[Pathological diagnostics of rectal cancer : New aspects and recommendations of the updated S3 guidelines]

The pathological diagnostics of rectal cancer play a central role in stage-adapted and individualized treatment planning. With the update of the German S3 guidelines in 2025, the requirements for histopathological and molecular reporting have been further specified and expanded. In particular, the standardized assessment of mismatch repair status at initial diagnosis, standardized evaluation of resection specimen quality including the circumferential resection margin as well as refined risk stratification of early stage carcinomas, have direct implications for making surgical decisions. In parallel, molecular biomarkers and predictive factors are gaining increasing relevance within multimodal treatment concepts. This review article summarizes the current guideline recommendations from a pathological perspective and classifies their clinical relevance for the surgical practice. The aim is to deepen the understanding of the diagnostic principles and to emphasize the importance of standardized and quality-assured reporting in the interdisciplinary treatment concept of rectal cancer.