Singapore - Family history plays key role in predicting breast cancer risk: study

SINGAPORE: A study by the National Cancer Centre Singapore (NCCS) has shown that family history of breast cancer is a strong indicator of breast cancer risk among local women.

A history of at least one affected immediate relative (for example, a mother, daughter or sister) is twice as important for breast cancer risk in Singapore women relative to Western women.

The study also showed that the Gail Model - a standard model used in Western populations to predict individual risk of breast cancer - was inaccurate in the local population.

Dr Chay Wen Yee, one of the researchers said: "Our study showed that the Gail Model over-estimated the risk of breast cancer among local women. This shows that methods used to predict risk of breast cancer in the West do not provide accurate estimates in our setting."

Dr Tan Min-Han, a medical oncologist and cancer geneticist, said: "These study findings mean that local doctors must place a greater emphasis on family history to accurately predict a woman's risk for breast cancer, and indeed, for any cancer.

"A carefully taken family history is a cheap, proven and easily available method to determine proper timing and intensity of cancer screening, and remains the gold standard for establishing risk in patients."

The study involved patients between 50 and 64 years of age who were screened in the Singapore Breast Cancer Screening Project (SBCSP), a large scale prospective community mammography screening program that took place in 1994.

Some 28,000 women were initially screened with mammograms. Over time, the number of observed breast cancer cases were derived and compared to what would have been expected in terms of the Gail Model.

The study focused on evaluating whether the Gail Model was useful in predicting risk in the Singapore population.

The study, which was recently published in the top breast cancer journal "Breast Cancer Research", evaluated for the first time the association between breast cancer incidence and established risk factors in a large prospective study in Asia.

The results will have bearing on advising local women on personal breast cancer risk, as well as decisions on when to initiate medications for breast cancer prevention.

Breast cancer is the most common type of cancer among Singapore women. From 1968 to 2007, Singapore showed an almost threefold increase in breast cancer incidence.

Between 2006 and 2010, 7,781 cases were detected and accounted for 29.3 per cent of all cancers affecting Singaporean women.

- CNA/cc