Background: Biopsies by mediastinoscopy remain the most reliable preoperative staging method for N2 lung cancer. Because it is neither practical nor economical to recommend mediastinoscopy for all candidates for surgery, we developed indicational criteria for video-assisted mediastinoscopy (VAM) and carried out a prospective study to validate its usefulness.
Methods: Patients with resectable primary lung cancer were chosen for VAM when at least one of three clinical indicators was present: (1) computed tomographic evidence of mediastinal adenopathy, (2) elevated levels of serologic tumor markers, and (3) diameters of primary cancers (> 2 to 3 cm). Patients without positive nodes (group 2) underwent thoracotomy, and patients with positive nodes (group 3) received induction therapy. When none of these criteria were met (group 1), thoracotomy with R2b lymph node dissection was performed without VAM.
Results: One hundred twenty-one men and 82 women (total, 203) were eligible for the study. The mean age of the patients was 64.4 years (range, 39 to 75 years) with primary lung cancer. The patients were comprised of 135 adenocarcinomas, 46 squamous cell cancers, and 22 other carcinomas. There were 78 patients in group 1, 87 in group 2, and 38 in group 3. The stages of group 2 patients were more advanced (chi2 = 63.2668; p < 0.001) than those of group 1. As the incidence of positive indicators for VAM increased, the ratios of N2 patients increased from 2.5% (all negative) to 90.4% (triple positive: p < 0.001). The correlation of our criteria with the pathology findings revealed a diagnostic sensitivity of 95.8% and a negative predictive value of 97.4%. Using three indicators for N2 prediction, we selected 96% (46 of 48) pN2, N3 patients and avoided 37% (76 of 203) unnecessary VAMs.
Conclusions: We established and validated currently useful criteria for VAMs in the management of primary lung cancer.