Background: Structuring cancer care into pathways can reduce variability in clinical practice and improve patient outcomes. International benchmarking can help centers with regard to development, implementation, and evaluation. A further step in the development of multidisciplinary care is to organize care in integrated practice units (IPUs), encompassing the whole pathway and relevant organizational aspects. However, research on this topic is limited. This article describes the development and results of a benchmark tool for cancer care pathways and explores IPU development in cancer centers. Methods: The benchmark tool was developed according to a 13-step benchmarking method and piloted in 7 European cancer centers. Centers provided data and site visits were performed to understand the context in which the cancer center operates and to clarify additional questions. Benchmark data were structured into pathway development and evaluation and assessed against key IPU features. Results: Benchmark results showed that most centers have formalized multidisciplinary pathways and that care teams differed in composition, and found almost 2-fold differences in mammography use efficiency. Suggestions for improvement included positioning pathways formally and structurally evaluating outcomes at a sufficiently high frequency. Based on the benchmark, 3 centers indicating that they had a breast cancer IPU were scored differently on implementation. Overall, we found that centers in Europe are in various stages of development of pathways and IPUs, ranging from an informal pathway structure to a full IPU-type of organization. Conclusions: A benchmark tool for care pathways was successfully developed and tested, and is available in an open format. Our tool allows for the assessment of pathway organization and can be used to assess the status of IPU development. Opportunities for improvement were identified regarding the organization of care pathways and the development toward IPUs. Three centers are in varying degrees of implementation and can be characterized as breast cancer IPUs. Organizing cancer care in an IPU could yield multiple performance improvements.