Nodal downstaging predicts survival following induction chemotherapy for stage IIIA (N2) non-small cell lung cancer in CALGB protocol #8935

Background and Objectives: CALGB 8935 was a phase II protocol for mediastinoscopically staged IIIA (N2) non-small cell lung cancer. Induction cisplatin/vinblastine chemotherapy was followed by surgical resection, adjuvant cisplatin/vinblastine, and radiotherapy. We now evaluate the prognosis of pathologic nodes. Methods: Failure-free survival was calculated from a landmark 3 months after resection to account for heterogeneity in adjuvant therapy. Results: Nine of 42 (21%) resected patients had no residual N2 disease. This subset of 9 had a median failure-free interval of 47.8 months from landmark, whereas the 33 patients (79%) with persistent N2 disease had a median failure-free survival of 8.2 months from landmark (P = 0.01). Although 21/42 (50%) had an incomplete resection (positive highest resected node and/or margin), completeness of resection did not influence failure-free survival. There were 3 distant and no local recurrences among the N2 negative group, and 12 local recurrences among patients with residual N2 disease (P = 0.041). Conclusions: These data suggest: (1) persistent N2 disease following induction chemotherapy is unfavorable; (2) patients downstaged to N2 negative may benefit from surgical resection; however, (3) 33% of N2 negative patients suffered disease relapse.