Anatomic pathology reports (APR) provide diagnostic and prognostic information crucial to patient care, clinical research and epidemiology. Currently, it is difficult to collect and exchange APR data between different healthcare organizations at an international level. Objective: IHE and HL7 anatomic pathology joint efforts aim at providing a methodology and tools to define an international HL7 "Clinical Document Architecture" (CDA) implementation guide for APRs and especially in the domain of cancer. Methods: A four-step methodology is employed, consisting of comparing existing clinical model of APRs originating from different countries; deriving consensus-based clinical models (Delphi technique); providing the corresponding HL7 CDA implementation guide ("CDA templates") and validating these templates. Results: International experts defined HL7 CDA implementation guides for breast and colon cancer APRs within an IHE content profile. CDA templates include required data elements, as well as optional ones, that can be further specified as required in national extensions. Conclusion: This study demonstrates that it is possible to define an international HL7 CDA implementation guide for cancer APRs. Further efforts are needed to provide CDA templates for approximately 60 other cancer APRs dedicated to different organs, diagnoses, and procedures as well as for APRs of non neoplastic pathologies. The methodology is not confined to APRs and could be applied to clinical documents of any type.