Hormones and cancer: What's the link?

Hormones have a lot of power. They are the tiny chemicals that tell your body – right down to the cells – what to do. They determine everything from how big you will grow, to how you process food, to how your immune system works.

Hormones can affect your weight, your body temperature and even your mood. They can also have an impact on your cancer risk, says Therese Bevers, M.D., medical director of MD Anderson’s Cancer Prevention Center.

“When people hear the word hormone, they think of estrogen and progesterone, and their effects on female cancers,” Bevers says. “But there are several other hormones that have an impact on your risk of cancer throughout the body.”

Making the connection between hormones and cancer

What’s the link between hormones and cancer risk? It has a lot to do with cells multiplying.

And the more your cells divide and multiply, the more chance there is for something to go wrong and for cancer to develop.

There are several things that can affect your hormones, including medications, chronic inflammation and medical conditions like obesity. For other factors, like toxins and diet, the link to cancer risk is less clear.

Birth control pills

Birth control pills  control fertility with doses of the female sex hormones estrogen and progesterone. They may lower the risk for ovarian and endometrial cancers. But they increase the risk for breast and cervical cancer slightly.

“The only population that should be concerned about taking the pill is women who are at a very high risk of cancer, such as those with a BRCA mutation,” Bevers says. “They should talk to their doctor about the risks and benefits of the pill.”

Hormone replacement therapy

For women past reproductive age, replacing declining hormones can alleviate some of the unpleasant symptoms of menopause. But hormone replacement therapy (HRT) can raise a woman’s risk for breast cancer and possibly ovarian cancer. There are safer ways to reduce the symptoms and maintain your health.

Talk to your doctor about non-hormonal alternatives for treating menopause symptoms. Those alternatives should be your first choice, she says.

Diet

Soy foods get a bad rap. But there’s not enough data to suggest that the plant estrogens in soy foods, like tofu and miso, increase the risk for breast or other cancers. In fact, soy may have a protective effect.

“Soy is a plant estrogen. We really don’t know the benefits and harms as they relate to cancer risk,”Bevers says. She points out that women who have diets high in soy, like in Eastern cultures, don’t have a higher risk of breast cancer.

And soy products are a good source of plant protein. Plant proteins make a healthy substitute for animal proteins.

“What I typically tell my patients is that a couple of servings of soy a day is okay,” says Bevers.

Endocrine disruptors

Bisphenol-A, or BPA, is a common chemical used in many plastic products and some aluminum cans that mimics estrogen. It sits on a list of chemicals known as endocrine disruptors, due to their effects on hormones. But more research is needed to determine the risks.

“I don’t tell anyone to limit anything in regard to endocrine disruptors,” Bevers says.  “We need more data, in my opinion.”

If you have concerns, try using one of the many alternatives to the plastic products with BPA.

“For people who do have a concern, glass containers make an easy substitute for plastic,” Bevers says.

Chronic inflammation and obesity

Inflammation and obesity go hand-in-hand, and they both have an impact on hormones and cancer risk. Carrying too much body fat causes inflammation. Inflammation increases the amount of both insulin and estrogen in the body, which triggers cell division. Excess fat itself also produces estrogen.

“Over time, the stress that obesity puts on the body by triggering inflammation and increasing hormone levels poses a significant cancer risk,” Bevers says.

Following the general guidelines for a healthy lifestyle goes a long way in regulating hormones and reducing cancer risk.  Maintaining a healthy body weight, eating a healthy diet and staying active help keep hormone levels in check.