Triple-negative breast cancer in Hong Kong Chinese patients

Abstract

Background: There is increasing data showing that breast cancer is a heterogeneous disease which should be assessed separately in different populations, as it differs substantially between Chinese and Caucasian women. Triple-negative breast tumours which are negative for ER, PR and HER-2 neu receptors are associated with younger age at presentation, tumour of higher grade with larger size and a poorer prognosis. There is recent suggestion that the prognostic outlook of Chinese triple-negative breast cancers might be somewhat different from those in the Western population, but few studies have attempted to understand the role of ethnic factor in the triple-negative entity. Methods: We conducted a preliminary retrospective comparison of 170 Hong Kong Chinese primary breast cancer patients seen as new cases during January 2004 and December 2004 in a teaching hospital. Clinico-pathological features of triple-negative tumours were compared to their non-triple-negative counterpart. Results: Triple negative breast cancer accounted for 12.4% of all breast cancer patients seen in the year of 2004 (n = 21). It is associated with more cancers with grade 3 tumour (68.4% vs 36.8%; p = 0.02) but there was no statistically difference between the age of presentation, tumour size, extensive intraductal component, lymph node status and rate of local relapse or metastasis after adjuvant therapy. Subset analysis further revealed that when triple negative breast cancer patients (n = 21) were compared to the HER-2 positive patients (n = 40) in the studied population, HER-2 positive patients were still associated with higher proportion of node positive disease (57.5% vs 30.0%; p = 0.04). Disease free survival and overall survival were not studied due to limited follow-up time. Conclusions: Our preliminary findings suggested that Hong Kong Chinese triple-negative breast cancers are associated with a more favourable outlook and might behave differently when compared to their Western counterpart. Further large-scale study of the ethnic factor with long-term follow-up is warranted.