Systemic treatment in breast cancer Towards a golden ratio

Breast cancer affects over 2 million patients worldwide annually. Systemic treatment options for breast cancer are ample, and vary from endocrine treatment to chemotherapy and targeted therapies. Systemic therapies hold great promise for patients, but also come with a risk of toxicity for patients (in terms of side effects) as well as societies (in terms of resource use). This thesis describes several studies aimed at optimizing different types of systemic treatment for patients with breast cancer. The main findings include:
- The use of aromatase inhibitors in early breast cancer is not associated with early markers for cardiovascular disease (carotid intima media thickness, advanced glycation end products and dyslipidemia)
- Patients with limited metastatic burden, so-called oligometastatic disease, have a favorable prognosis compared to patients with more widespread disease
- Intensified alkylating chemotherapy does not improve clinical outcome compared to standard chemotherapy regimens in patients with oligometastatic breast cancer, whose tumor harbors homologous recombination deficiency
- Using CDK4/6 inhibitors in first- versus second-line does not provide clinical benefit (in terms of progression-free nor overall survival) and is associated with an increase in toxicity for patients and higher drug expenditures for societies
- Efficiency clinical trials are essential for affordable and sustainable health care