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B. Wang



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    JCES01 - Joint IASLC - Chinese Society for Clinical Oncology - Chinese Alliance Against Lung Cancer Session (ID 413)

    • Event: WCLC 2016
    • Type: Joint Chinese / English Session
    • Track:
    • Presentations: 1
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      JCES01.24 - Molecular Mechanism of Transformation from Adenocarcinoma to Small-Cell Lung Cancer after EGFR-TKI (ID 7066)

      B. Wang

      • Abstract
      • Slides

      Background:
      In patients with advanced non–small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) activating mutations, EGFR-tyrosine kinase inhibitors (TKIs) are recommended as first-line treatment due to favorable clinical efficacy. However, acquired resistance inevitably develops after median progression-free survival (PFS) of 9-14 months. Among the mechanisms of acquired resistance, small-cell lung cancer (SCLC) transformation was reported to account for nearly 5%. However, the molecular details underlying this histological change and resistance to EGFR-TKI therapy remain unclear.

      Methods:
      15 out of 233 (6.4%) patients were confirmed to develop SCLC transformation after failure to EGFR-TKI. We analyzed the clinical parameters of these patients by using chi-square test and Kaplan-Meier analysis. To explore gene alterations that might contribute to SCLC transformation, next generation sequencing (NGS) was performed on four pairs of matched pre- and post-transformation tumor tissue samples. We further performed NGS on 11 matched circulating tumor DNA (ctDNA) to explore the potential mechanism of resistance to EGFR-TKI.

      Results:
      The median age of SCLC transformed patients was 53 years. 93.3% (14/15) patients harbored EGFR exon19 deletion. The median PFS and overall survival (OS) of SCLC-transformed patients treated with EGFR-TKI compared to those without transformation were 11.7 versus 11.9 months (P=0.473) and 29.4 versus 24.3 months (P=0.664), respectively. All 4 patients developed loss of heterozygosity of TP53/RB1 after transformation. Besides, increased copy number of five proto-oncogenes were identified in post-transformation tissue samples. Three patients developed EGFR T790M mutation in the post-transformation ctDNA rather than their tissue samples.

      Conclusion:
      SCLC transformation was commonly seen in patients harboring EGFR exon 19 deletion. The clinical outcomes of TKI and OS in SCLC transformed patients were similar to non-transformed patients. The loss of heterozygosity of TP53 and RB1along with increased copy number of proto-oncogenes may lead to the SCLC transformation. The mechanisms of acquired resistance to TKI during SCLC transformation might be the emergence of classic drug resistance mutations, which was undetectable due to the intra-tumor heterogeneity.

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    MA08 - Treatment Monitoring in Advanced NSCLC (ID 386)

    • Event: WCLC 2016
    • Type: Mini Oral Session
    • Track: Advanced NSCLC
    • Presentations: 1
    • Now Available
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      MA08.07 - Prospective Sequential Counts of Total CTC or cKIT+CTC in Advanced NSCLC with 1st Line Chemotherapy (POLICE) (Now Available) (ID 5857)

      B. Wang

      • Abstract
      • Presentation
      • Slides

      Background:
      Circulating tumor cells (CTCs) have been reported prognostic and predictive in non-small cell lung cancer (NSCLC) and a few of other cancer types. In 1[st] line setting, whether EPCAM[+]CK[+]CD45[-] CTC and/or stem cell-like cKIT[+]EPCAM[+ ]CK[+]CD45[-] CTC enumeration and dynamic changes can be prognostic and/or predictive to standard chemotherapy need further investigation in Chinese patients with NSCLC.

      Methods:
      A prospective study on the CTC enumeration in advanced NSCLC with 1st line chemotherapy (POLICE) was started by China Thoracic Oncology Group (CTONG). Patients with NSCLC naïve for systemic regimens were enrolled since August 2013. CTCs were detected by Cell Search Platform and identified as positive for EPCAM[+]CK[+]CD45[-] phenotype. CD117 (cKIT) marker was added to test the frequency of stem cell-like cKIT[+]EPCAM[+]CK[+]CD45[- ]CTCs. Primary endpoints were CTC counts and its correlation with first line therapy.

      Results:
      Totally 180 patients were enrolled. In 174 case total CTC and cKIT[+]CTC positive (cutoff >=1) rates were 38.5% (67/172) vs 14.3% (24/168), 21.8% (31/142) vs 6.3% (9/142), 13.7% (13/95) vs 6.4% (6/94) and 40.4% (38/94) vs 15.0% (13/93) at time-points of baseline, after first-cycle-chemo, after four-cycles-chemo and disease progression. At time immediately after first-cycle-chemo, patients in CTC=0 group got statistically higher ORR (29.0% VS 7.1%, P=0.017) and DCR (74.2% VS 42.9%, P=0.002) than in CTC>=1 group. At time after four-cycles-chemo, patients in CTC=0 group got statistically higher DCR (88.3% VS 58.3%, P=0.026) than in CTC>=1 group. At time either after first-cycle-chemo or after four-cycles-chemo, patients in CTC>=1 group got worse PFS (5.7m VS 4.0m, P=0.025; 6.3m VS 4.0m, P=0.001 ) than in CTC=0 group. At time after first-cycle-chemo, patients in groups cKIT[+]CTC>=1 and cKIT[-]CTC>=1 got worse PFSs (3.1m vs 4.0m vs 5.7m, P=0.001) and worse DCRs (44.4% vs 42.1% vs 73.9%, P=0.009) than in CTC=0 group. For 142 patients categorized into three groups of dynamic CTC decrease (17), CTC unchanged (82), and CTC increase (43), there were significant differences in terms of DCR (71.8% vs 71.6% vs 33.3%, P=0.018) and PFS (5.2m vs 5.6m vs 3.1m, P=0.037).

      Conclusion:
      In first line setting of advanced NSCLC, at time-points after first-cycle-chemo other than baseline, total CTC or cKIT[+]CTC counts could be predictive for worse DCR or PFS. CTC increase from baseline to after-first-cycle-chemo might be a strong signal for the inefficacy of first line chemotherapy in the NSCLC patients.

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    P3.02b - Poster Session with Presenters Present (ID 494)

    • Event: WCLC 2016
    • Type: Poster Presenters Present
    • Track: Advanced NSCLC
    • Presentations: 1
    • Now Available
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      P3.02b-116 - Molecular Mechanism of Transformation from Adenocarcinoma to Small-Cell Lung Cancer after EGFR-TKI (Now Available) (ID 4983)

      B. Wang

      • Abstract
      • Slides

      Background:
      In patients with advanced non–small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) activating mutations, EGFR-tyrosine kinase inhibitors (TKIs) are recommended as first-line treatment due to favorable clinical efficacy. However, acquired resistance inevitably develops after median progression-free survival (PFS) of 9-14 months. Among the mechanisms of acquired resistance, small-cell lung cancer (SCLC) transformation was reported to account for nearly 5%. However, the molecular details underlying this histological change and resistance to EGFR-TKI therapy remain unclear.

      Methods:
      15 out of 233 (6.4%) patients were confirmed to develop SCLC transformation after failure to EGFR-TKI. We analyzed the clinical parameters of these patients by using chi-square test and Kaplan-Meier analysis. To explore gene alterations that might contribute to SCLC transformation, next generation sequencing (NGS) was performed on four pairs of matched pre- and post-transformation tumor tissue samples. We further performed NGS on 11 matched circulating tumor DNA (ctDNA) to explore the potential mechanism of resistance to EGFR-TKI.

      Results:
      The median age of SCLC transformed patients was 53 years. 93.3% (14/15) patients harbored EGFR exon19 deletion. The median PFS and overall survival (OS) of SCLC-transformed patients treated with EGFR-TKI compared to those without transformation were 11.7 versus 11.9 months (P=0.473) and 29.4 versus 24.3 months (P=0.664), respectively. All 4 patients developed loss of heterozygosity of TP53/RB1 after transformation. Besides, increased copy number of five proto-oncogenes were identified in post-transformation tissue samples. Three patients developed EGFR T790M mutation in the post-transformation ctDNA rather than their tissue samples.

      Conclusion:
      SCLC transformation was commonly seen in patients harboring EGFR exon 19 deletion. The clinical outcomes of TKI and OS in SCLC transformed patients were similar to non-transformed patients. The loss of heterozygosity of TP53 and RB1 along with increased copy number of proto-oncogenes may lead to the SCLC transformation. The mechanisms of acquired resistance to TKI during SCLC transformation might be the emergence of classic drug resistance mutations, which was undetectable due to the intra-tumor heterogeneity.

      Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.