Clinical Stage IA Lung Cancer by CT and PET Scan: The Persistent Problem of Understaging
Brendon M. Stiles, Paul C. Lee, Elliot L. Servais, Jeffrey L. Port, Subroto Paul, Danish Meherally, Nasser K. Altorki; Weill Cornell Medical College, New York Presbyterian Hospital, New York, NY
Comment on this Abstract
Objective: There appears to be an increased interest in limited resection for clinical stage IA NSCLC. This treatment strategy depends upon the accuracy of clinical staging, which has not been validated for stage IA NSCLC using all currently available imaging technology. The purpose of this study was to determine the accuracy of clinical staging for stage IA NSCLC patients who underwent both CT and PET scans and to determine factors associated with understaging.
Methods: A retrospective review of a prospectively maintained database of patients with NSCLC was performed. Clinical stage IA patients by preoperative CT and PET scan were reviewed. The influence of the following factors was analyzed with regard to accuracy of clinical staging: tumor size, location, histology and PET positivity.
Results: Of the 266 patients identified, only 65% were correctly staged. Final pathologic stages also included IB (15%), IIA (2.6%), IIB (4.1%), IIIA (4.9%), IIIB (7.5%), and IV (.08%). Positive lymph nodes were found in 11.7% of patients. Pathologic T-stage changed in 28.2% of patients. Patients with clinical tumor size >2cm (n=35) were significantly more likely to be understaged than patients with tumors ≤2cm (49% vs. 29%, p=.003). Overall, patients with a PET +ve primary (n=218) were also more likely to be understaged than those with PET -ve primaries; (39% vs. 15%, p=.001). Fifty-five percent of patients with PET +ve tumors >2cm were clinically understaged, compared to 32% for PET +ve tumors ≤2 cm, and only 17% for PET-ve tumors <2cm. Lobar location and histology were not predictors of accuracy of clinical staging.
Conclusion: Patients with clinical stage IA lung cancer are frequently understaged, despite the performance of preoperative CT and PET scans. Size >2cm and PET positivity are risk factors for understaging. Limited resection should be undertaken with caution in such patients.
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