Breast feeding & breast cancer

Valerie Beral made an interesting claim on this week’s Life Scientific, which I for one have not heard expressed in such clear & simple terms before.

We all know, pretty much, that breast cancer risk increases in line with the age at which a woman has her first child. International comparisons show quite clearly that breast cancer is rare in countries where women bear six or more children, each of which may each be breast fed for as long as two years; on the other hand rates of cancer have risen inexorably in countries like ours, where child birth is postponed & breast feeding quite widely regarded as optional.

Beral went on to translate this into an assertion that even one child, born to a twenty-year-old, conveys a lifetime benefit of a 10% reduction in the risk of breast cancer. This she thinks must be due to one of the hormones of pregnancy (rather than, for example, mere absence of menstruation).

If scientific research could identify that hormone, then we could envisage the development of something akin to inoculation* – perhaps a single injection or dose which could be given to girls in their late teens to convey a comparable benefit.

So why is the necessary research not done? Beral thinks it will need a committed, wealthy backer – just as the original research on The Pill & IVF was done in the private sector.

I am left wondering if the evidence is strong enough to support an estimate of the benefit which accrues even to an older mother who breastfeeds for six months. At least offer mothers some direct personal benefit for all those broken nights.

*On reflection, perhaps vaccination, the word Beral used, is truly more appropriate in this context

Link
Life Scientific: Valerie Beral