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Takashi Mizowaki



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    P1.16 - Treatment of Early Stage/Localized Disease (Not CME Accredited Session) (ID 948)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall
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      P1.16-25 - A Propensity Score Model for Appropriate Treatment Selection (Sublobar Resection vs. SBRT) In Patients With cStage I NSCLC (ID 11246)

      16:45 - 18:00  |  Author(s): Takashi Mizowaki

      • Abstract
      • Slides

      Background

      Stereotactic body radiotherapy (SBRT) and sublobar resection (SLR) are current treatment options for patients with cStage I non-small-cell lung cancer (NSCLC) who are operable, but at high risk for lobectomy. However, optimal selection of the two treatments remains controversial. Purposes of this study are to identify pre-treatment factors affecting treatment decision and to evaluate their impact on outcomes.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      We retrospectively reviewed patients who underwent SBRT or SLR for cStage I NSCLC because of medical comorbidity between 2003 and 2009. Patients who were with performance status of 2 or worse, those who had no data on pre-treatment pulmonary function test, or those who had no histological confirmation of NSCLC were excluded. A propensity score (PS) model of treatment decision (0 toward SBRT, and 1 toward SLR) was generated using stepwise logistic regression incorporating pre-treatment factors.

      4c3880bb027f159e801041b1021e88e8 Result

      Ninety-two and 65 patients who underwent SBRT and SLR, respectively, were enrolled into this analysis. Median potential follow-up period was 8.6 years. The following factors remained in the PS model after stepwise selection: age, sex, Charlson comorbidity index (CCI), body mass index (BMI), forced expiratory volume in 1 second (FEV1) and tumor diameter. Old age, male, CCI of 1 or more, underweight BMI and large tumor had coefficients toward SBRT (Table).

      In a cohort with PS of 0.5 or more, overall survival was significantly better in SLR patients than in SBRT patients (79.5% and 47.5% at 5 years, respectively; P = 0.004). In a cohort with PS<0.5, whereas, overall survival was similar between SLR and SBRT (43.3% and 39.7% at 5 years, respectively; P = 0.805).

      Coefficients for propensity score
      Factors Coefficients
      (Intercept) (3.95)
      Age per 10y -0.53
      Sex female 0 (ref)
      male -0.62
      CCI 0 0 (ref)
      1 -0.41
      >=2 -0.97
      BMI underweight -0.98
      normal 0 (ref)
      overweight 0.44
      FEV1 per 1L 0.84
      Tumor diameter per 1cm -0.34

      8eea62084ca7e541d918e823422bd82e Conclusion

      The PS model would help appropriate treatment selection for high-risk operable patients. Although patients with PS of 0.5 or more benefit from SLR, SBRT provides comparable outcomes for patients with PS<0.5.

      6f8b794f3246b0c1e1780bb4d4d5dc53

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    P2.01 - Advanced NSCLC (Not CME Accredited Session) (ID 950)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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      P2.01-98 - Single-Isocenter Volumetric-Modulated Arc Radiosurgery for Non-Small-Cell Lung Cancer Patients with Multiple Brain Metastases (ID 12412)

      16:45 - 18:00  |  Author(s): Takashi Mizowaki

      • Abstract
      • Slides

      Background

      Radiosurgery for multiple brain metastases (BMs) in patients with non-small-cell-lung cancer (NSCLC) is a well-established treatment option. However, only 1–4 BMs can be treated by conventional linear-accelerator-based radiosurgery because the treatment time becomes longer as the number of BMs increases. Advanced volumetric modulated arc therapy combined with image-guided radiotherapy enables the realization of single-isocenter volumetric-modulated arc radiosurgery (VMAR), a novel irradiation technique. VMAR irradiates multiple BMs simultaneously using only one isocenter and within a short treatment time. Here we report our initial experience with VMAR.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      The clinical records of 19 patients with 115 BMs from NSCLC were retrospectively analyzed. All patients were treated by VMAR for multiple BMs from October 2015 to September 2017 at our institution and received follow-up magnetic resonance imaging at least once after VMAR. The median patient age was 69 years. The median Karnofsky Performance Scale score was 90; five patients had been previously treated with whole-brain radiotherapy. The histology of the primary tumor was squamous-cell carcinoma in one patient and adenocarcinoma in 18 patients; 12 patients had either an EGFR or ALK alteration. A planning target volume (PTV) was created by expanding the contrast-enhanced lesion with a 1- or 2-mm margin. The median peripheral prescribed dose was 28 Gy, delivered in five fractions. All lesions were set to be covered by ≥99.5 % of the prescribed dose.

      4c3880bb027f159e801041b1021e88e8 Result

      The median follow-up period was 8.5 (range, 1.7–29.9) months. The median number of PTVs was four (range, 2–18). The median PTV was 0.49 (range, 0.13–13.49) cm3, and the median total PTV 8.3 (range, 1.52–18.87) cm3. The median PTV was significantly smaller in patients with than without genetic alterations to their tumor. The probabilities of local control, overall survival, and developing new BMs at 12 months were 100%, 68.4%, and 51.1%, respectively. Acute adverse events included grade 2 alopecia in four patients and seizure in one patient. The number of PTVs in patients with grade 2 alopecia was more than six. Two patients developed grade 2 central nervous system necrosis as a late adverse event. No grade 3 or higher toxicities were noted.

      8eea62084ca7e541d918e823422bd82e Conclusion

      While VMAR achieves good local control, the development of temporary alopecia remains to be addressed. More cases and a longer- follow-up period are required to verify the efficacy of VMAR.

      6f8b794f3246b0c1e1780bb4d4d5dc53

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