Purpose In the Netherlands, radiotherapy after breast-conserving surgery (BCS) is omitted in up to 30% of patients aged >= 75 years. Although omission of radiotherapy is considered an option for... Show morePurpose In the Netherlands, radiotherapy after breast-conserving surgery (BCS) is omitted in up to 30% of patients aged >= 75 years. Although omission of radiotherapy is considered an option for older women treated with endocrine treatment, the majority of these patients do not receive systemic treatment following Dutch treatment guidelines. Therefore, the aim of this study was to evaluate the effect of omission of radiotherapy on locoregional recurrence risk in this patient population.Methods Patients aged >= 75 years undergone BCS for T1-2N0 breast cancer diagnosed between 2003 and 2009 were selected from the Netherlands Cancer Registry. To minimize confounding by indication, hospital variation was used to assess the impact of radiotherapy-use on locoregional recurrence risk using cox proportional hazards regression. Hazards ratios with 95% confidence interval (CI) were estimated.Results Overall, 2390 patients were included. Of the patients with hormone receptor-positive breast cancer, 39.3% received endocrine treatment. Five-year incidences of locoregional recurrence were 1.9%, 2.8%, and 3.0% in patients treated at hospitals with higher (average radiotherapy-use 96.0%), moderate (88.0%), and lower radiotherapy-use (72.2%) respectively, and nine-year incidences were 2.2%, 3.1%, and 3.2% respectively. Adjusted hazard ratios were 1.46 (95% CI 0.77-2.78) and 1.50 (95% CI 0.79-2.85) for patients treated at hospitals with moderate and lower radiotherapy-use, compared to patient treated at hospitals with higher radiotherapy-use.Conclusions Despite endocrine treatment in only 39.3%, locoregional recurrence risk was low, even in patients treated at hospitals with lower radiotherapy-use. This provides reasonable grounds to consider omission of radiotherapy in patients aged >= 75 years with T1-2N0 breast cancer. Show less
Ettema, R.; Heim, N.; Hamaker, M.; Emmelot-Vonk, M.; Mast, R. van der; Schuurmans, M. 2018
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
