ACR Appropriateness Criteria® Staging and Disease Monitoring of Rectal Cancer.

In rectal cancer, because of the need for high-resolution anatomic detail in determining local tumor extension, imaging for local staging and restaging of the primary tumor in the pelvis is considered separately from the evaluation of distant metastatic disease in the chest, abdomen, and pelvis, often resulting in the need for a combination of modalities to fully stage the patient. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.