Pathologic complete response as independed prognostic factor after induction therapy followed by surgery in locally advanced non-small cell lung cancer

Introduction: Pathological complete response (pCR) after induction chemoradiation therapy (CRT) and followed by surgery in locally advanced non-small cell lung cancer (NSCLC) is associated with favorable long-term survival (LTS). The implication of pCR to daily clinical practice is yet poorly defined. The aim of the study was to identify the correlation of pCR and different prognostic factors influencing long-term survival (LTS), tumor recurrence pattern and progressive-free interval (PFI).

Material and methods: A cohort patients with locally advanced stage III NSCLC treated with induction chemoradiation (CRT) and subsequent surgery at a single center was retrospective reviewed. The subgroup of patients with pCR after the initial CRT was selected for further analysis. The statistical analysis stratified by descriptive statistics, Kaplan-Meier survival curves and estimated 3- and 5-years survival time combined with long-rank tests and Cox multivariate-analysis.

Results: Between March 2008 and November 2015, a total of 22 patients with proven pCR were included in the retrospective analysis. The mean age was 59 ± 9.5 years. Thirteen patients (72%) were younger than 65. The median radiation dose applied was 50.4 Gy (range 45 – 56 Gy). The mean interval between the induction therapy and operation was 7.4 ± 3.3 weeks and complete (R0) resection was achieved in all 20 (91%) patients. The prognostic influence of gender, age, initial tumor stage and grade, histological subtype and operation type on pCR was analyzed using log-rank test and multivariate Cox regression model. The estimated 3- and 5-year survival rates for LTS were 64% and 57%, respectively. The estimated 3- and 5-year rates for PFI were 55% and 46%, respectively.

Conclusion: Favorable LTS is associated with pCR after CRT and followed by curative surgical resection. During the analysis pCR was identified as an independent prognostic factor. The distant tumor control remains the main limiting factor for LTS.