Headline-grabbing drugs may not be suitable for many black patients
Black women seem to develop breast cancer significantly earlier than their white contemporaries, the first UK study into differences suggests.
A survey of 293 women in the ethnically mixed London borough of Hackney found black women were 21 years younger than white women when they were diagnosed.
There may be biological differences in how the disease develops, the British Journal of Cancer study suggests.
Researchers say further work is needed into a field which has been neglected.
While it is known that breast cancer affects more white women than black, UK cancer registries have only recently started to collect ethnicity data and there is little understanding of if, and indeed how, race affects the development of the disease.
Drugs don't work
The 102 black patients were diagnosed with breast cancer at an average age of 46 while the 191 white patients were on average 67.
The team sought to make sure that other external factors did not unduly influence the results by comparing women of broadly similar socio-economic backgrounds.
While there were no major differences in survival rates over the eleven year period studied, the younger black women were more likely to have smaller, more aggressive cancers.
These are less likely to respond to the new, well-publicised cancer drugs such as Herceptin, Dr Rebecca Bowen, who led the study said.
"We are thinking along the lines that these results are down to biological differences. More research is needed to see if this stands up, and then to work out what the implications are."
Dr Lesley Walker of Cancer Research UK, which helped fund the study, said the findings were "clearly worrying".
"If these results are confirmed in follow-up studies, it might be appropriate to alter screening services offered to black women to better reflect the age at which they are diagnosed with breast cancer but at the moment it's too early to suggest any changes to the screening programme because the study was so small."
Breast Cancer Care also described the study as worrying.
"The potential for younger age of onset and more aggressive breast cancers in this group of women makes breast awareness even more important to help ensure they are diagnosed as soon as possible," said Dr Emma Pennery.