Whether cigarette smoking raises a woman’s chances of ever developing breast cancer has remained a controversial question, with some research indicating a risk and other studies not.
Researchers at Fox Chase Cancer Centre in Philadelphia investigated whether female smokers who got breast cancer were more likely to have a more serious form.
They analysed data on 6,162 women with breast cancer evaluated at the facility from 1970 to 2006, and found that whether a woman smoked did not affect whether her tumour was more advanced or particularly aggressive at the time of diagnosis.
Nine per cent of the breast cancer patients were smokers when they were first seen.
"For patients who developed breast cancer, there did not appear to be a difference in the cancers that they presented with based on whether or not they had ever smoked," Dr Matthew Abramowitz of Fox Chase Cancer Centre, one of the researchers, said.