ACR Appropriateness Criteria® Indolent Lung Cancer.

Persistent or slow-growing subsolid nodules and atypical lung cysts often represent indolent forms of lung cancer. These nodules require careful assessment by a multidisciplinary tumor board to determine risk, natural history, treatment options, and patient preferences. When the preferred management is imaging surveillance rather than active intervention, the main objective is to detect significant changes that could alter patient management. The choice of imaging modality should be based on its accuracy and whether the findings will influence the decision to pursue treatment. If the team determines that treatment is necessary, a diagnostic imaging workup and a biopsy are typically indicated and should not be considered part of surveillance. Therefore, this document aims to outline evidence-based guidelines specifically for imaging surveillance of indolent pulmonary nodules in patients for whom the clinical team has chosen to delay intervention. 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.