Standardized Uptake Values in the Primary Lesions of Non-Small-Cell Lung Cancer in FDG-PET/CT Can Predict Regional Lymph Node Metastases

Purpose. Maximum standardized uptake values (SUVmax) at the primary lesions of non-small-cell lung cancer in F-18-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT), and the microscopic local extension of tumors were examined to develop reliable criteria to determine candidates for sublobar resection. Methods. We retrospectively analyzed 209 patients who underwent lobectomy, bilobectomy, or pneumonectomy with systematic lymph node dissection. Preoperative SUVmax at the primary lesion, microscopic lymphatic, venous, and pleural invasion in addition to lymph node metastases in the resected specimens were examined. Receiver operating characteristic analyses were used to predict an optimal cutoff for lymph node metastases. Results. With receiver operating characteristic analysis, the areas under the curve for SUVmax and tumor size were 0.693 and 0.545, respectively, suggesting SUVmax superiority for prediction of lymph node metastases with a cutoff of 2.9. When a tumor was <= 2.0 cm (n = 41, 19.6 %), the percentages of microscopic lymphatic invasion, venous invasion, pleural invasion, and lymph node metastases were 12.2, 7.3, 4.9, and 17.1 %, respectively. When SUVmax was <3.0 (n = 91, 43.5 %), these percentages were 15.4, 3.3, 7.7, and 8.8 %, showing that SUVmax could efficiently exclude nodal metastases in more cases than tumor size. The postoperative 5-year survival rate was 86.6 % in patients with SUVmax < 3.0 and 58.1 % in patients with SUVmax >= 3.0 (p < 0.001). Conclusions. F-18-FDG uptake value was more useful than tumor size for selecting patients with non-small-cell lung cancer suitable for intentional sublobar resection.