Tying a surgical knot in breast cancer outcomes

The main aim of this thesis was to add knowledge on how to improve outcomes of breast cancer surgery. Cosmetic outcome and quality of life play an important role in the treatment decision between breast conserving surgery (BCS) and mastectomy. First of all, a new tool to predict cosmetic outcome after BCS was investigated and found to be of value. Based on this tool, a treatment decision model was presented between BCS and mastectomy. This decision model is clinically relevant since it is the first objective aid for patients and surgeons in the complex and subjective decision they face. Secondly, different options were explored to reduce reexcision rates. This is relevant since it potentially improves cosmetic outcome, improves quality of life, reduces secondary mastectomies, reduces health care costs and reduces surgical complications. Use of preoperative MRI was found not to reduce reexcision rate. The safety of omitting a reexcision in case of focally positive margins after BCS was studied. Local recurrence rate, disease-free survival and overall survival was comparable and it appeared safe. Finally, quality indicators for breast cancer care monitored in the Netherlands were studied. Between hospital differences are increasingly being reported. However this information can be misinterpreted if quality indicators are not valid or reliable. It was concluded that comparisons and judgments of individual hospital performance should be made with caution. Consequently, a new summarizing measure was presented to rank hospitals and discriminate outliers. This potentially increases the impact and use of quality of care information.