Human epidermal growth receptor-2 overexpressing early operable primary breast cancers in older (>=70 years) women: biology and clinical outcome in comparison with younger (less than 70 years) patients

Introduction: There is dearth of literature reporting the prevalence and biological characteristics as well as the long-termclinical outcome of human epidermal growth factor receptor-2 (HER2) overexpressing tumours in older women. Currently,research involving trastuzumab at large focuses on the younger population. This study aimed to analyse their biological characteristicsand to compare them with their younger counterparts from a single centre with a long-term clinical follow-up.Methods: Over 37 years (1973–2010), 1758 older (≥70 years) women with early operable (less than 5 cm) 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 analysis using indirect immunohistochemistry. Comparison was made with data from a well-characterised younger (70 years = 70%, P = 0.51).Conclusion:HER2 overexpressing tumours in older women showed relatively a less aggressive phenotype and did not show any inferior long-term clinical outcome despite not having received chemotherapy when compared with the younger patients. The precise role of different adjuvant systemic therapies in this population needs to be delineated