Ethnic differences in breast cancer risk factor to be examined

Cancer Research UK launches a new study today to investigate factors that influence breast density, a strong risk factor for breast cancer, in different ethnic groups.

Researchers will examine breast density, a known risk factor for breast cancer, in British White, African Caribbean and South Asian women in the UK.

Breast density is a measure of the proportion of dense tissue as opposed to fatty tissue in the breast. Women with dense breast tissue have a higher risk of subsequent breast cancer.

Measured using mammography, dense tissue appears as white areas on a mammogram, whereas black areas represent non-dense fatty tissue.

The team hope the study will reveal modifiable risk factors for breast density that could potentially identify ways to help reduce a woman’s chance of developing breast cancer.

In general, South Asian women living in England are less likely to be diagnosed with breast cancer than their English-native counterparts.

Despite differences in breast cancer incidence rates between ethnic groups in the UK, studies of ethnic variations in breast density have not been conducted until now.

Valerie McCormack, funded by Cancer Research UK and based at the London School of Hygiene and Tropical Medicine, says: “Previous studies in the UK have looked at breast density in White populations but this is the first to look at different ethnic groups.

“We plan to look at how lifestyle factors and hormones affect breast density and its changes over time in women of White, South Asian and African Caribbean ethnicity.

Over the next two years, the researchers will recruit 1,000 White, African Caribbean and South Asian post-menopausal women who attended the NHS Central and East London Breast Screening Service for routine breast cancer screening.

Participants will be asked to fill out a detailed questionnaire which will include questions on breast-feeding practices, use of oral contraceptives, family history of breast cancer, diet, alcohol intake and weight.

The team will use women’s mammograms to work out their breast density and take a blood sample to test for levels of female hormones.

They will look at breast density at specific ages and also at how a woman’s density changes over time as she passes through the NHS breast screening programme. They will examine ethnic variations in these measures and investigate the extent to which differences in lifestyle and hormonal risk factors can explain the variations.

Valerie McCormack says: “We hope to find which breast cancer risk factors act through the breast density pathway.”

Dr Lesley Walker, Director of Cancer Information at Cancer Research UK, says: “High breast density is a strong risk factor for breast cancer. This study will help us understand more about the biological basis of dense breast tissue in an ethnically diverse population. It may also identify modifiable risk factors for dense breast tissue that could be used in future breast cancer prevention strategies.”

ENDS