Comparison of Outcomes for Patients With Unresectable, Locally Advanced Non-Small-Cell Lung Cancer Treated With Induction Chemotherapy Followed By Concurrent Chemoradiation vs. Concurrent Chemoradiation Alone

Purpose: To retrospectively compare outcomes for patients with unresectable locally advanced non-small-cell lung cancer (NSCLC) treated at our institution with concurrent chemoradiation with or without induction chemotherapy. Methods and Materials: We retrospectively analyzed 265 consecutive patients who received definitive treatment with three-dimensional conformal radiation and concurrent chemotherapy. Of these, 127 patients received induction chemotherapy before concurrent chemoradiation. Results: The two groups of patients (with induction vs. without induction chemotherapy) were similar in age, performance status, weight loss, histology, grade, and stage. Patients who received induction chemotherapy had better overall survival (median, 1.9 vs. 1.4 years; 5-year rate, 25% vs. 12%; p < 0.001) and distant metastasis-free survival (5-year rate, 42% vs. 23%; p = 0.021). Locoregional control was not significantly different between the two groups. Multivariate analysis showed that induction chemotherapy was the most significant factor affecting overall survival, with a hazard ratio of 0.55 (95% confidence interval 0.40-0.75; p < 0.001). A planned subgroup analysis showed that induction chemotherapy was associated with a significant overall survival benefit for patients with adenocarcinoma or large-cell carcinoma (5-year rate, 24% vs. 8%; p = 0.003) but not for those with squamous cell carcinoma. A multivariate analysis of patients with adenocarcinoma or large-cell carcinoma confirmed that induction chemotherapy was the most significant factor associated with better overall survival, with a hazard ratio of 0.47 (95% confidence interval, 0.28-0.78; p = 0.003). Conclusion: Our retrospective analysis suggests that in combination with concurrent chemoradiation, induction chemotherapy may provide a small but significant survival benefit for patients with unresectable locally advanced adenocarcinoma or large-cell carcinoma of the lung.