal activities, like flying on a plane or using a microwave,” she said.

“With all cancers, early detection is key to help decrease the amount of treatment you need and to decrease negative consequences,” Dr. Proussaloglou said. “Early detection can keep you healthy and save lives, and while it’s often top of mind during Breast Cancer Awareness Month in October, it should be something we think about all year round. Anything people can do to gather their strength to talk to their doctors and go to their screenings, I really encourage it.”

YNHHS uses the terms "female" and "male" to reflect biological status typically assigned at birth, and "women" and "men" when referring to gender. According to the Human Rights Campaign, a doctor or midwife assigns a child's sex, male, female or intersex at birth based on their external anatomy. Gender identity is one's innermost identification of self as male, female, a blend of both or neither. Gender identification may differ from birth sex.