Diagnostic accuracy of PET/CT in multimodality mediastinal staging of NSCLC

Objectives Staging lung cancer patients by means of PET/CT reduces the number of futile thoracotomies. A significant factor for treatment possibilities is the status of mediastinal lymph nodes since N2-N3 disease excludes the patient from primary surgery. We present prospective clinical data describing the faults and benefits of mediastinal staging by PET/CT.

Methods Patients with operable non-small cell lung cancer (NSCLC) were prospectively recruited and randomly assigned to staging with or without PET/CT. N-stage was described according to CT, PET/CT, mediastinoscopy, EUS-FNA, consensus (based on all available information) and compared to the final N-stage as assigned by thoracotomy or invasive diagnostic procedure. The diagnostic accuracy of each modality as well as the consensus stage dichotomizing N-stage into N0-1 versus N2-3 was estimated.

Results 189 patients were recruited, of these 168 patients were assessable, 79 in the PET/CT group and 89 in the control group. Within the PET/CT group, PET/CT was more accurate than CT alone with a diagnostic accuracy of 77% versus 62%. The overall accuracy of the consensus N-stage was significantly higher in the PET/CT group than in the control group (95% versus 85%). This was mainly based on a higher sensitivity of the staging approach with PET/CT (85% versus 59%). Performance of PET/CT was related to localization of the primary tumor and size of the lymph nodes.

Conclusions Based on data from a randomized clinical trial we conclude that a staging approach with PET/CT results in a more accurate discrimination between N0-1 and N2-3, leading to a better designation of operability in patients with NSCLC.

Research Support Danish Cancer Societ