Breast cancer and common malignancies in older adults

Cancer is increasingly a diseases of older adults. However, they are heterogeneous and life expectancy and tolerance to stressors may vary greatly within this age group. Comorbidities, functional impairments, malnutrition, polypharmacy, cognitive impairment, psychological distress and lack of social support, may substantially impact on the wellbeing of older adults, on anticancer treatment benefits and toxicities and on clinical decision-making. Treatment decisions should not be guided by chronological age alone. Geriatric assessments can provide a more comprehensive understanding of functional and physiological age in older individuals with cancer to better assess treatment risks and benefits, engage in shared decision-making and provide more personalised care. This thesis describes the impact of age and comorbidities on different aspects of the management of breast cancer and other common malignancies in five research projects. The first project evaluated the patterns of systemic therapy use in older adults with early breast cancer enrolled in the Bridging the Age Gap study and its effect on recurrence and survival outcomes. Since treatment effects on quality of life may be more relevant in the context of more limited life expectancy and reduced survival benefits, the second study investigated the impact of chemotherapy on this specific outcome in adults with early breast cancer at high risk of recurrence enrolled in the same trial. The radiotherapy use patterns and its effect on quality of life were evaluated in a third project including the same trial population. As cardiovascular disease is critical in determining fitness, the fourth study investigated the prevalence of this comorbidity in individuals with curable malignancies retrieved from a national cancer registry dataset linked to cardiovascular disease databases. Finally, the fifth project assessed the cardiac toxicity risk and the performance of a cardiotoxicity prediction tool in older and younger patients with early breast cancer receiving trastuzumab