PET/CT Staging of T1-Stage Non-Small Cell Lung Cancer

  • Dr Khalid Salman, University Hospital of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland, Switzerland
  • Dr Christoph Steinmann, University Hospital of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland, Switzerland
  • Dr Vaiyapuri Sukumar, Northampton general hospital, Northampton NN3 3AH, U K., United Kingdom
  • Prof Gustav von Schulthess, University Hospital of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland, Switzerland
  • Prof Hans Steinert, University Hospital of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland, Swaziland

    • Purpose: To evaluate the value of PET/CT in detecting occult metastases in patients with T1-stage non-small-cell lung cancer (NSCLC).

    Method: Patients with proven NSCLC and T1-stage (< 3cm) were retrospectively analyzed. In all patients a whole-body 18F-FDG PET/CT scan for initial staging was performed. The PET/CT findings were compared with all available clinical information, intra-operative findings and the histopathological results.

    Results: 95 patients (39 men, 56 women; age range, 19-85 years) were analyzed in our study.
    PET/CT in 68/95 patients correctly excluded mediastinal and distant metastases.
    In 17/95 patients (18%) mediastinal lymph-node metastases were proven (N2 n=15; N3 n=2). PET/CT correctly detected in 10/17 patients (58.8%) mediastinal nodal disease. The smallest mediastinal lymph-node metastasis detected by PET/CT had a size of 0.7cm. In 7 patients PET/CT missed N2-stage. In three of these patients the SUVmax of the primary was <1.9. In one patient the mediastinal metastasis had a size of 0.3cm. Only in one missed N2-stage metastasis was sized > 1.0cm. The tumor histology (adenocarcinoma, squamous cell carcinoma) and location of the primary (central, periphery) did not influence the missed N2-stage by PET/CT. PET/CT diagnosed correctly N3-stage in 2 patients
    10/95 patients (10.5%) had distant metastases. PET/CT detected unknown M1-stage in 4/10 patients. In one patient a metastasis of the parietal pleura was missed by PET/CT.

    Conclusion: In our study, 28% patients with T1-stage NSCLC showed mediastinal or distant metastases. PET/CT was efficient in the detection of occult metastases. However, the sensitivity of PET/CT in mediastinal staging was only 64%.