[Neoadjuvant therapy in non-small cell lung cancer. Prognostic impact of "mediastinal downstaging"].

In the course of a prospective multicenter study, 40 (26 squamous cell and 14 adenocarcinomas) patients with stage IIIA and IIIB non-small cell lung cancer (NSCLC) were submitted to surgery after neoadjuvant radiochemotherapy. Pretherapeutic clinical lymph node status was compared to the lymph node involvement established in the resection specimens. Therapy-induced tumor regression was classified according to a three-step tumor regression grading system. In 29 patients (72.5%) a downward shift in lymph node involvement could be established,whereas in 27.5% ( n=11) pretherapeutic lymph node status was maintained. Of 26 patients with post-therapeutic N0 or N1 status, 21 revealed less than 10% vital tumor tissue in the resection specimens (regression grades IIb or III). Patients with post-therapeutic N0 or N1 lymph node status were found to have a survival benefit compared to patients with N2 lymph node involvement, though this difference was not statistically significant (p=0.27). On the other hand, tumor regression showed a significant correlation to the overall survival period (p=0.02). Thus, therapy-induced tumor regression grading seems to be a more precise method to predict the outcome of the disease.