Older women with breast cancer are underrepresented in the available evidence. Therefore, there is no solid evidence on how to treat older women with breast cancer. This thesis has three main... Show moreOlder women with breast cancer are underrepresented in the available evidence. Therefore, there is no solid evidence on how to treat older women with breast cancer. This thesis has three main conclusions: 1. There are large international differences in the treatment strategy of breast cancer among older women. These differences are not associated with a significant difference in prognosis. 2. The presence of comorbidity has an important impact on the general prognosis of older women with breast cancer. We did not show an important association between specific comorbidities or the use of co-medications and the breast cancer specific prognosis. 3. Concerning older women with breast cancer for research, there are very important methodological issues to take into account, including to avoidance of selection bias and the proper methodologies to take in to account the chance of dying from another cause of cancer: the competing risk of mortality. Future research should be done to create a tool which can assist in identifying the individualised treatment strategy for each older woman with breast cancer. This will have to take into consideration patient’s and tumour’s information, as well as the endpoints for each individual patient. Show less
Currently, 35-45% of newly diagnosed breast cancer patients in developed countries is aged 65 years and older. Older women with breast cancer comprise a heterogeneous group due to large differences... Show moreCurrently, 35-45% of newly diagnosed breast cancer patients in developed countries is aged 65 years and older. Older women with breast cancer comprise a heterogeneous group due to large differences with regard to concomitant diseases, physiological reserve and functional status. Current guidelines for breast cancer are based on studies that were mostly performed in younger patients. Therefore, treatment of older women with breast cancer is not evidence-based, and it cannot be expected that clinical trials will fill this gap of knowledge in the near future. The aim of this thesis was to investigate several aspects of breast cancer treatment in older women. In Part I, several aspects of treatment in older breast cancer patients were assessed. Part II assessed methodological aspects of studying breast cancer in older patients. This thesis has shown that older patients are at increased risk for overdiagnosis of breast cancer due to population screening, with potential harmful effects due to the increased risk of complications of treatment. Despite changing treatment strategies, breast cancer prognosis of older women has not improved. Current treatment strategies and decisions tools are insufficient. Observational studies will become increasingly important in this patient population, the use of accurate methods will be essential. Show less
