FDG uptake at the bronchial stump after curative lobectomy for non-small cell lung cancer

Focal areas of FDG uptake may occur at the bronchial stump following curative lobectomy for non-small-cell lung carcinoma (NSCLC), even in the absence of suspicious CT changes. The purpose of our study was to investigate the significance of such PET/CT findings. FDG-PET/CT scans performed in 54 patients after lobectomy for NSCLC were reviewed. The presence of focal areas of FDG uptake at the bronchial stump, associated CT abnormalities, SUVmax, and normalized SUV (SUVnorm = SUVmax/mean liver SUV) were recorded. Final diagnosis was based on biopsy or imaging follow-up. Focal areas of FDG uptake at the bronchial stump were detected in 30 patients (56 %). Mean SUVmax was 4.0 ± 1.9 (range; 2.2-12.1) and mean SUVnorm was 1.8 ± 0.8 (range; 0.9-4.5). Biopsy showed recurrence in two patients. In these patients, SUVnorm was respectively 4.4 and 4.5 (with SUVmax of 8.8 and 12.1), whereas SUVnorm was lower than 4.0 in those without recurrence, with mean SUVnorm of 1.6 ± 0.5 (range; 0.9-3.4) and mean SUVmax of 3.6 ± 0.9 (range; 2.2-5.8). The CT component of the PET/CT revealed ill-defined peribronchial soft tissue opacity only in both patients with recurrence. FDG uptake at the bronchial stump is a frequent finding after pulmonary lobectomy. Moderate levels of FDG uptake (i.e., SUVnorm < 4.0) without corresponding abnormal CT findings might be a dual criterion for diagnosing benign post-surgical changes. (orig.)