Pathologic complete response to preoperative chemotherapy predicts cure in early-stage non-small-cell lung cancer: combined analysis of two IFCT randomized trials.

Introduction: Our study aimed to evaluate whether pathologic complete response (pCR) in early-stage non-small-cell lung cancer (NSCLC) after neoadjuvant chemotherapy resulted in improved outcome, and to determine predictive factors for pCR.
Methods: Eligible patients with stage-IB or -II NSCLC were included in two consecutive Intergroupe Francophone de Cancérologie Thoracique phase-III trials evaluating platinum-based neoadjuvant chemotherapy, with pCR defined by the absence of viable cancer cells in the resected surgical specimen.
Results: Among the 492 patients analyzed, 41 (8.3%) achieved pCR. In the pCR group, 5-year overall survival was 80.0% compared with 55.8% in the non-pCR group (p = 0.0007). In multivariate analyses, pCR was a favorable prognostic factor of overall survival (relative risk = 0.34; 95% confidence interval = 0.18-0.64) in addition to squamous-cell carcinoma, weight loss less than or equal to 5%, and stage-IB disease. Five-year disease-free survival was 80.1% in the pCR group compared to 44.8% in the non-pCR group (p < 0.0001). Two patients (4.9%) in the pCR group experienced disease recurrence compared to 193 patients (42.8%) in the non-pCR group. SCC subtype was the only independent predictor of pCR (odds ratio [OR] = 4.30; 95% confidence interval = 1.90-9.72).
Conclusion: Our results showed that pCR after preoperative chemotherapy was a favorable prognostic factor in stage-IB-II NSCLC. Our study is the largest published series evaluating pCRs after preoperative chemotherapy. The only factor predictive of pCR was squamous-cell carcinoma. Identifying molecular predictive markers for pCR may help in distinguishing patients likely to benefit from neoadjuvant chemotherapy and in choosing the most adequate preoperative chemotherapy regimen.