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W. Mao



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    MA 09 - The Current Status of Radiation Oncology (ID 666)

    • Event: WCLC 2017
    • Type: Mini Oral
    • Track: Locally Advanced NSCLC
    • Presentations: 1
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      MA 09.01 - A Propensity-Matched Analysis of Lobectomy and Stereotactic Body Radiotherapy for Early Stage Non-Small Cell Lung Cancer (ID 10452)

      11:00 - 12:30  |  Author(s): W. Mao

      • Abstract
      • Presentation
      • Slides

      Background:
      Lobectomy is the preferred treatment for patients with early stage non-small cell lung cancer (NSCLC). However, stereotactic body radiation therapy (SBRT) is an attractive option due to its promising efficacy reported recently. Given that prospective comparative data on lobectomy and SBRT are limited, we compared the two treatments for early stage NSCLC.

      Method:
      All patients undergoing treatment with lobectomy or SBRT for clinical early stage (T size≤5cm) NSCLC between January 2012 and June 2017 were reviewed. Age, gender, tumor characteristics, Charson Comorbidity Index, pulmonary function, local control rate (LCR), recurrence-free survival (RFS), overall survival (OS) data were collected and propensity matching performed.

      Result:
      For the entire lobectomy cohort, 3-year OS, DFS, and LCR were 87.9%, 84.9%, and 96.4% respectively. For the entire SBRT cohort, 3-year OS, RFS and LCR were 84.4%, 60.7% and 93.4%, respectively. A total of 246 patients underwent surgery, and 117 received SBRT. There were statistically difference between surgical patient and SBRT patients in tumor histology(P<0.000). Surgical patients had tendency that have longer tumor size than SBRT patients (2.4±1.0 vs. 2.1±0.8, P=0.092). There were no statistically difference between lobectomy and SBRT group with age (68.9±6.6 vs.69.0±9.2, P=0.980), Eastern Coorperative Oncology Group performance scores, Charlson comorbidity Index, pulmonary function test result (FEV1 and predict FEV1), gender, T stage, and tumor location. A propensity matched comparison in a blinded manner (1:1 ratio, caliper distance=0.0025) based on age, gender, WHO performance status score, pulmonary function (forced expiratory volume in 1 second [FEV1] % and FEV1), and T stage resulted in 49 matched pairs. The follow-up period ranged from 0.3 to 60.0 months, with a median of 21.4 months. There were no differences between lobectomy and SBRT in LCR, respectively 97.1% and 100% (p=0.355) at 4 year. Also the 4-year RFS was comparable between groups, as 68.6% after lobectomy, versus 81.9% at 4 year after SBRT (p=0.963). The 4-year OS was similar in both groups, with 58.1% vs. 75.2% for lobectomy and SBRT (p=0.774). No patient experienced treatment-related death in both groups.

      Conclusion:
      This retrospective analysis found no significant difference in LCR, RFS and OS between lobectomy and SBRT. This study indicated matching these disparate cohorts of patients remains challenging. Participation in clinical trials is essential to define the indications and relative efficacy of lobectomy and SBRT in a high-risk population.

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    P3.14 - Radiotherapy (ID 730)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: Radiotherapy
    • Presentations: 1
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      P3.14-004 - Pathological Study on the Clinical Target Volume (CTV) in Limited-Stage SCLC for CT-Simulation Based Thoracic Radiotherapy Planning (ID 9722)

      09:30 - 16:00  |  Author(s): W. Mao

      • Abstract

      Background:
      The microscopic extension, known as clinical target volume (CTV), of the primary tumor in locally advanced non-small cell lung cancer for chest radiotherapy planning has been well studied. However, the CTV of the primary tumor in limited-stage small cell lung cancer (SCLC) for thoracic radiotherapy planning has not been reported. In this study, we tried to quantify CTV of primary tumor in limited-stage SCLC with pathological approach.

      Method:
      Patients with stage T1-2N0-1M0 small cell lung cancer, treated with two cycles of etoposide plus cisplatin neoadjuvant chemotherapy or without neoadjuvant therapy were eligible for this study. Routine radical lobectomy and mediastinal lymph node dissection were performed for these patients. After operation, the intact lung lobe specimens were perfused with 10% neutral formalin and inflated as the natural state in the body. Specimens should be fixed for at least 12 hours. The fixed specimens were sectioned at 3mm thickness along the cross-sectional position of the body, and for each slice, the gross tumor and its surrounding 2cm lung tissue was embedded with paraffin and sliced with 4μm thickness. HE routine staining and CD56 immunohistochemical staining were applied. The slides were scanned by KFBIO reading software, and the pathologists confirmed the microscopic extension of the surrounding tumor. The minimal distances between microscopic nidus and the edge of gross tumor were measured.

      Result:
      Eight patients were enrolled, of whom 4 received 2 cycles of neoadjuvant chemotherapy and 4 received surgery without any neoadjuvant therapy. In patients who received neoadjuvant chemotherapy, one was diagnosed as squamous cell carcinoma after surgery and was excluded for further evaluation of CTV, while 1 patient achieved pathologically complete remission of tumor.The median range of CTV in patients received or did not receive neoadjuvant chemotherapy were 0.4mm (0.05mm-2.76mm) and 1.7mm (0.08mm-12.7mm) respectively, a margin of 1.4mm and 10.2mm could cover 95% of microscopic nidus (P=0.00).

      Conclusion:
      The preliminary results of this study indicated that to take into account 95% of the microscopic nidus, a 1.4mm and a 10.2mm margin should be need for CT-simulation based thoracic radiotherapy planning for limited-stage SCLC patients who were treated with or without induction chemotherapy. However, the sample size of this study was small and more cases are needed to justify the results.