Human epidermal growth receptor-2 overexpressing early operable primary breast cancers in older (≥70 years) women: Biology and clinical outcome in comparison with younger (<70 years) patients.

Abstract

e11608 Background: There is dearth of literature reporting the prevalence and biological characteristics as well as the long-term clinical outcome of HER2 positive tumors in older women. This study aimed to analyse their biological characteristics and compare them with their younger counterparts from a single centre with long-term clinical follow-up. Methods: Over 37 years (1973-2010), 1,758 older (≥70 years) women with early operable (<5cm) primary breast cancer were managed in a dedicated clinic and have complete clinical information available. Of these 813 patients underwent primary surgery and 575 had good quality tumour samples available for tissue microarray (TMA) analysis using immunohistochemistry. Comparison was made with data from a well-characterised younger (<70years) series (N=1,711) treated between1986 - 1998 (before adjuvant trastuzumab became standard) in our institution. Thirty-nine (7.6%) and 140 (8.2%) patients from the older and younger series respectively (p=0.56) had HER2-positive tumours. Results: See Table. Conclusions: The HER2 positive tumours in older women showed relatively less aggressive phenotype and did not show any inferior long-term clinical outcome despite not having received chemotherapy as compared to the younger patients. The precise role of different adjuvant systemic therapies in this population needs to be delineated. [Table: see text]