The impact of tumour biology on the management of primary breast cancer in older women—based on a research programme in Nottingham

Abstract

: The incidence of breast cancer increases with age. Average life expectancies are increasing; the older population is expanding globally. This presents a huge challenge on an international scale in the coming years as more older people are living with breast cancer. Despite this, most research in this field remains focused in younger patients. In this article, we outline the current issues facing understanding of the biology of primary breast cancer in older women with regards to treatment decision making. The main treatment dilemmas concern (I) primary treatment [surgery versus non-operative therapies in estrogen receptor (ER) positive and negative tumours] and (II) adjuvant treatment (such as endocrine therapy or chemotherapy). We then discuss work in this field from the Nottingham Breast Cancer Research Centre, which includes biological assessment of a large (N=1,758) cohort of older (aged ≥70 years) women with primary breast cancer with long-term follow-up data. At a biological level, we understand breast cancer belongs to four main subtypes [luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) over-expression, or triple negative breast cancer (TNBC)], with treatment plans based upon these. The Nottingham group have found a biological cluster unique to older women with primary breast cancer (low ER luminal type), which is not seen in their younger (<70 years) counterparts, as well as differences between age and clinical outcome in patients with ER-positive, HER2-positive and TNBC. This adds further evidence that the biology of breast cancer in older women is different to that of younger women and therefore, should be treated as such.