Evaluation of the TN sub-staging in patients with initially unresectable stage III non-small cell lung cancer treated by induction chemotherapy. The European Lung Cancer Working Party.

PURPOSE: This study attempted to investigate, in a cohort of patients with clinical stage III initially unresectable non-small cell lung cancer (NSCLC) treated by the same induction chemotherapy regimen, the prognostic value of clinical T and N sub-groupings in order to validate the current International Staging System (ISS).

PATIENTS AND METHODS: All the eligible patients with stage III NSCLC (428 patients) registered in a clinical trial were included in the study investigating, after three courses of induction chemotherapy, the role, in responders, of chest irradiation in comparison to further chemotherapy. The chemotherapy regimen consisted of mitomycin C, ifosfamide and cisplatin.

RESULTS: Patients with ISS 1986 stage IIIA had a significantly better survival than those with stage IIIB (median survival 47 vs 36 weeks; P = 0.01). A RECPAM analysis showed that patients with T1-T2 N3 and T4 N0-1-2 stage had a more similar prognosis to those with stage IIIA. That result leads to define two new sub-groups: stage IIIlalpha (T3-T4 N0-N1; any T N2; T1-T2 N3) and IIIbeta (T3-T4 N3), with a highly significant difference in survival between them (median survival: 45 vs 29 weeks; P < 0.0001). The superiority of that new classification on the ISS documented in our series of stage III patients for discriminating survival and tumour response has to be confirmed on another series in a multivariate context.

CONCLUSION: For unresectable NSCLC treated by induction chemotherapy, stage III sub-classification by moving T4 N0-1 and T1-2 N3 tumours from stage IIIB to stage IIIA appeared to better correlate with prognosis. The usefulness of this new sub-division has to be tested in validation studies.