Breast cancer: breaking the chain

As a GP in North London, I see the ravaging effects of breast cancer in young women.

One in nine women overall will develop breast cancer, most in old age. And although it's never great news to be told you have cancer, the older you are when you get it, the better it tends to be. The cancers that younger women get are often more aggressive and difficult to contain. Older women generally die with their cancer, not of it.

Breast cancer affects all types of women, and men. Fewer than ten percent of breast cancers are thought to be due to a genetic fault. But in families carrying a faulty gene, it can blight generation after generation. Dangerous BRCA mutations, for example, can be particularly prevalent in certain communities like the Ashkenazi Jewish community. And it's one of the few diseases that affects richer women more than poorer ones; presumably because richer women tend to have kids later in life.

So given where I work - in a fairly affluent suburban area with a significant Jewish population - it feels like there is an epidemic of breast cancer. The number of women under 50 with breast cancer remains low, but each patient sticks in my mind as their illness traumatises the whole family. Many will be women whose mum, aunt and cousins have had breast or ovarian cancer. But not all; a close friend who died of breast cancer in her 40s, was the first known case in her family.

Many women have their cancers picked up during mammography screening. There is a worrying question about whether some of these early breast cancers, detected only on mammogram, would ever have caused problems if left undetected. The reworded leaflet about the NHS breast cancer screening programme is to be welcomed as it spells out that screening may lead to unnecessary investigations, treatment and anxiety.

There was so much of interest at the Progress Educational Trust's recent event 'Risk Assessment: Breast Cancer, Prediction and Screening', which was supported by the Wellcome Trust and which I chaired. Wendy Watson told her inspirational story about how she fought to have her breasts removed surgically to prevent the breast cancer that was so prevalent in her family. She made this choice way before Angelina Jolie brought the possibility of preventative mastectomy to the public's attention. Wendy gave up being a farmer to run a helpline for people wanting information about inherited breast cancer and to campaign against gene patenting which would make the test very expensive.

Epidemiologist Professor Klim McPherson spelled out that the older girls start periods and the younger they have their first baby, the lower the rates of breast cancer. This is because breast cancer is linked to exposure to oestrogens. A geneticist in the audience even wondered whether girls in families with a genetic predisposition to breast cancer should be given hormone treatment to delay their periods. Others said this raised serious ethical problems.

Statistician Professor Stephen Duffy was confident that screening using mammography saves lives but acknowledged the problems of overdiagnosis and the anxiety it causes. He said we have good risk prediction tools and can offer drugs (such as tamoxifen) to help prevent hormone-dependent cancers developing in high risk women. The problem is that non-hormone-dependent cancers are harder to treat, as we don't understand what causes them and we can't prevent them.

Fertility specialist Paul Serhal offered hope for a way to stop the disease affecting successive generations. If a man or woman carries one of the high-risk BRCA mutations, they can be offered IVF with preimplantation genetic diagnosis to ensure the implanted embryo is free of the faulty gene.

A member of the audience talked about epigenetics: the idea that environmental factors affect the way our genes are expressed. Could a healthy lifestyle stop you developing cancer even if you have an inherited tendency? The answer seems to be yes.

One panellist wondered whether exposure to oestrogen-type byproducts of plastics is a factor in the rise in breast cancer rates. The jury's out on that one but we're likely to hear more about chemicals that have hormonal effects and may trigger breast and other cancers.

Many members of the audience contributed their stories, questions, ideas and views. I learned a lot and was left with a profound sense of admiration for campaigners like Wendy, innovators like Paul, academics like Stephen and Klim and the many men and women who brought their own perspectives to this lively evening.