Are city women at more risk of breast cancer?
Publication Date:28/11/2007
Introduction
Women living in London have denser tissue in their breasts, compared to women living in the countryside, a new study has found. Dense breast tissue increases a woman's chances of getting breast cancer, so women living in cities might have a higher risk of this disease, the researchers say.
What do we know already?
Women's breasts are made up of a mixture of fatty tissue and glandular tissue. Glandular tissue includes the glands that produce milk for breastfeeding, as well as supporting tissue. It makes the breasts more dense. As we get older, glandular tissue gets replaced by fatty tissue.
Research has shown that women who have more of the dense, glandular tissue are more likely to get breast cancer, compared to women the same age with less glandular tissue. Scientists are not sure why that is. It may be that cancer is more likely to develop in these glandular cells than in fatty cells.
What does the new study say?
The researchers studied breast scans (mammograms) from women who had been screened at the private Princess Grace Hospital in London. Of these, 225 women lived in the countryside, 135 lived in the suburbs and 257 lived in London.
After studying the scans, the researchers said the mammograms of women living in London were most likely to show denser tissue associated with a higher risk of cancer. But a lot of the difference was because of their age. Women living in London were younger than women living in the countryside or the suburbs. Younger women have more dense breast tissue.
After taking the women's age into account, the study showed women living in London were still about 50 percent more likely to have any dense breast tissue, compared to rural women. But there was no significant difference between women who lived in the suburbs and the countryside.
The research was carried out by doctors from the privately-run Princess Grace Hospital in London. The lead researcher, Dr Nicholas Perry, discussed the results at the annual meeting of the Radiological Society of North America, held in Chicago, USA.
How reliable are the findings?
The researchers' findings have not been published in a medical journal. They were presented to other researchers at a medical conference.
Because the research hasn't been published in a medical journal, we can't check all the figures, or look at the study to see how well it was carried out. We have to rely on what the researchers tell us. Also, before publishing studies, medical journals ask other doctors to look carefully at them to make sure they don't have serious errors. This study hasn't been through that checking process.
The researchers didn't look at whether the women in the study actually got breast cancer. So the study did not prove that women in cities get breast cancer more than women living in the country. It just shows they might be more at risk, because of their type of breast tissue.
What does this mean for me?
If you're a woman living in a city or town, don't panic. The study doesn't mean you are going to get breast cancer. The researchers don't know why women living in London had more dense breasts than women living in rural areas. There might be lots of reasons, and they might not apply to you.
For example, women living in London are much less likely to be overweight than women living elsewhere in the country. Overweight women are likely to have more fatty breast tissue. So the difference in type of breast tissue might be more to do with women's weight and lifestyle, than where they live.
Remember that breast tissue density is just one of many things that affect the risk of breast cancer. Other things, like whether you have had children and at what age, whether you have breastfed, your family history and genes, and taking the contraceptive pill or HRT, also play a part.
What should I do now?
Women aged 50 to 70 are invited to go for a free mammogram every three years, to look for signs of cancer in their breasts. Most breast cancers happen in women older than 50.
If you are a woman aged 50 or over, you might want to go for a mammogram. You should be invited before your 53rd birthday. If you haven't had an invitation, or you've missed your scan in the past, ask your doctor when you can next go along for screening. If you're over 70 you won't be routinely offered a scan, but you can have one if you wish. You need to ask your doctor.
If you are worried about your risk of breast cancer, because you have relatives with the disease, ask your doctor if you should have a scan at a younger age.
From:
Mammographic breast density by area of residence: evidence of lower density in rural areas. Abstract LL-BR2125-H06, presented at the annual meeting of the Radiological Society of North America, Chicago, US, 26 November 2007.
To find out more, see our information on breast cancer.
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This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
