Enough is known about the causes of breast cancer to make a vaccine or prophylactic drug a real possibility, a leading cancer expert said this week.
Professor Valerie Beral, who leads the Million Women's Study into the causes of the disease, said the study had put beyond doubt what had long been guessed - that many breast cancers are caused by the absence of hormonal changes connected with childbirth.
Prof Beral challenged the scientific community to turn its efforts to preventing breast cancer saying that while money and effort is poured into better drug treatments, hardly anyone is working on prevention.
In an interview, she said that while death rates have been slashed by new drugs and earlier diagnosis, the number of women getting breast cancer and having to go through traumatic surgery and chemotherapy is rising.
Professor Beral said genes played a part in only a very small number of cancers. The processes of giving birth and breastfeeding protected a woman from breast cancer more than anything else.
The more children a woman had and the longer she breastfed, the lower her risk was of later contracting breast cancer. Women in developed countries where small families are the norm have six times the breast cancer risk of those in rural parts of Asia with large families.
But returning to an era where women had endless babies and breastfed for two years or more at a time was not an option, said Prof Beral.
"But why aren't we thinking of mimicking the effects of childbirth?" she said. "We don't know how this happens and nobody is doing research on it. We should be looking at hormone production during late pregnancy and lactation."
Prof Beral is director of the cancer epidemiology unit of England's Oxford University. Her work uses large amounts of statistical data to identify the traits or behaviour that put women at risk of breast cancer.
She is not a biochemist, but she asked the National Cancer Research Institute's annual conference last week why the avenue of breast cancer prevention which might lead to a drug or vaccine was not being pursued. It has already happened in cervical cancer, she pointed out.
The interaction between the hormone surges around childbirth and breastfeeding and breast cancer is not simple.
Oestrogen, the hormone which surges in pregnancy, fuels tumour growth. Many women with breast cancer are given drugs to stop oestrogen production.
In Bahrain this year's Think Pink campaign has been launched this month to raise awareness of the disease and money to help sufferers.