Evaluation of the prognostic value of 2005 St Gallen risk categories for operated breast cancers in Hong Kong

Incorporating various new and conventional risk factors, the 2005 St Gallen risk categorization is a potentially useful prognostic tool for breast cancers. We conducted a retrospective study to evaluate its application in Hong Kong. Of the 902 included female breast cancers with median follow-up of 5.4 years, 7%, 63% and 30% patients were classified as low-, intermediate- and high-risk categories, respectively. Their corresponding 5-year distant disease-free survivals (DDFS) were 100%, 92% and 72%, respectively (p<0.00005). In the intermediate-risk category, node-positive patients had marginally inferior 5-year DDFS than node-negative patients (89% vs. 93%, p=0.0551). In the high-risk category, patients having HER2 overexpressed tumors and 1-3 positive nodes had significantly better DDFS than other patients with ⩾4 positive nodes (89% vs. 65%, p=0.0001). Overall, the 2005 St Gallen risk categorization had high prognostic value. However, the impact of HER2 overexpression might be affected by reproducibility of HER2 tests.