Methods: Data of 1,226 patients (1,162 males, 64 females; mean age 56.8±7.5 years; range 26 to 81 years) who were performed mediastinoscopy for staging of NSCLC between April 1995 and May 2011 were retrospectively analyzed. The mean number of lymph node (LN) stations sampled, complications, and any false negative rate were recorded for lymph-node negative (cN0) patients who were performed thoracotomy. Patients were divided into three periods as between 1995 and 2001 (first period, n=295), between 2001 and 2006 (second period, n=316), and between 2006-2011 (last period, n=615).

Results: The mean number of LN stations sampled for each patient was 3.8±1.0 and there was a statistically significant difference between the periods (p<0.001). Statistically significantly more sampling was performed in the last period (n=4.0±0.8) compared to the first and second periods (n=3.4±1.3 and n=3.8±0.8, respectively) (p<0.001). Mediastinal LN metastasis was detected in a total of 224 patients (18.2%) with mediastinoscopy. False negativity was detected in 71 (8.1%) of 868 cN0 patients who underwent t horacotomy. False negative rate was higher in the first (n=28, 14.1%) and second periods (n=20, 8.6%) compared to the last period (n=23, 5.2%) (p<0.001). The prevalence of mediastinal lymph node metastasis tended to decrease over the years (p=0.08). Sensitivity, negative predictive value and accuracy were 0.66, 0.85, 0.89, respectively, for the first period; 0.74, 0.91, 0.93, respectively, for the second period; 0.83, 0.94 and 0.96, respectively, for the last period. The overall complication rate was 4% (n=49). There was no statistically significant difference between the periods in terms of complications (p=0.441). The most common complication was hoarseness (n=30, 2.4%). Mortality developed in a patient with pulmonary artery hemorrhage (0.08%).

Conclusion: According to our study results, the efficiency of mediastinoscopy in the staging of NSCLC increased in time. False negative rate decreased and true positivity increased as experience and number of sampled LN stations increased.