Objective: Several studies have suggested that positron emission tomography is more accurate than computed tomography for the staging of non-small cell lung cancer and can reduce the rate of unnecessary thoracotomy in patients with potentially resectable disease. However, there are few data on the utility of positron emission tomography in the diagnosis of patients with tumors of 2 cm or less in size.
Methods: Patients with cT1/cT2 tumors of 2 cm or less in size were retrospectively reviewed. All had a computed tomographic scan, as well as a positron emission tomographic scan on a dedicated scanner, with a standard uptake value reported. A standard uptake value of 2.5 g/mL or greater was considered positive. The results of computed tomography and positron emission tomography were correlated with pathologic results after either resection (n = 60) or mediastinoscopy (n = 4).
Results: Sixty-four patients (38 women; mean age, 66 years) had a mean tumor size of 1.4 cm (range, 0.7-2.0 cm). Forty-three patients had adenocarcinoma, 13 had adenocarcinoma-bronchioloalveolar carcinoma, 5 had squamous cell carcinoma, and 3 had other tumor types. Twenty-nine (45%) tumors had negative positron emission tomographic results. Both tumor size (>1 cm vs < or =1 cm) and cell type (adenocarcinoma-bronchioloalveolar carcinoma vs all other cell types) were significant predictors of positron emission tomography uptake in the primary tumor (P = .05 and .01, respectively). Nodal metastases were detected pathologically in 11 (17%) patients (5 N1 and 6 N2). Positron emission tomographic sensitivity and specificity for nodal metastases were only 45% and 89%, respectively. There was no statistically demonstrable survival difference between positron emission tomography-positive and positron emission tomography-negative tumors (3-year survival of 87% vs 100%, respectively).
Conclusion: Positron emission tomographic scanning has no demonstrable benefit in the diagnosis, staging, or prognosis of patients with tumors of 2 cm or less in size.