Most women treated for breast cancer have something else in common: they worry about the cancer coming back.
Michelle Shayne, M.D., a breast cancer specialist and genetics expert at the Wilmot Cancer Institute, recently spoke to a packed house at the Breast Cancer Coalition of Rochester on reducing the risk of recurrence. She covered a range of topics — from exercise and diet to plastics and hair dyes — and suggested that all survivors should read, ask questions and stay up to date on prevention strategies, even when the data is inconclusive.
“We never want this to happen to us again,” she told the audience.
Here are Shayne’s key messages on each topic:
- “THE ENVIRONMENT” — Studies show that 90 percent of breast cancers are environmental in origin, but the main “environmental” cause is unknown. The environment includes lifestyle (diet, exercise or lack thereof, and smoking, for example), indoor and outdoor toxins, and consumer products and packaging. The good news: most people have some control over their environment and can learn how exposures might contribute to risk, Shayne says.
- AGE — Risk of recurrence is more a function of tumor biology than age. “By and large, younger patients tend to have more aggressive tumor types,” Shayne says. “And cancers in older patients tend to be more slow-growing.” But there are many exceptions, she adds, and each patient must be treated according to her own risk factors, genetic profile and tumor characteristics.
- ALCOHOL — The majority of studies for two decades has shown a link between alcohol consumption and breast cancer risk, although most of those studies do not address a recurrence risk. “Every patient should know about this association,” Shayne says. “But I never tell people what to do. I just bring it to their awareness.”
Research shows: alcohol changes DNA and increases circulating levels of estrogen, regardless of menopausal status, which may increase estrogen-sensitive cancers. If a woman chooses to drink, the suggestion is to consume less than three drinks a week. The type of alcohol does not influence risk.
- ASPIRIN/NSAIDS — Studies suggest that taking aspirin or over-the-counter medications such as ibuprofen might reduce cancer risk by limiting inflammation and aiding in cancer cell death. The problem, Shayne says, is that no details on the dosage are known, and aspirin can cause bleeding complications. “I tell my patients: ‘If your primary care physician advises you to take aspirin for other reasons, you may get an extra benefit for breast cancer prevention.’ ”
- EXERCISE —“Think of exercise as your medicine,” Shayne says. “That way, you’re less likely to say: ‘It’s sleeting, it’s already dark at 4:50 pm, and I don’t want to go to the gym.’” The American Society of Clinical Oncology (the largest organization for oncologists in the world) recommends that after a diagnosis of any cancer, a person should be exercising 150 minutes a week, or about a half-hour a day, five days a week.
Shayne emphasizes that “150 minutes should be the bare minimum.” Brisk walking counts, and cardio exercises are best. Exercise helps to control insulin and may lead to less fat tissue, where estrogen resides. This is important because many breast cancers are fueled by estrogen. Research shows: physical activity after diagnosis may reduce the risk of death from breast cancer.
- DIET — May account for at least 30 percent of all cancers in Western countries. The Mediterranean diet may be best to reduce the risk of breast cancer recurrence, but this is an ongoing and complicated area of research; it often relies on people to report their own food intake. “We also have to be careful to not be looking for a single magic bullet,” Shayne says. “We don’t want anyone to think: ‘If all I do is eat this way, I’m good!’ ”
Research to date shows: a plant-based diet (low or no red meat and plenty of extra virgin olive oil) is associated with a 62-percent relative lower risk of breast cancer compared to women not following a Mediterranean diet.
- SOY — Research is complicated, inconsistent and inconclusive. Shayne says she did an exhaustive search of the scientific literature and did not find any data to support a link between natural soy and an increased risk of breast cancer. However, she recommends avoiding soy supplements and processed soy. Read food labels; processed soy protein is often a primary ingredient in protein bars, cereals, and other packaged foods.
- SUGAR — It spikes insulin levels, and the theory is that since insulin is a growth factor, higher insulin levels may contribute to cell growth and possibly cancer cell growth. Research shows a link between diets with a high glycemic index and risk of breast cancer, regardless of menopausal status, alcohol intake, and physical activity. But the general concept that “sugar feeds cancer” is not useful, Shayne says. Tumors can exist without glucose, and even if a woman removes all sugar from her diet, the body will make sugar from other sources such as proteins and fats.
Shayne suggests: No need to eliminate all sugar or all carbohydrates, but avoid sugary/carbonated beverages and fruit drinks. Choose naturally occurring sugars in fruits and vegetables, and complex carbohydrates containing whole grains. Consuming fiber and protein along with sugar limits the production of insulin.
- ORGANIC FOODS — Beware of products labeled “natural,” “pesticide-free,” and “hormone-free,” which does not mean they are organic. A product labeled “organic” is 95 percent or more organic ingredients. Not enough high-quality studies have been performed to support improved health for consumers of organic foods and products, Shayne says, and safety information for organic foods is lacking. She leaves the buying choices up to her patients. Because of the higher cost of organic foods, some breast cancer survivors give priority to animal fats (meat/poultry, milk, eggs).
- VITAMIN D — “Moderation, moderation, moderation,” Shayne says, regarding vitamin supplements. The tendency in cloudy western New York is to boost vitamin D levels in breast cancer patients, but Shayne notes that it accumulates in fat cells and can be toxic in higher amounts.
- CHEMICALS IN FRAGRANCES — FDA banned these chemicals from foods but they are still used in fragrances: styrene, benzophenone, ethyl acrylate, methyl eugenol, myrcene, pilegone, and pyridine. Manufacturers are allowed to withhold fragrance ingredients to protect trade secrets. “There are many unknowns when it comes to fragrance,” Shayne says.
- HAIR DYES — A tricky subject and a personal choice, Shayne says. Some facts to consider: The FDA banned lead acetate (linked to neurotoxicity) from hair dyes in 2018; more than 5,000 different chemicals are used in hair dye products and some have been linked to cancer in animals, according to the National Cancer Institute; but personal use of hair dyes is not classifiable as carcinogenic to humans, according to the International Agency for Research on Cancer. Darker hair colors contain a chemical known as PPD (para-phenylenediamine), made from coal tar, a petroleum derivative that contains other harmful chemicals. The greatest risk may be to hairdressers due to constant exposure.
- PLASTICS — Contain chemicals that should be avoided. If recyclable packaging is labeled with the numbers 3, 6, or 7, it may contain carcinogens and hormone-disrupting chemicals, which can boost estrogen levels. Check the numbers on the bottom of sports bottles, water bottles, and food containers. Keep plastics away from heat (including sunlight and inside hot automobiles) to prevent the chemicals from leaching into food and drinks. Avoid reusing plastic containers intended for single use. The safest choices are labeled with the numbers 2, 4, 5.
- PARABENS, PHTHLATES, PETROLATUM — Used in thousands of personal care products, foods, pharmaceuticals, packaging, and plastics. Each has an association with genes or hormonal activities in the body that are linked to breast cancer, although further research is required. Shayne has a particular concern with parabens, which can stimulate breast cancer cells.
“When something says ‘No Parabens’ it speaks to us,” she says. “Any paraben in any form should raise a level of concern.” (Listed on labels as methylparaben, ethylparaben, propylparaben, butylparaben, isopropylparaben, isobutylparaben.) It is less clear to what extent phthalates and petrolatum contribute to cancer in humans, but they affect estrogen production and can disrupt hormonal balances.
- ANTIPERSPIRANTS — “There are some provocative observations that lead us to wonder if there’s a relationship to breast cancer,” Shayne says. For example, a disproportionately high incidence of breast cancer is found in the upper, outer quadrant of the breast, along with genomic instability in the cells near the underarm. Aluminum chlorhydrate is the active ingredient in antiperspirants, and aluminum is known to cause gene toxicity by altering DNA. But the data is inconclusive when it comes to antiperspirants and breast cancer.
- SUNSCREEN — FDA is actively investigating sunscreens, Shayne says, due to concerns about the chemical ingredients that accumulate in the body with continual use when sunscreens are reapplied, as directed. There is no evidence currently that sunscreens are harmful; Shayne says women must balance the risks of sunburn and skin cancer against the risks that chemicals might pose to a breast cancer recurrence.
Sunscreens based on zinc oxide and/or titanium dioxide are generally regarded as safe and effective; they’re not absorbed into the body but act to reflect the sun’s harmful rays by sitting on the skin. Shayne says zinc oxide is her personal preference.