Catching and monitoring clinical innovation through performance indicators. The case of the breast-conserving surgery indicator.

Background: The evolution in the surgical and diagnostic procedures, the attention to women's preferences, the case mix, and differences in professional practices may lead to a variability in the quality of breast cancer clinical pathway. To catch and manage this variability it is important to use valid measures. The aim of this paper is to examine the concurrent validity of the breast-conserving surgery (BCS) indicator and to provide evidence to guide the quality improvement process.