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Y.C. Ahn



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    MA06 - Locally Advanced NSCLC: Risk Groups, Biological Factors and Treatment Choices (ID 379)

    • Event: WCLC 2016
    • Type: Mini Oral Session
    • Track: Locally Advanced NSCLC
    • Presentations: 1
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      MA06.03 - Recurrence Dynamics after Trimodality Therapy (Neoadjuvant Chemoradiotherapy and Surgery) in Stage IIIa(N2) Lung Cancer (ID 4963)

      16:12 - 16:18  |  Author(s): Y.C. Ahn

      • Abstract
      • Presentation
      • Slides

      Background:
      In IIIa(N2) Non-small cell lung cancer (NSCLC), various strategies to cure have been tried but the major cause of mortality is still the recurrence. Therefore, understanding of the dynamics of recurrence is important to improve the treatment outcome. We investigated the timing and patterns of recurrence after treatment of IIIA(N2) NSCLC with trimodality treatment (neoadjuvant chemoradiotherapy and surgery).

      Methods:
      An institutional database of consecutive patients between 1997 and 2013 (N = 574) was reviewed retrospectively. Eligible patients had pathologically proven N2 disease of NSCLC and completion of a planned trimodality treatment. First events involving the development of loco-regional recurrence, distant metastases or both were considered. The hazard rate function was used to evaluate the dynamics of recurrence.

      Results:
      The 5-year overall survival rate was 47% and the 5-year recurrence free survival rate was 29%. Among the 299 patients (52.1% of total) who experienced recurrence, 26 (8.7%) had loco-regional recurrences, 248 (82.9%) had distant metastases, and 25 (8.4%) had both. The most frequent sites of distant metastases were lung (n=102, 41%), brain (n=63, 25%), and bone (n=63, 25%). The hazard rate function for the overall recurrence revealed the peak at approximately 8 months after surgery then the down-slope pattern before 38 months. A similar risk pattern was found in distant metastasis but low and steady risk pattern was detected in loco-regional recurrence. In distant metastases, similar patterns were found in individual organs, however, earlier peak at approximately 5 months presented in brain metastasis. A comparison of histology showed that adenocarcinoma exhibited higher recurrence hazard rate of distant metastasis than squamous cell carcinoma with similar pattern of recurrence (p=0.03). The status of nodal clearance after induction therapy exhibited that ypN2 patients (n= 229, 39.9%) had highest hazard rate (p=0.03). The recurrence hazard rate of ypN0 was the least, but the extent was not smaller, they showed approximately one of third of ypN2 at peak.

      Conclusion:
      The hazard rate of loco-regional failure after trimodality therapy was low. But the hazard rate of distant metastasis was considerably high yet and shifted to left with the peak within 12 moths after surgery. This study guides the intensive surveillance immediate after completion of trimodality therapy to identify risk groups of early recurrence and to develop therapeutic strategy.

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    P2.02 - Poster Session with Presenters Present (ID 462)

    • Event: WCLC 2016
    • Type: Poster Presenters Present
    • Track: Locally Advanced NSCLC
    • Presentations: 1
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      P2.02-044 - Impact of N2 Extent and Nodal Response on Survival after Trimodal Treatment for Stage IIIA-N2 Non-Small Cell Lung Cancer (ID 4662)

      14:30 - 14:30  |  Author(s): Y.C. Ahn

      • Abstract
      • Slides

      Background:
      Mediastinal nodal downstaging is an important prognostic factor of neoadjuvant concurrent chemoradiotherapy (CCRT) for stage IIIA-N2 non-small cell lung cancer (NSCLC) and the role of trimodal treatment remains controversial in patients with persistent N2 disease. We aimed to investigate survival outcomes based on the extent of pre-CCRT nodal involvement and mediastinal nodal response in patients who underwent neoadjuvant CCRT for stage IIIA-N2 NSCLC.

      Methods:
      A retrospective review of patients with N2 disease who underwent neoadjuvant CCRT followed by surgery at our institution was performed and survival outcomes were compared according to the extent of pre-CCRT mediastinal nodal involvement and mediastinal nodal response to CCRT. Extensive lymph node involvement was defined by short-axis diameter of lymph nodes > 2cm measured at computed tomography or involvement of 2 or more mediastinal lymph node stations.

      Results:
      From 2003 to 2013, 407 patients underwent curative-intent surgery after neoadjuvant CCRT for NSCLC with pathologically proven N2 disease. The mean age was 59 years (314 men, 77%) and histologic type included adenocarcinoma in 233 patients (57%), squamous cell carcinoma in 141 (35%), and large cell carcinoma in 11 (2.7%). Seventy-nine patients (19%) had extensive N2 disease on pre-CCRT imaging tests. The extent of surgery included lobectomy in 311 patients (76%), pneumonectomy in 43 (11%), and sleeve resection in 15 (3.7%). Post-CCRT pathologic nodal status was ypN0 in 155 patients (38%), ypN1 in 56 (14%), and ypN2 in 196 (48%). With a mean follow-up of 41 months, median overall survival (OS) and recurrence-free survival (RFS) were 73 months and 18 months, respectively. The 5-year OS and RFS rates were 61% and 42% in ypN0-1 and 40% and 13% in ypN2, respectively (OS, p=0.0032; RFS, p<0.0001). For patients with ypN0-1, the 5-year OS and RFS rates were 60% and 52% in extensive N2 disease and 61% and 40% in non-extensive N2 disease, respectively (OS, p=0.8106; RFS, p=0.1218). For patients with ypN2, the 5-year OS and RFS rates were 22% and 12% in extensive N2 disease and 47% and 12% in non-extensive N2 disease, respectively (OS, p=0.0403; RFS, p=0.4842).

      Conclusion:
      Pre-CCRT non-extensive N2 disease was associated with better OS, but was not with better RFS in patients with persistent N2 disease. Patients who achieved mediastinal downstaging showed acceptable OS and RFS regardless of N2 extensiveness. Considering heterogeneity of N2, the indication of neoadjuvant CCRT needs to be differentiated according to the extent of pre-CCRT nodal involvement and post-CCRT mediastinal nodal response.

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    P2.05 - Poster Session with Presenters Present (ID 463)

    • Event: WCLC 2016
    • Type: Poster Presenters Present
    • Track: Radiotherapy
    • Presentations: 1
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      P2.05-023 - Patterns of Failure after Adjuvant Radiation Therapy Based On "Tumor Bed with Margin" for Stage III Thymic Epithelial Tumor (ID 6352)

      14:30 - 14:30  |  Author(s): Y.C. Ahn

      • Abstract
      • Slides

      Background:
      This study was conducted to assess optimal radiation target volume in patients with locally advanced thymic epithelial tumor (TET) treated by surgery and postoperative radiation therapy (PORT).

      Methods:
      The records of 54 patients with Masaoka-Koga stage III TET, who received surgical resection at Samsung Medical Center, from Jan. 2000 to Dec. 2014, were retrospectively reviewed. The most common TNM stage was T3N0M0 (n=46, 85.2%) according to the new staging system proposed by the International Association for the Study of Lung Cancer and the International Thymic Malignancy Interest Group. The median PORT dose was 54 Gy in 27 fractions. Target volume was confined to the primary tumor bed only, while did not include the regional lymphatics nor pleuro-pericardial space electively. The clinical outcomes, prognostic factors and patterns of failure were analyzed.

      Results:
      After median follow-up of 62 months, there were 19 (35.2%) patients who had disease recurrence. Pure local failure within the PORT volume was founded in only one (1.9%) patient who had gross residual mass after surgery, pleuro-pericardial seeding in 5 (9.3%), distant metastases in 10 (18.5%), and regional recurrence in adjacent mediastinum or lymph nodes in 3 (5.6%) patients with WHO type B3 or C TET. Overall survival rate at 5 and 10 years was 83.0% and 43.6%, respectively. Recurrence free survival rate at 5 and 10 years was 62.3% and 57.9%, respectively. The age <60 years old, female gender, and tumor diameter <10 cm were favorable prognostic factors for overall survival on univariate analyses. Radiation toxicity was mild in most patients and no severe toxicity was registered.

      Conclusion:
      PORT confined to the primary tumor bed only is suggested to be optimal in patients with Masaoka stage III (T1b-4N0) TET considering excellent in-field control and minimal out-field regional recurrences. Development of effective systemic treatment strategy to reduce the pleuro-pericardial seeding may be warranted.

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