Breasts. Kristi Funk, M.D.

odor-eating deodorants are at play.

      While we’re talking chemicals, let’s move on to hair relaxers, particularly those feared to cause cancer in African American women. No doubt about it: cancer-causing compounds abound in hair products, but luckily for African American women who sport straight and silky hair, hair relaxers don’t make a cancer connection. Hair relaxers or straighteners, in the form of lotions or creams, chemically straighten curly hair by altering the hair’s internal structure. Product ingredients can enter the body through scalp burns or open cuts and sores. Since millions of African Americans use relaxers to reduce curl—one study found that 94 percent of African American women surveyed under age forty-five had used them at some point in their lives—these products have become the subject of much scrutiny, particularly as they may or may not relate to causing breast cancer.²⁵ Funded by the National Cancer Institute (NCI), researchers followed over 48,000 African American women for six years in the Black Women’s Health study.²⁶ A number of parameters were evaluated with respect to health and habits. Participants included women who had used hair straighteners seven or more times a year for twenty years or longer. When analyzing the 574 new cases of breast cancer that occurred during the study, researchers could not find any association between breast cancer risk and the duration of hair relaxer use, frequency of use, age at first use, number of burns experienced during use, or type of hair relaxer used.

      Perhaps what we should be focusing on isn’t straighteners specifically, but the fact that there are numerous and potentially cumulative health hazards hiding in our self-care products—particularly in African American communities. Specifically, hair products, including shampoos, conditioners, oils, dyes, relaxers, and root stimulators, containing estrogens and placental extracts can mimic estrogen in our bodies so much that use of these hair products in early life has been considered a major contributor as to why the proportion of girls at age eight who experience early puberty (precocious puberty) is nearly four times greater for African Americans than for whites (48.3 percent and 14.7 percent, respectively).²⁷ Check hair product labels and avoid using ones that contain estrogens, other hormones, and placenta, particularly for young children or while pregnant.²⁸

      PIERCINGS AND TATS

      If you’re worried about the nipple piercings and body tattoos you got during your punk phase in college, let me put your mind at ease. Nipple piercings don’t cause breast cancer. Studies show that nipple piercings can cause breast infections, or theoretically create difficulties with breastfeeding, but they don’t cause breast cancer.²⁹

      Tattoos also can cause infection and allergic reactions; sterile needles and uncontaminated ink minimize that risk. Unlike piercings, tattoos fall under the “not sure, probably fine” cancer category. Studies show that skin cancers do not occur any more frequently than would be expected at the location of a tattoo,³⁰ which should reassure breast cancer patients recreating a 3-D–appearing nipple and areola on mastectomy skin, or tattooing makeup in anticipation of chemotherapy-induced eyebrow and eyelash loss. On the other hand, when I remove lymph nodes during a cancer operation on someone with upper body art, the pathologist usually identifies tattoo pigment trapped within a node or two because the skin lymphatics drain ink to that location. No reports find that tattoos increase breast cancer risk, or that nodes with ink are more likely to contain metastatic breast cancer; however, ink does contain phthalates, hydrocarbons, and a number of other potential carcinogens and endocrine disruptors,³¹ which, as part of a larger whole, possibly impact breast cancer risk (see chapter 5). For mastectomy patients who worry about FDA warnings to “think before you ink,” pretty real-looking silicone reusable nipple prostheses come in a shade that matches skin tone; they just stick in place. An option: pinklotus.com/adhesivenipple.

      RADIATION REBUKES

      In our increasingly tech-reliant world, a lot of patients worry about radiation affecting breast cancer risk—specifically from mobile (cell) phones and power lines. Based on the studies available, this doesn’t appear to be a concern. Phew.

      In 2018, the number of mobile phone subscriptions (6.8 billion) approached the number of people on Earth (7.5 billion). Since these devices emit radio-frequency (RF) signals and electromagnetic fields (EMF), their ubiquity has generated public concern over possible adverse health effects. The real controversy centers on cell phone use and the risk for brain cancer, but breasts have a way of getting attention too.

      From what we can tell, mobile phones can’t cause breast cancer, even if you tuck them in your bra, because they do not emit the right type of energy (or a high enough amount of energy) to damage the DNA inside breast cells. In order to communicate with service towers, cell phones emit EMF. Body tissues absorb some of this radiation during regular phone use; usually those nearby tissues would be your face and brain, not your breast, but in the quest to be hands-free, many women tuck that smart box into a bra or shirt pocket. Here’s the key concept: mobile phone EMF is nonionizing, and as such, the energy waves are too wimpy to break DNA and other biochemical bonds. Besides your phone, other nonionizing sources of radio-frequency signals include microwaves, television, radio, and infrared.³²

      In contrast to nonionizing EMF, X-rays, gamma rays, and ultraviolet (UV) radiation emit ionizing EMF. These do create enough energy to mutate DNA, which can potentially lead to cancer. Common ionizing sources include sun exposure (UV rays) and medical X-rays like CT scans and mammograms. For a cell phone’s energy to go from nonionizing to ionizing, it would have to get 480,000 times stronger than it currently is.³³

      Several notable studies have examined the cell phone/cancer connection as it relates to brain tumors.³⁴ Only one of these authors observed an increase in brain tumors with the use of mobile phones, and all the other studies could not reproduce the correlation.³⁵ No study has postulated that cell phones cause breast cancer. If you carry your phone in your bra, I’d be more concerned about accidentally texting a photo of your breast to your boss than causing cellular damage to your breast DNA.

      Living near power lines can’t cause cancer either. Power lines emit both electric and magnetic energy that’s too muted to damage breast DNA. Additionally, walls, cars, and other objects shield and weaken the energy from power lines. When rates of female breast cancer on Long Island ranked among the highest in New York State, a 2003 study set out to explain possible environmental reasons why.³⁶ One theory was that EMF caused the hike in cancer. Rather than using indirect measurements of EMF exposure (such as occupation or distance from power lines), investigators performed comprehensive in-home assessments of magnetic field exposure and only looked at women living in the same home for at least fifteen years. They compared these data between almost six hundred local women with and without breast cancer; in the end, they found no link between the disease and EMF emitted by power lines. A nationwide Finnish study and a Seattle-based study also concluded that typical residential EMF generated by high voltage power lines do not elevate overall cancer risk in adults.³⁷

      Similar to the EMF from cell phones, magnetic energy from power lines produces a low-frequency, nonionizing form of radiation that doesn’t mess with the breast. Maintaining that the weak EMF derived from power lines could have a catastrophic biologic effect sounds plausible to most of us because we don’t readily understand physics; but to a physicist, it’s a laughable proposition.³⁸ Consider this factoid: the magnetic field from the earth itself is 150 to 250 times stronger than ones from power lines. If a power line’s small magnetic field could cause breast cancer, then just inhabiting Earth for a few years should lead to a total body cancer transformation.

      HORMONE-RELATED HEALTH WORRIES

      A lot of women express concern that certain health habits increase their risk—most of which circle the topic of affecting their estrogen levels, since estrogen feeds the majority of breast cancers. However, a bunch of these worries are, in fact, myths.

      I’ve repeatedly heard the popular rumor that oral contraceptive pills (OCP)—birth control pills—cause breast cancer. But if you are at normal risk for breast cancer, an unexpected pregnancy will add a lot more worry to your