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

This review article outlines how the 2025 update of the German S3 rectal cancer guidelines reshapes pathological workup and reporting, with direct consequences for surgical and interdisciplinary decision-making.

Key points:

• • Central role of pathology in treatment planning

  Pathological diagnostics are highlighted as pivotal for stage-adapted and individualized rectal cancer therapy, influencing whether and how surgery, radiotherapy, and systemic therapy are used.

• • Standardized mismatch repair (MMR) testing at diagnosis

  Routine assessment of MMR status is now required at initial diagnosis. This supports detection of Lynch syndrome and informs prognosis and potential systemic treatment options within multimodal concepts.

• • Resection specimen quality and circumferential resection margin (CRM)

  The guidelines further specify standardized evaluation and documentation of specimen quality, with particular emphasis on CRM status. This is framed as critical for local control, risk assessment, and the need for (neo)adjuvant treatment.

• • Refined risk stratification in early-stage disease

  More granular pathological criteria for early rectal carcinomas are described, supporting better selection between local excision and radical surgery, and guiding intensity of follow-up and adjuvant therapy.

• • Growing importance of molecular biomarkers

  Molecular and predictive markers beyond MMR are presented as increasingly relevant elements of multimodal treatment strategies, helping tailor systemic and organ-preserving approaches.

• • Focus on standardized, quality-assured reporting

  The article stresses structured reporting and adherence to guideline-defined minimum datasets to ensure reproducible, high-quality pathology results that can be reliably used in tumor boards and surgical planning.

Overall, the review translates updated guideline requirements into practical implications for pathology and surgery, aiming to strengthen interdisciplinary coordination and improve outcome-oriented, personalized management of rectal cancer.