Evolution of neoadjuvant chemotherapy in locally advanced HER2-positive breast cancer over 10 years in Hong Kong

Abstract

AIM/BACKGROUND: Over the last 10 years we witnessed major changes in treatment for locally advanced HER2-positive breast cancer. The emergence of multiple anti-HER2 therapies and recognition of pathological complete response (pCR) as the surrogate marker for survival are the major landmarks. The clinical benefit of this approach and effects on patient behaviour in Asian countries has not been reported. METHODS: This retrospective study summarizes the changes in practice and outcome during the period 2005 to 2015 from a tertiary referral center in Hong Kong. Patients were divided into 3 groups according to the NAC they received: chemotherapy only (CH), chemotherapy plus trastuzumab (CH-H), and chemotherapy plus double anti- HER2 therapies (CH-DH). RESULTS: There were 177 patients captured during this period and significantly more pre-menopausal women in the groups receiving anti-HER2 therapies (*p < 0.01). Rate of pCR was higher in patients who received anti-HER2 therapies (*p < 0.01), with patients in CH-DH group had more pCR than those in CH-H group (**p < 0.01). This was accompanied by a trend in increase rate of breast conservation therapy (BCT). The estimated recurrent-free-survival (censored) at 5 years was 57% (CH), 76% (CH-H), and 93% (CH-DH) respectively with a mean follow up of 4.2 years. Longer follow up would be required for conclusive results. CONCLUSIONS: Current approach of NAC using CH-H and CH-DH appeared to derive similar favourable pCR rate in Asian patients compared with published results. The option of BCT after the enhanced tumor shrinkage achieved with NAC may explain the preference of NAC in HER-positive premenopausal women. Combination NAC with double anti-HER2 therapy is likely to become the preferred option to achieve higher BCT rates.