Biological features and preoperative evaluation of mediastinal nodal status in non-small cell lung cancer.

Background: To examine whether biological features of primary tumor can help preoperative evaluation of mediastinal nodal status in non-small cell lung cancer.
Methods: A total of 450 patients who underwent tumor resection and mediastinal dissection were reviewed. p53 status and proliferative fraction (PI) were evaluated immunohistochemically.
Results: The accuracy of preoperative evaluation of mediastinal nodal status with computed tomography (CT) was 72.2%; mediastinal nodal metastases had not been revealed until operation in 59 patients (13.1%) (false-negative), and no metastasis was revealed in 66 patients (14.7%) although mediastinal nodal enlargement had been demonstrated by CT (false-positive). The number of false-negative patients was significantly larger when p53 aberrant expression was positive or when PI was higher. Combined with p53 status and PI, there were 27 false-negatives (24.1%) among patients with aberrant p53 expression and higher PI, whereas only two false-negatives (1.5%) among those with negative p53 expression and lower PI.
Conclusions: Mediastinoscopy may be recommended for tumor showing aberrant p53 expression and higher PI, even when CT demonstrates no mediastinal nodal enlargement.