[Value of Pet-18FDG in lung cancer]

18FDG-PET was studied in the diagnosis of malignancy of the solitary pulmonary nodule and in the early staging of non-small-cell lung cancer. PET results were compared with thoracic-abdominal computed tomography (CT) and brain magnetic resonance (MR).

Fifty-five patients with a radiologically detected solitary pulmonary nodule (54 CT, 1 plain radiography), were studied following an intravenous injection of 370 MBq 18FDG. Attenuation corrected emission data were acquired and analyzed qualitatively and semi-quantitatively. 30 non-small-cell lung cancer underwent MR. Biopsies were obtained in 48 non-small-cell lung cancer and 7 were controlled by follow-up (18 months). The staging of 43 non-small-cell lung cancer was confirmed by surgery (n = 13), mediastinoscopy (n = 9) and follow-up (n = 21).

PET correctly diagnosed 52 solitary pulmonary nodules with 3 false positives (100% sensitivity and 75% specificity). In the mediastinal staging (N), CT and PET demonstrated a sensitivity and specificity of 46% vs. 100%, and 59.3% vs. 93.3%, respectively. In 6 patients, some visceral metastases detected by PET were not detected by CT (including 3 adrenals), whereas 2 brain metastases in MR were not diagnosed by PET. PET was considered decisive in the treatment and follow-up of 17 patients (32.7%).

Whole body PET imaging is a cost-effective diagnostic technique that simplifies the malignant characterization of solitary pulmonary nodule and improves the early staging of non-small-cell lung cancer. In combination with CT, PET makes an outstanding contribution to the correct assessment of therapeutical decisions in these patients.