Author of

• 30601

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  P2.01 - Advanced NSCLC (ID 159)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Advanced NSCLC
  • Presentations: 1
  • Now Available
  • Moderators:
  • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall

  • 30700

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    P2.01-89 - Feasibility of Individualized Multidisciplinary Treatment for Locally Advanced Non-Small Cell Lung Cancer Based on the Treatment Planning (Now Available) (ID 2032)

    10:15 - 18:15  |  Presenting Author(s): Yu Liu
    • Abstract
    • Slides

    Background
    

    In the individualized multidisciplinary treatment of patients with locally advanced non-small cell lung cancer (LANSCLC), the feasibility of dose escalation to the patients with sequential chemoradiotherapy for increasing tumor control and dose reduction to the patients with concurrent chemoradiotherapy for mitigating the side effects of radiotherapy was analyzed in the aspect of treatment plan optimization.

    Method
    

    Fifty patients with LANSCLC were randomly chosen from Shanghai Pulmonary Hospital and treatment plans were replanned. These patients’ PTV was defined as CTV+0.4cm, and CTV was the extravasation of 0.6-0.8cm of GTV, at least 95% volume of the PTV receive 60Gy/30fx, and these plans were called control group. The initial GTV was taken as GTV1, and GTV2 was obtained after GTV irradiated 40Gy; PTV1 was defined as GTV1+0.4cm, and PTV2 was defined as GTV2+0.4cm. With PTV2 dose escalated, the plans with lung remaining the same dose as control group were the Test1 group, and the plans with PTV1 receiving 60Gy and PTV receiving 45Gy were the Test2 group. The feasibility of the treatment regimen for Test1 Group and Test2 Group was analyzed from the perspective of dose drop gradient and the sparing of OARs, respectively.

    Result
    

    By comparing Test1 group with control group, it is found that the dose PTV2 received is affected greatly by the volume ratio, V_PTV-PTV1/V_PTV, which will escalate when V_PTV-PTV1/V_PTV increases. When V_PTV-PTV1/V_PTV is in these range, 0.2~0.3, 0.3~0.35, 0.35~0.4, 0.4~0.45, then the dose escalated for PTV2 will be 63Gy, 66Gy, 69Gy and 72Gy. And by comparing Test2 group with control group, it is found that the dose received by OARs will be reduced in Test2 group, for example, V5, V20, V30 and MLD for lung will decrease 2.17%±1.2792%, 1.7148%±1.04733%, 1.9982%±1.165%, 1.299Gy±0.564Gy, respectively; V50 and MHD for heart will decrease 1.9128%±2.1184%, 1.229Gy±0.921Gy, respectively; V60, Dmax and MED for esophagus will decrease 5.41%±5.91%, 4.6296Gy±4.4479Gy, 2.3491Gy±1.3411Gy, respectively, and all the p values are far less than 0.05.

    Conclusion
    

    Individualized radiotherapy can be performed on LANSCLC, and V_PTV-PTV1/V_PTV can be used to predict the dose drop gradient. In Test1 group, considering not add additional dose to lung, the larger V_PTV-PTV1/V_PTV, the higher the PTV2 can escalate. In test2 group, reducing the initial irradiation-field dose significantly decreases the dose OARs received, and it is meaningful that more locally advanced patients can receive concurrent chemoradiotherapy. This study will facilitate the individualized multidisciplinary treatment of patients with LANSCLC, which needs further prospective studies to confirm.

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