Photo of a breast self examination
Self examination is a good way to catch breast cancer early

Breast cancer and the environment

19 February, 2013

Breast cancer is the leading cancer killer among women aged 20-59 years in wealthy nations, and annually, is responsible for around half a million deaths worldwide” — World Health Organization

We live in a toxic world.

In the UK around 31,000 tonnes1 of  ‘active ingredient’, the chemicals at the heart of the £500 million British pesticides industry, are used each year. Nearly 80% of the pesticides used in England and Wales are used in the agricultural and horticultural industries; the rest used in gardens, homes, forestry and amenity uses (public spaces, pavements and railway lines etc).2 Over the last 10 years, 37 pesticides have been banned in the UK.3 Of the 311 pesticides commonly still used, 150 have been identified as potentially causing cancer.

Organophosphate pesticides, the most hazardous pesticides to vertebrate animals according to the World Health Organization, were banned for most residential uses by the European Protection Agency in 2001; however they are still used in UK agriculture.

A similar picture in the US
In the US more than 80,000 synthetic chemicals are registered for use by the Environmental Protection Agency (EPA) today, though there is no clear data of how many are actively still in use, or how safe they are.

In fact, when the Toxic Substances Control Act (TSCA) was passed in 1976, the 62,000 chemicals in use at that time were approved without safety reviews, simply because they were already in use. The TSCA has never been updated, which means that companies in the US are allowed to manufacture and use chemicals without establishing their safety.

Currently regulation is so weak that only an estimated 200 of the 80,000 registered chemicals have ever been tested for safety in humans,4 and of the almost 3,000 HVCs (High Volume Chemicals) manufactured or imported at over 1 million pounds per year in the US, 93% do not have a full set of toxicity data.5

The chemical influence on cancer

As the use of chemicals has risen in the US and other industrialised countries, so have rates of breast and other cancers. Research confirms that environmental factors can directly lead to cancer, but unfortunately, proving harm from exposure to chemicals in the environment is challenging.

The time between exposure and development of disease may be decades. We are unlikely to know exactly which chemicals we’ve been exposed to, and we’re not exposed to chemicals in isolation.

Even when chemicals are banned they may continue to exist in the environment, in soil or by polluting water sources, and the effects of exposure can continue for many years. The pesticide DDT was banned in the USA in 1972 (and the UK in 1984), but was detected in soil samples nearly 30 years later.6

Most recently, a comprehensive new report  from the World Health Organization, paints an alarming picture of the threat to human health. It concludes that hormone disrupting chemicals such as include diethylstilboestrol (DES), polybrominated diphenyl ethers (PBDEs), benzopyrene, bisphenol A, lead, arsenic, cadmium and methylmercury are ubiquitous worldwide and implicated in fertility problems in both men and women, developmental problems in children and even hormone related cancers.

What we don’t know will hurt us

If only it were as simple as choosing not to come into contact with potentially unsafe chemicals. Consumer product labels are often misleading or incomplete. Manufacturers are not required to list all ingredients on cleaning product labels; and ingredients in “fragrance”, which can be numerous, are considered a “proprietary blend” and therefore kept secret. To make things even more confusing, there is very little regulation over claims such as “gentle”, “safe”, “natural”, or “non-toxic” in US product labelling.

Adding these factors to the invisible synthetic chemicals all around us, fire-retardants on sofas, formaldehyde-releasing resins on ‘non-iron’ fabrics, plasticizers in our water bottles, pesticides and genetically modified organisms (GMOs) in our fruit and vegetables, we are simply surrounded by hidden toxic hazards.

Breast cancer risk factors

Known risk factors for women include: family history; not having children or having children later in life, early menstruation, late menopause, post-menopausal obesity, hormone therapy (aspects linked to levels of estrogen; and lifestyle factors such as alcohol consumption, exposure to second-hand cigarette smoke and fitness levels. Studies show the risk associated with oral contraceptives appears small, and diminishes when no longer used.7

Yet the majority of women diagnosed with breast cancer appear to have none of the known risk factors, which means that the causes are as yet unknown. Research indicates that environmental causes may play a role in 30-50% of unexplained breast cancer cases.8

Estrogen and endocrine disruptors

High levels of estrogen (a hormone secreted primarily by the ovaries, regulated by the endocrine system) have been linked to breast cancer. Many personal care and cleaning products contain ingredients reported to interfere with endocrine function. Several man-made chemicals also mimic the effect of estrogen in our bodies, including parabens (found in many personal care products), BHA (Butylated hydroxyanisole – a food preservative), and BPA (Bisphenol A – a component of some types of plastic, often used to line cans).

Simple things you can do

Educate yourself Learn about the ingredients to avoid, and read the labels on everything you buy. Many non-profit organisations are making it easier to select safer products (see sidebar).

Know your body Check your breasts monthly. Learn what is normal for you and pay attention to any changes. If you find a change, or have any concerns, talk to your doctor. For information on how to conduct a self breast exam see here.

Keep active Regular exercise can help reduce estrogen levels thereby reducing risk of developing cancer, and studies show that women with higher aerobic fitness are also less likely to die from breast cancer.

Watch your weight Extra pounds are never good for our health, but after the menopause extra weight increases the risk of developing breast cancer for women by acting as a significant source of estrogen.

Look for the organic certification (e.g. Soil Association/USDA) on produce Washing non-organic fruits and vegetables doesn’t always help, because some plants absorb pesticides systemically. If you can’t find organic produce, visit the Pesticide Action Network’s guide to the best and worst foods for pesticide residues, here. Alternatively check out the Environmental Working Group’s Dirty Dozen list of the most heavily sprayed crops to avoid, here.

Get informed Here’s some great books to start you off: Living Downstream by Sandra Steingraber, Silent Spring by Rachel Carson, and Exposed by Mark Shapiro. Films about related issues include Food, Inc., Last Call at the Oasis, Pink Ribbons Inc., and Unacceptable Levels. Breast Cancer: an Environmental Disease, produced by the UK Working Group on the Primary Prevention of Breast Cancer, is available to download here. The Breast Biologues, an award-winning animated video, explains how the normal breast develops and how exposure to potential cancer-causing chemicals may influence future breast cancer risk.

Stay current Sign up for the Source, Breast Cancer Action’s newsletter  and for the Breast Cancer Fund’s e-alerts.

Act for change Insist on policy reform, stricter regulations, and full disclosure of ingredients on product labels. Follow organisations demanding change and sign petitions – they are effective (see sidebar).



1 Soil Association, “What are the problems with pesticides

2 Environment Agency Wales, 2007 Pesticides Report.

3 Pesticides Action Network UK, Pesticides in Your Food.

4 State of the Evidence: The connection between breast cancer and the environment, Gray J, 2010. (6th ed). Published online by Breast Cancer Fund.

5 Chemical Hazard Data Availability Study / What Do We Really Know About the Safety of High Production Volume Chemicals?, EPA Office of Pollution Prevention and Toxics April 1998

6 Toxics use reduction in the home: lessons learned from household exposure studies, Dunagan, SC et al, J Clean Prod, 2011; 19(5): 438-44.

7 Breast Cancer and the Environment: A Life Course Approach, Institute of Medicine of the National Academies, 2011.

8 Migration patterns and breast cancer risk in Asian-American women, Ziegler RG, et al, J Natl Cancer Inst 1993; 85: 1819-27.