Breast cancer risk: what’s breastfeeding got to do with it?

Eliminating risk concept

Two articles on breast cancer risk were published this week and they provide a window on the politics of breastfeeding.

The first paper is Learning, Life, and Lactation: Knowledge of Breastfeeding’s Impact on Breast Cancer Risk Reduction and Its Influence on Breastfeeding Practices.

It received a fair amount of press, including articles like Study finds doctors aren’t telling moms about breastfeeding’s cancer protection:

[pullquote align=”right” cite=”” link=”” color=”” class=”” size=””]Promoting breastfeeding as reducing breast cancer risk is yet another inappropriate attempt to pressure women.[/pullquote]

When it comes to reducing women’s risk of breast cancer, epidemiological studies connect breastfeeding beyond the baby’s first year with a lower chance of developing triple-negative breast cancer.

That news isn’t getting out enough, according to a survey of 724 women from the Ohio State University Comprehensive Cancer Center. It found that although almost 60 percent of breastfeeding mothers knew their risk of cancer was reduced, only 16 percent said they got the news from health care providers.

The lead author, Bhuvana Ramaswamy, apparently a rabid lactivist, had this to say:

“There’s so much effective marketing by Nestle about infant formula,” she added. Hospitals still don’t always support early breastfeeding efforts, she said.

“Often mothers are told, ‘We can room the baby in the nursery, so you can get a good night’s sleep,’” she said. “They’re bottle-grooming the baby at the start.”

Bottle-grooming? Seriously? Are lactivists analogizing bottle feeding to sexual predation now?

What is the magnitude of this reduction in breast cancer risk? According to the widely cited study by Horta et al.:

The largest individual-level analysis on this topic included about 50000 patients with cancer from 47 studies,30 which is about half those included in our meta-analysis. Each 12-month increase in lifetime breastfeeding was associated with a reduction of 4·3% (95% CI 2·9–6·8) in the incidence of invasive breast cancer.

So Dr. Ramaswamy believes that it is imperative to make women aware of a 4.3% decreased risk of breast cancer because it is yet another factor that will convince women to breastfeed.

The second paper that was recently published is Breast Cancer Risk After Recent Childbirth: A Pooled Analysis of 15 Prospective Studies. The authors found:

Compared with nulliparous women, parous women had an HR for breast cancer that peaked about 5 years after birth (HR, 1.80 [95% CI, 1.63 to 1.99])…

Compared with nulliparous women, parous women have an increased risk for breast cancer for more than 20 years after childbirth. Health care providers should consider recent childbirth a risk factor for breast cancer in young women.

As a New York Times article explains:

…[I]n women between the ages of 41 and 50 who had given birth in the previous three to seven years, the study found that 2.2 percent developed breast cancer, while in those who had not had babies, the figure was 1.9 percent.

That’s an increased risk of 16%.

But don’t worry; that risk is still low.

[R]esearchers said that the findings should not influence women’s decisions about if or when to have children.

See the paradox?

Childbirth increases breast cancer risk by 16% in the short term, but that risk should not influence women’s decisions about if or when to have children.

Yet, breastfeeding decreases the risk of breast cancer by 4.3% and women should strongly consider that in making a decision about whether to breastfeed.

On the face of it, these opposing approaches make no sense. Even with a 33% increased short term risk of breast cancer, the actual number of breast cancer cases is so small that it should not be a factor for women in determining whether to have children. Obviously a 4.3% reduction in breast cancer risk as a result of breastfeeding is far smaller still. Therefore, it should not be a factor for women in determining whether or not to breastfeed.

In truth, a woman’s risk of breast cancer is complex and multifactorial and childbearing and breastfeeding are two relatively minor modifiers of risk. But in the world of breastfeeding promotion, any benefit no matter how small is exaggerated and celebrated as a reason to pressure women to breastfeed.

Taken together these studies illustrate how risk is emphasized or ignored based on researchers’ priorities, not based on reality. Promoting breastfeeding as reducing breast cancer risk is yet another inappropriate attempt to pressure women into breastfeeding. If anyone is engaged in grooming, it is lactation professionals who routinely mislead women about the benefits of breastfeeding, elide its risks and remain utterly dismissive of the harm that pressure to breastfeed causes both babies and mothers.