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S. Ahn
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P2.05 - Poster Session with Presenters Present (ID 463)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Radiotherapy
- Presentations: 1
- Moderators:
- Coordinates: 12/06/2016, 14:30 - 15:45, Hall B (Poster Area)
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P2.05-037 - Higher Radiation Dose is Still Promising in Patients with Complete Response to 50 Gy of Early Thoracic Radiotherapy with Chemotherapy? (ID 4226)
14:30 - 14:30 | Author(s): S. Ahn
- Abstract
Background:
For limited stage small cell lung cancer (LSCLC), early thoracic radiotherapy (TRT) with chemotherapy and radiation dose more than 60Gy has been suggested as standard therapy. We aim to evaluate the survival outcomes in LSCLC patients with complete response (CR) to 50 Gy of TRT with chemotherapy.
Methods:
One hundred and fifteen patients with LSCLC who completed the TRT from August 2005 to March 2014 were reviewed retrospectively. We evaluated the age, gender, smoking status, AJCC stage, PET parameters, tumor volume, dose and timing of TRT, duration of treatment, and prophylactic cranial irradiation (PCI) as a prognostic variables. Gross tumor volume (GTV) was defined as the post-chemotherapy tumor volume at the time of the first TRT planning and the pre-chemotherapy involved lymph nodes. Clinical target volume (CTV) was defined as GTV with minimum 7mm margin including the first echelon drainage lymph node station. At the time of 50 Gy of TRT, follow up chest CT was performed to all patient and only patients who showed non-CR received 10 Gy or more radiation. Dose of TRT was median 50 Gy (range, 42 to 65 Gy). Ninety-seven (84.3%) patients received concurrent chemoradiotherapy (CRT) and PCI was performed in all eligible patients.
Results:
For all patients, median survival was 27.8 months. Two & 3-year OS were 60.7% and 38.58%, respectively. Sixty-five patients (56.5%) showed the complete response (CR) and fifty patients (43.5%) showed non-CR. There was correlation between tumor response to 50Gy of TRT and the ratio of GTV to CTV (p=0.008) or AJCC stage (p=0.036). With univariate analysis, AJCC stage (p<0.001), ratio of GTV to CTV (p = 0.005), tumor response to 50Gy of TRT (p = 0.004), the duration from the start date of induction chemotherapy to the end of TRT (SER, p = 0.003), and PCI (p = 0.035) were statistically significant predictor of OS. Multivariate Cox regression demonstrated that AJCC stage (p<0.001) and SER (p = 0.007) only were significant. In patients with SER <80days & CR to 50Gy TRT, median survival was not yet reached until now.
Conclusion:
LSCLC patients who showed CR to 50 Gy of TRT and completed TRT within 80days represented the outstanding survival outcomes. Based on these results, we need the further study evaluating whether dose escalation more than 50 Gy is promising for survival improvement in patients with CR at the time of 50 Gy of early TRT and chemotherapy.
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P3.02b - Poster Session with Presenters Present (ID 494)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Advanced NSCLC
- Presentations: 2
- Moderators:
- Coordinates: 12/07/2016, 14:30 - 15:45, Hall B (Poster Area)
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P3.02b-018 - Detection of Epidermal Growth Factor Receptor Mutations in Circulating Cell-Free DNA versus Tumor Biopsy (ID 5550)
14:30 - 14:30 | Author(s): S. Ahn
- Abstract
Background:
Epidermal growth factor receptor (EGFR) mutations are predictive marker of EGFR-tyrosine kinase inhibitor (TKI) therapy. We compared the sensitivity of EGFR mutation detection techniques between matched tumor tissue and peripheral blood sample in patients with lung adenocarcinoma.
Methods:
We collected the paired samples from plasma and paraffin-embedded tumor tissue in 202 patients before EGFR-TKIs. DNA extraction was performed using the QIAamp MinElute virus spin kit and EGFR mutation analysis was done by two detection methods. One is the PNAClamp[TM] which is the PNA-based PCR clamping that selectively amplifies only the mutated target DNA sequence as minor portion in mixture with the major wild type DNA sequences. The other is the PANAMutyper[TM] EGFR kit, which use PNA clamping-assisted fluorescence melting curve analysis to perform mutation detection and genotyping. The degree of agreement was evaluated by Cohen's kappa value.
Results:
The EGFR mutation rates by PANAMutyper[TM]R and PNAClamp[TM] were 51.0% vs. 47.0% in tissue, and 22.2% vs. 11.4% in plasma sample, respectively. Overall concordance rates and the degree of agreement between tissue and plasma samples was better in PANAMutyper[TM]R (69.3%, k=0.393, p<0.001) than PNAClamp[TM] (62.3%, k=0.211, p<0.001). Sensitivity of plasma EGFR mutations was higher (41.7% vs. 22.1%, p<0.001) and false negative rate was lower in PANAMutyper[TM]R test (58.3% vs. 77.9%, p<0.001). Response to EGFR-TKI was correlated with plasma EGFR mutation by PANAMutyper[TM]R (p=0.025) unlike PNAClamp[TM ](p=0.829).
Conclusion:
The sensitivity and concordance rate of PANAMutyper[TM]R test were better than standard PNAClamp[TM] test. So this technique can be useful to detect EGFR mutation in circulating cell-free DNA sample.
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P3.02b-112 - Feasibility of Re-Biopsy in Patients with Non-Small Cell Lung Cancer after Failure of Epidermal Growth Factor Receptor Targeted Therapy (ID 5557)
14:30 - 14:30 | Author(s): S. Ahn
- Abstract
Background:
After failure of epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), re-biopsy may be helpful to understand resistance mechanism and guide further treatment decision. However, re-biopsy is still challenging due to several hurdles, such as tissue availability, procedural feasibility, and limited new drugs. The aim of this study was to assess the feasibility of re-biopsy in advanced non-small cell lung cancer (NSCLC) in a real-practice.
Methods:
We retrospectively reviewed the clinical and pathologic data of advanced NSCLC patients who had disease progression after previous EGFR-TKI at single institution between January 2015 and February 2016.
Results:
Ninety-one patients had disease progression after using EGFR-TKI. Among them, thirty-three patients (36.3%) underwent re-biopsy. re-biopsy was successfully completed for thirty-two patients (97.0%) and only one patient didn’t get malignant cell. Three patients (9.1%) experienced a pneumothorax, however only one patient required closed thoracostomy. After re-biopsy, 27 patients were performed EGFR mutation test. Among 21 patients who had active mutation, the initial mutation was again found in 9 cases (42.9%) while the T790M mutation was found in 6 cases (28.6%). In 4 cases the initial EGFR mutation was no longer found. The patients who had re-biopsy were younger (61.2±9.7 vs. 66.1±10.8 years, p=0.03) and longer response duration (429±383 vs. 265±284 days, p=0.022) than the patients who didn’t.
Conclusion:
Re-biopsy in advanced NSCLC is feasible in the real practice especially in younger patient and patients with longer response duration of EGFR-TKI.
