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S.H. Lo
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P2.03 - Poster Session/ Treatment of Locoregional Disease – NSCLC (ID 213)
- Event: WCLC 2015
- Type: Poster
- Track: Treatment of Locoregional Disease – NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.03-034 - Association of EGFR Mutation Status with Treatment Outcome in Stage III Non-small Cell Lung Cancer Patients Treated with Concurrent Chemoradiotherapy (ID 2723)
09:30 - 09:30 | Author(s): S.H. Lo
- Abstract
Background:
Epidermal growth factor receptor (EGFR) mutation is a biomarker predictive of favorable response to EGFR tyrosine kinase inhibitor in advanced non-small cell lung cancer (NSCLC). Its prognostic value in stage III NSCLC is unclear. The objective of this study is to analyze the association of EGFR mutation with clinical outcome in stage III NSCLC patients treated with concurrent chemoradiotherapy.
Methods:
91 consecutive patients with stage III non-small cell lung cancer who received concurrent chemoradiotherapy from January 2008 to January 2015 were retrospectively identified. EGFR mutation status was analyzed in 61 patients. Activated EGFR mutations were detected in 17 (28%) patients. Kaplan-Meier method was used to conduct the progression-free survival (PFS) and overall survival (OS) analyses. Univariate and multivariable analyses were performed to investigate the effects of predictor variables including age, disease stage, performance status, histology, EGFR mutation status, radiation dose and surgery after neoadjuvant chemoradiotherapy.
Results:
51 (56%) patients had stage IIIA and 40 (44%) patients had stage IIIB disease. All patients received at least 2 cycles of platinum-based chemotherapy. Majority (77%) of patients received radiation dose of 60Gy (range 50-66Gy). Among the 17 patients with activated EGFR mutation, 13(76%) of them had disease progression. 12 of them subsequently received EGFR TKI. The median progression-free survival (PFS) was 13.3 months. The median PFS was 12.3 months in patients with mutated EGFR compared with 15 months in patients with wild-type EGFR (log-rank p=0.33). However, in the subgroup analysis of non-squamous histology, there was no significance difference in PFS between patients with or without activated EGFR mutation (Median PFS 12.3 vs. 12.4 months; log-rank p=0.96). In the multivariable analysis with the Cox proportional hazard model, significant predictors of longer PFS include squamous cell histology (HR 0.3; 95% C.I. 0.09, 0.99; p=0.05) and surgery after chemoradiotherapy (HR 0.36; 95% C.I. 0.13, 0.95; p= 0.04). EGFR mutation status was not a significant predictor of PFS (P=0.45) The median overall survival (OS) was 28.6 months. The median OS in patients with mutated EGFR was 33 months while the median OS in patients with wild-type EGFR was 36.7 months (log-rank p=0.24). In the subgroup analysis of non-squamous histology, there was no significance difference in OS between patients with or without activated EGFR mutation (Median OS 33 vs. 31 months; log-rank p=0.65). In the multivariable analysis, significant predictors of longer OS include surgery after chemoradiotherapy (HR 0.16; 95% C.I. 0.04, 0.61; p=0.01), N-stage (p=0.04) and ECOG performance status (p=0.01). A trend of inferior OS was shown in patients with activated EGFR mutation compared with wild-type EGFR (HR 2.6; 95% C.I. 0.9, 7.64; p=0.08).
Conclusion:
In patients with stage III non-small cell lung cancer who received concurrent chemoradiotherapy, EGFR mutation status does not affect the progression-free survival. A trend of shorter overall survival was shown in patients with activated EGFR mutation, which was not statistically significant. This could be due to higher risks of distant metastasis in patients with EGFR mutation. The role of adjuvant EGFR TKI after chemoradiotherapy should be further investigated.
