Breast cancer reports form an important part of the basis of clinical decision making for patients. Our objectives were to improve breast cancer reporting in the Urban Central Region in Utah of Intermountain Health Care in a clinically relevant manner and to show that the method chosen actually improved information transfer among physicians of breast cancer patients and led to durable changes in pathologist behavior. METHODS/INTERVENTION: Pathologists designed a synoptic report based on interviews with oncologists about what data were meaningful. The report format was piloted with one hospital pathology group, modified, and implemented in three hospitals. A report evaluation of missing information was done before, immediately after, and 2 years after the intervention. Oncologists were surveyed after 2 years to evaluate satisfaction with report format. Changing breast cancer reporting to a synoptic format significantly decreased information missing from pathology reports. Prior to implementation, 32 of 365 reports lacked some item(s) of pathology information desirable to clinicians; after the intervention, 8 of 250 reports contained missing information. After 2 years, 1 in 190 reports contained missing data elements. Synoptic breast cancer reports continued to be used by pathologists throughout the reporting period. Oncologists responding to a survey reported uniform satisfaction with the new reporting format. Pathologists are important members of the clinical oncology team. They provide patient-specific information crucial to patient care. Activities designed to improve the quality of reporting processes should use clinically relevant indicators of process improvement, such as measurement of missing information and satisfaction of clinical colleagues with format/quality of information.