Feature

Time to take prevention seriously

As the incidence of breast cancer in the UK continues to rise, a national strategy to tackle its causes is long overdue, argues Laura Potts

Treatment and care for women with breast cancer has undoubtedly improved over the last decade — but there are still more women than ever getting the disease. The UK incidence has exceeded 40,000 cases a year, according to Cancer Research UK.

Making this announcement in June last year, Professor Jack Cuzick, head of Cancer Research UK’s epidemiology, mathematics and statistics department at the Wolfson Institute for Preventive Medicine in London, commented: ‘We need to do more to understand the risk factors and develop preventive strategies’.

But there is little consensus on what preventive strategy is required, and nothing remotely resembling a national policy for primary prevention. Developing such a policy is a real challenge for the public health community: it demands a broad, multiagency approach, and a willingness to listen to the often conflicting views of scientists working in this area.

The ‘prevention’ of breast cancer has tended to be addressed solely in individualised terms: a woman may be assessed as being in a high-risk category on the basis of inherited traits (BRCA1 and BRCA2), familial patterns or her own personal history and characteristics (such as early onset of periods, or never having been pregnant). Yet such ‘risk factors’ are usually outside the control of an individual woman; furthermore, the interventions available, such as prophylactic mastectomy or chemo-prevention, are crude and health-threatening in themselves.

In health promotion terms, we are still ‘blaming the victim’ for her cancer. One woman told us during a recent research project: ‘I find it almost offensive — offensive to think that you could have avoided it “if you’d done this”. For women in that position, offensive is the only word you can use. They’re struggling enough with the aftermath of surgery without thinking they’re responsible for it.’¹

Other countries, such as Canada, are beginning to devise public policies for genuinely primary prevention. They recognise that while traditional secondary interventions, such as mammography or breast self-examination, may (or may not, depending on the research you read) have contributed to earlier diagnosis and to better prognoses, they have done nothing to address the causes of the disease and to prevent women getting it in the first place.

And while much of the advice on preventing cancer generally — such as a healthy and vegetable-rich diet, drinking moderately, taking exercise and not being overweight — may help prevent breast cancer, there is a need to recognise the role of oestrogen in many breast cancers.

Several of the factors known to increase a woman’s lifetime risk of developing breast cancer are related to the metabolism of oestrogen. And while this may sound simply medical, there is now considerable evidence to suggest that many factors in the environment may also be implicated.

So while a recent study established that the use of HRT is associated with a raised risk of developing the disease, there is a huge range of other exposures that mimic the effects of oestrogen in the body and so are implicated in the aetiology of the disease.² Dr Annie Sasco of the WHO’s International Agency for Research on Cancer, based in Lyon, France, gave a presentation on causes and prevention of breast cancer to the Britain against Cancer conference in October 2003. She cited two particular concerns: the use of growth promoters in animal production, and pesticide residues in food.

The International Summit on Breast Cancer and the Environment in California in 2002 also expressed concerns about a group of chemicals called PCBs, and about agents used in plastics, which share the ability to mimic oestrogen in the body.

Protecting women from exposure to such hazards could contribute significantly to a reduced incidence of breast cancer, and to the personal, social, physical and emotional morbidity it brings.

Such measures would also improve the health of others. Some male cancers are hormonally triggered or dependent: agricultural workers using pesticides regularly experience health effects; the effects of ‘gender-bending’ chemicals on wildlife have long been reported; and chemical sensitivity is implicated in many other instances of chronic human ill-health.

The work of the breast cancer and environment movement has been central in moving the agenda for primary prevention and health protection forward. In the US, activists in the Bay area of California have worked with epidemiologists in innovative community participation research projects investigating patterns of local breast cancer incidence. And in the UK, a multidisciplinary forum, Stopping Breast Cancer Before it Starts, was held at the House of Commons in November 2000, sponsored by MPs Alice Mahon and Dennis Skinner. The forum was organised by the Women’s Environmental Network, and chaired by Jane Stephenson from the UK Breast Cancer Coalition.

Epidemiologist Professor Klim McPherson spoke of the need for a national infrastructure to support the necessary implementation and advocacy processes required by a primary prevention of breast cancer strategy. And Professor Charles Coombes, of Cancer Research Campaign Laboratory, asked: ‘When you’ve done the thing of preventing obesity, reducing alcohol and eating more fruit and vegetables, what is there left to do other than make efforts to reduce the carcinogens that surround us?’

Helen Lynn, health coordinator of the Women’s Environmental Network, cited the NHS Cancer Plan’s emphasis on the fundamental importance of prevention, suggesting that collective public health measures, as well as individual behaviour change, would contribute significantly to achieving this goal.

A meeting of the all-party parliamentary group on breast cancer, in January 2002, agreed the need for a working group to establish a public health context for the primary prevention of breast cancer — in Parliament (ensuring joined-up work between departments with related responsibilities), among breast cancer charities and support groups, and among the wider public.

The Economic and Social Research Council’s ‘science in society’ programme is currently funding a project that explicitly aims to establish productive dialogue between the various interest groups concerned with environmental risk of breast cancer.³

Cancer prevention was a key theme of the annual Britain Against Cancer conference in October 2003, organised by the all-party parliamentary group on cancer. One of its plenary recommendations was the promotion of strategies for protection from environmental hazards. Two action points were made:

• to fund and support further research and development into the role of endogenous and exogenous hormones so as to reduce the incidence of breast cancer;
• to reduce potential environmental hazards by tighter regulation and better application of the precautionary principle.

There is now an urgent need for a working group to initiate a primary prevention policy for the UK, which will ‘harness the power of a number of brains’, as one public health director said, ‘since we know so little about the causes of breast cancer’.

Public health, health promotion, environmental health, occupational health and health protection are all disciplines with an honourable tradition of working to improve the conditions in which we live. After all, ‘what if the public health movement [in the 19th century] had directed its efforts not at improving the water supply, but at getting individuals to boil their water and just say no to unboiled water? What if public health workers had spent their money on figuring out which arm of which chromosome holds the gene for susceptibility to cholera? I have no idea what individual, cellular or internal factors account for variations in susceptibility to cholera, and I don’t care. I opt for a safe water supply’ (Barbara Katz Rothman, 1998).

We need to start thinking of breast cancer as, in part at least, a preventable disease and working together towards a national strategy.