ABSTRACTS XVI ALASBIMN CONGRESS  NUCLEAR MEDICINE 1999.

9. LUNG

R.P.Baum¹, K. Plichta¹, M.Schmücking², N.Presselt¹, R.Bonnet¹, A. Niesen¹, E. Lopatta², J. Leonhardi¹

Zentralklinik Bad Berka¹ (PET Center, Dept. of Diagnostic Radiology, Dept. of Thoracic Surgery and Dept. of Pneumology) Bad Berka, Germany

University of Jena Medical School², Dept. of Radiotherapy, Jena, Germany

baum@em.uni-frankfurt.de

Objective: To determine the role of F-18 FDG-PET for staging non-small cell lung cancer (NSCLC), findings in 33 patients treated surgically were analyzed in a prospective way.

Methods: PET data (whole-body ECAT Exact 47, Siemens/CTI) were correlated by McNemar and Bowker test with CT data (Somatom Plus 4) and histological findings.

Results: Based on histopathological findings (gold standard), nodal involvement and M-status differed in 52% and 27% of the patients, respectively, when comparing F-18 FDG-PET with CT. Consequently, therapeutic management was changed in 52% (from curative to palliative treatment in 19% of the patients) based on the PET results. PET correctly identified lymph node metastases with a sensitivity of 73% (8/11) and a specificity of 82% (18/22). None of the histologically proven pNI lesions were detected by PET due to micrometastases in one case and due to massive FDG uptake in the primary tumor located closely to the mediastinum (SUV > 13, metabolic diameter > 4.5cm). However, all pN2 and pN3 lesions were staged correctly (100% sensitivity for pN2 / pN3 lymph node metastases).

Overall diagnostic accuracy was 79%. The positive and negative predictive values of PET imaging for lymph node staging were 76% and 86%, respectively. There were four false-positive cases with a moderate increase in' FDG uptake due to anthracosilicotic nodules, nonspecific tumor-related inflammation or due to radiation pneumonitis / lymphadenitis.

Conclusions: Our data (ongoing study) demonstrate that F-18 FDG-PET metabolic imaging as a noninvasive technique provides an important complementary tool to the morphological imaging modalities. With a sensitivity of 100% mediastinal lymph nodes were staged exactly by FDG-PET.

Key Words. PET, FDG, non-small cell lung cancer.

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