Author of

• 20193

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  P3.14 - Radiotherapy (ID 730)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Radiotherapy
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 24199

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    P3.14-009 - Thoracic Re-Irradiation of Lung Cancer Using Highly Conformal Radiotherapy Is Effective as Salvage Treatment Option  (ID 9994)

    09:30 - 09:30  |  Presenting Author(s): Yeon Sil Kim
    • Abstract

    Background:
    Despite wide adoption of intensity-modulated radiation therapy (IMRT), thoracic re-irradiation of lung cancer has been challenged by the tolerance doses of normal tissues such as lung and esophagus. We retrospectively analyzed the local control rate and the toxicity of thoracic re-irradiation using highly conformal radiotherapy.
    
    Method:
    Between September 2008 and November 2015, 50 patients received thoracic re-irradiation with 3D conformal therapy (n=6, 12%), linac-based IMRT (n=11, 22%), helical tomotherapy (n=31, 62%), and stereotactic body radiotherapy (n=2, 4%). Total lung mean dose (~Total~D~mean~) was calculated by the sum of lung D mean of initial radiotherapy (RT) and that of re-RT.
    
    Result:
    Twenty-two patients had distant metastasis at the time of re-RT. Median follow-up time was 14.0 months (range; 1.4 - 65 months) from re-RT. At the time of analysis, local progression after re-RT was observed in 40% (n=20) of patients. The 1-year and 2-year local progression-free survival (LPFS) were 60.3% and 47.1%, respectively. Median time to local progression was 8.5 months (range; 1.4 - 65 months) and median survival from re-RT was 13.9 months (range; 1.4 - 65 months). Median total dose was 70.3Gy (range; 33 - 131 Gy) with median fraction size of 2Gy (range; 1 - 10.9 Gy). Local control rate of 3D-conformal RT and that of IMRT was 50% and 61.4%, respectively. When we compared the LPFS of patients who received re-RT using IMRT, smaller PTV volume was associated with greater LPFS with marginal significance: the 1-year LRFR of PTV<57.5 cm[3 ]and PTV≥57.5cm[3]were 74.5% and 51.7%, respectively (p=0.054). Acute grade 1 and 2 radiation pneumonitis were observed in 16% (n=8) and 10% (n=5), respectively. No acute grade 3 or higher radiation pneumonitis occurred. ~Total~D~mean~of patients with and without acute radiation pneumonitis showed significant difference: 14.8Gy with acute radiation pneumonitis and 12.0Gy without acute radiation pneumonitis (p=0.048). Acute grade 2 esophagitis was observed in 6 patients (12%), and no grade 3 or higher esophagitis occurred. Chronic grade 2 radiation pneumonitis occured in 5 patients, and no chronic grade 3 or higher complications was observed
    
    Conclusion:
    The stratification of patients receiving thoracic re-RT is crucial in extending the indications and improving the efficacy of IMRT. Based on appropriate stratification, thoracic re-RT of lung cancer can be safely delivered using highly conformal radiotherapy with excellent local control and acceptable toxicity.