The accuracy and cost of mediastinal staging strategies for non-small cell lung cancer

Background: To compare the accuracies and costs of some strategies including positron emission tomography (PET) and cervical mediastinoscopy (CM) in the mediastinal staging of non-small cell lung cancer (NSCLC) was aimed. Methods: Thoracic computed tomography (CT) and PET was performed in 197 patients (177 males, 20 females; mean age 60.2 years; range 30 to 84 years) diagnosed with operable NSCLC between November 2004 and February 2007. Cervical mediastinoscopy was performed in all patients. Mediastinal lymphatic metastases (MLM) were detected in 48 patients, and these patients were directed to chemo-radiotherapy. The remaining 149 patients underwent lung resection and systematic mediastinal lymphatic dissection via thoracotomy was performed. The mediastinal lymph nodes were histopathologically examined. The sensitivity, specificity, and accuracy rates of PET and CM to detect MLM were calculated. Three mediastinal staging strategies, including PET and CM, were designed and the results of these 197 patients were adapted into these strategies. Strategy A; designed as to take PET scan from all patients and to perform CM to only patients with mediastinal uptake reported in their PET scan. Strategy B (selective PET-selective CM); was created as to take PET scan from patients with NSCLC staged as T1N0 according to their CT, if no mediastinal uptake reported, performing thoracotomy without prior CM, and to perform CM to all other, PET scan had not been taken patients. Strategy C (high-selective CM); was designed as to perform directly thoracotomy without another staging procedure to patients with cancer in squamous cell type, located peripherally and staged as T1N0, acconling to their CT, and to perform CM to all other patients. The accuracy and the average cost according to the prices established by Social Security Organization of Turkey of each strategy were calculated. Results: The sensitivity, specificity, and accuracy rates of PET were determined as 73%, 75%, and 74%, respectively while sensitivity, specificity, and accuracy rates of CM were determined as 81%, 100%, and 94%, respectively. If strategy A that include to take PET scan from all patients had been followed up, sensitivity, negative predictive value (NPV) and accuracy rates that would be obtained were determined as 66%, 87% and 90%, respectively, and total cost that would be occurred was calculated as 332.330 TL. If B strategy had been applied, sensitivity, NPV and accuracy rates would increase as 81%, 93% and 94%, respectively, and total cost would decrease to 164.830 TL. If strategy C had been followed, sensitivity, NPV and accuracy rates would be same but total cost would slightly decreased (140.250 TL) when compared with B strategy. Conclusion: In mediastinal staging of lung cancer, sufficient accuracy rate could not been obtained when the staging strategy being as to take PET scan from all patients, and to perform CM to only patients with mediastinal uptake reported in their PET scan, furthermore, this strategy causes high cost. But, strategies include selective using of PET and CM can be applied with satisfactory accuracy rates and acceptable costs.