Utility of Maximum Standard Uptake Value as a Predictor for Differentiating the Invasiveness of T1 Stage Pulmonary Adenocarcinoma

Background

The present study was performed to investigate the maximum standardized uptake value (SUVmax) in 2-fluorine-18]-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to preoperatively distinguish invasive from less-invasive pulmonary adenocarcinoma.

Patients and Methods

A total of 106 patients with resectable pulmonary adenocarcinoma (≤ 3 cm) who had undergone whole-body ¹⁸F-FDG PET/CT were enrolled. The SUVmax, diameter, and consolidation/tumor (C/T) ratio of the lung tumors were measured with ¹⁸F-FDG PET/CT and regional thin-section CT.

Results

Of the 106 patients, 32 had adenocarcinoma in situ (AIS), 13 had minimally invasive adenocarcinoma (MIA), and 61 had invasive adenocarcinoma (IAC). IAC lesions showed greater uptake of ¹⁸F-FDG, a larger tumor diameter, and greater C/T ratios than AIS and MIA (P < .001 for all). A multivariate analysis revealed that only the SUVmax, tumor diameter, and C/T ratio were independent risk factors for tumor invasiveness (P < .05 for all). The best cutoff values for the prediction of invasiveness were 2.15 for the SUVmax, 1.36 cm for the tumor diameter, and 0.36 for the C/T ratio. The SUVmax, tumor diameter, and C/T ratio showed similar predictive sensitivity (83.6%, 82.0%, and 88.5%, respectively). However, the SUVmax showed a greater predictive specificity than the C/T ratio (93.3% vs. 73.3%, respectively; P = .011) but similar to that of the tumor diameter. The predictive sensitivity and specificity were not improved using the 3 combined parameters compared with SUVmax alone.

Conclusion

The present study has demonstrated that the SUVmax is a good preoperative predictor for the invasiveness of pulmonary adenocarcinoma (≤ 3 cm). It will help surgeons plan low invasive treatment of preinvasive tumors.