Feature

Hidden dangers on home ground

Screening programmes have their place – but where is the research and action on the causes of breast cancer? Laura Potts reports on how women’s groups are initiating their own research

This summer, the controversial findings of the Canadian preventive health care task force were published in the Canadian Medical Association Journal, generating considerable media interest in the UK, as well as in north America.¹

The research claimed that breast self-examination is ineffective. ‘There is fair evidence of no benefit and good evidence of harm’, it says, referring to the risk of unnecessary biopsies of suspicious lumps, leading to disfigurement and emotional distress, and of unnecessarily raised anxiety. Health authorities are now wondering whether to stop recommending that women examine their own breasts.

Michael Baum of University College London, one of the UK’s leading breast cancer surgeons, was quoted in The Observer as saying ‘this study is terrifically liberating news for women’, echoing the research recommendation that women should attend regular mammography screening as their best bet for early detection of breast cancer. But, of course, this is only available to, and advisable for, women aged 50 to 69.

Unfortunately, the controversy generated by the Canadian research obscures the fundamental public health issue: why is the incidence of breast cancer continuing to rise? What can be done to prevent women getting the disease? What might genuinely ‘liberate’ women from the threat of this all-too-common cancer?

Detection and diagnosis are, of course, important and should, as the UK Breast Cancer Coalition Plan emphasises, be uniformly and reliably accurate and effective. But the primary prevention of the disease is still neglected by policymakers. The NHS Plan talks about individual lifestyle changes – diet, exercise, smoking, alcohol consumption – in relation to cancers generally. And although it mentions that some cancers may have environmental causes, it does not propose any action to tackle them.

Genetic screening for women with an inherited ‘high risk’ of developing breast cancer still tends to dominate popular media reports, with the result that most women believe that the genetic (BRCA1 and BRCA2) causes of the disease are far more common than they really are – around five per cent of all breast cancers.

Risk assessment and risk management have become central to all aspects of public health policy but are frequently either individualised, so people become isolated with personal health worries, or generalised, so groups of, for instance, perimenopausal women are inappropriately assumed to share characteristics and lifestyles.

Breast cancer activists in the UK and the US are challenging these limited ways of thinking through research that is investigating the environmental histories of communities with a high incidence of the disease. Women from Long Island in New York state have just been awarded a federal grant to continue their study, which is demonstrating how the contamination of the community with toxic chemicals is implicated in the numbers of women with breast cancer. Similar work in the Bay Area of California, which has one of the highest incidences of the disease in the world, is trying to identify specific environmental factors that may be implicated.

A collaborative project has also been established in Marin County, where the incidence in white, non-Hispanic women aged 45 to 64 is even higher than in the rest of California. Marin Breast Cancer Watch, a grass-roots, activist organisation, is working with a newly set up epidemiology unit in the Department of Health and Human Services, to map the past 25 years of breast cancer cases in the county.

In the UK, the Women’s Environmental Network (WEN) has funding for a new project called ‘Women Taking Action for a Healthier Planet’. The aim is to further develop the work started in the previous project, ‘Putting Breast Cancer on the Map’ (see healthmatters issue 35), which invited women to map their local area and plot any information they had about breast cancer prevalence.

Since breast cancer can take many years, and perhaps even decades, to develop some of this research has to be retrospective, insofar as it relates to a current pattern of disease distribution, looking at old records and memories in a locality. The work is further complicated by the fact that many women have moved around the country in the course of their lifetime, so carcinogenic exposure 15 years ago may not relate to the current place of residence.

But these issues mean that we are having to develop a different model of epidemiological inquiry, one that validates women’s knowledge and experiences, and extends the notion of lay research. It also needs to recognise that communities at greatest risk have most at stake, so they should be given the lead voice in developing a prevention strategy. In Marin County, researchers are using oral history methods to help collate a complete picture of the pattern and causes of breast cancer over time.

In terms of current environmental risk factors, there is growing evidence on certain substances which are implicated in breast cancer development (see WEN’s information booklet for ‘Putting Breast Cancer on the Map’ and Health Matters issue 35 for more details). Chemicals that mimic the action of oestrogen in the body or disrupt the body’s endocrine balance are of particular significance.

Pesticides, both domestic and agricultural, hormones in food (such as bovine growth hormones), hormonal drugs (for contraception or as hormone replacement therapy) and plastics (such as phthalates and vinyl chloride) are among the chemicals to which we are exposed daily – all known carcinogens with particular affinity for breast cancer cell development.

In the UK, agricultural pesticides are regulated by the Pesticide Safety Directorate, part of the department of the environment, food and rural affairs; non-agricultural pesticides are registered by the Health and Safety Executive, which now comes under the department for transport, local government and the regions; responsibility for public health, health promotion and disease prevention lies with the department of health.

Clearly, any strategy for reducing the environmental risk of breast cancer requires a fully integrated and coherent framework of collaboration across government, as well as recognition of expertise in non-governmental organisations.

In Sweden, the Breast Milk Monitoring System consistently analysed samples of women’s breast milk for toxic residues, providing a valuable database for future study and, incidentally, revealing how many chemicals persist in the body, years after their use has been phased out.² There is currently no such extensive monitoring of chemical residues in people in the UK, and little government interest in opening the door any wider to include such public health projects.

But many activists in this field would argue that resources would be better directed towards withdrawing those chemicals against which there is significant evidence, and substituting non-toxic or less toxic alternatives wherever possible. This would involve an ideological shift of policy, an acceptance of the precautionary principle (see box) to protect the population from known or suspected hazards.

There is, after all, a long and honourable tradition of this very approach within the public health movement. We may have failed to activate a principled approach in relation to tobacco and to asbestos use, for reasons I am sure are only too obvious to readers, but that should strengthen the case to act with caution now.

The 19th century reformers did not urge early self-detection of cholera, or establish population screening programmes, or bid for research monies to determine genetic pathways of susceptibility. Neither did they invest in high-profit pharmaceutical solutions. Instead, they identified a likely causal link between a health hazard and disease, and took political action to remove the hazard. To stop breast cancer before it starts we need genuine primary prevention, and we need protection from political, chemical, and economic environments that can cause the disease.

In the UK, primary prevention of breast cancer is being addressed by a coalition that includes groups such as ‘Free rrradicals’, campaigning on breast cancer and the environment; the Women’s Environmental Network; UK Breast Cancer Coalition; Breast UK; and the trade union Unison – working under the banner ‘stopping breast cancer before it starts’. To this end, a participatory forum was held in the House of Commons last winter where key speakers from the voluntary sector, occupational and environmental health, cancer research charities, and public health epidemiology all called for dedicated funding for primary prevention.

A working group has now been established to ensure these issues continue to be heard and that public health policy comes to reflect them. The aim is to shift the national policy agenda, encouraging a real joined-up government approach and a new working party between the various departments with a role in protecting the public health, so effective action may follow.