OA02.09 Multi-Planar Lung Cancer Measurements Provide Improved Accuracy in Clinical Staging

Abstract

Despite the wealth of information available via routine diagnostic computed tomography (CT), tumors are conventionally measured and reported in the axial dimension only. The extent to which this practice may underestimate tumor burden and impair accurate clinical staging is unknown. We sought to evaluate the impact of adding sagittal and coronal measurements to patient imaging review, as well as its role in determining candidates for potential neoadjuvant treatment in advance of surgical resection. Consecutive patients were identified who underwent upfront surgery from 2010-2015 for clinical T2N0-1 non-small cell lung cancer (AJCC 7th Edition) at a single institution. Patients without available pre-operative CT, with pre-operative CT of poor quality (slice thickness >5mm), and patients who had multifocal disease or associated atelectasis precluding accurate tumor measurement were excluded. Imaging was reviewed by thoracic radiologists and longest tumor diameter in axial, sagittal, and coronal planes were reported. 152 patients were identified for detailed imaging review, including 106 (70%) who were initially reported as T2a and 46 (30%) T2b based upon axial images. Review of reformats revealed T stages ranging from T1b-T3 in the coronal plane, and T1a-T3 in the sagittal plane (Table). Axial-coronal and axial-sagittal T stage concordance were 76% (115/152) and 75% (114/152), respectively. Coronal-sagittal concordance was 70% (106/152). Importantly, 5% (8/152) were upstaged to T3 based upon three-dimensional measurements, suggesting a potential missed opportunity for induction chemotherapy. Spearman’s correlation coefficient demonstrated the highest agreement between pathologic tumor size and axial diameter (ρ=0.70), as compared to coronal (ρ=0.68) and sagittal (ρ=0.64) measurements. A modest but important proportion of patients are eligible for chemotherapy when three-dimensional tumor measurements are employed. Because prior investigations have demonstrated improved compliance with regards to completion of chemotherapy in the neoadjuvant (versus adjuvant) setting, routine measurement of tumors in three dimensions should be considered.