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Elena Wilson



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    OA 01 - The New Aspect of Radiation Therapy (ID 652)

    • Event: WCLC 2017
    • Type: Oral
    • Track: Radiotherapy
    • Presentations: 1
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      OA 01.05 - Analysis of Radiotherapy Quality Assurance Data for the Convert Trial - Does Non-Compliance to Protocol Affect Survival? (ID 10117)

      11:45 - 11:55  |  Presenting Author(s): Elena Wilson

      • Abstract
      • Presentation
      • Slides

      Background:
      The CONVERT Trial is a multicentre phase III study which recruited 547 patients with limited-stage SCLC from April 2008 to November 2013. Patients were randomised to receive once daily (66Gy in 33 fractions) or twice daily (45Gy in 30 fractions) radiotherapy concurrently with chemotherapy. The primary endpoint was overall survival. This study investigates the effect of non-compliance to radiotherapy protocol on survival for the CONVERT Trial.

      Method:
      489/557 received chemo-radiotherapy according to protocol. As part of the CONVERT trial quality assurance (QA) programme, 94 patient datasets (19.2%) treated with concurrent chemoradiotherapy (n=489) were reviewed and deviations from protocol were categorised as acceptable, acceptable variation and unacceptable variation using the Global Harmonisation Group (GHG) variation definitions. Organ at risk outlining (heart, spinal canal and lung minus planning target volume (PTV)), target delineation and margins applied, PTV coverage, treatment planning technique and radiotherapy treatment time were reviewed and classified according to the GHG definitions. A multiplicative factor (F) was calculated for each treatment plan, based on the GHG definitions. A low factor indicates a low number of protocol deviations. Protocol deviations were correlated with survival and number of patients recruited per centre.

      Result:
      94/489 patients were included in this analysis (19.2% of the randomised patients). The median number of patients recruited per centre was 6 (range 1-109). Protocol deviations were categorised as acceptable (57.6%), acceptable variation (23.3%) or unacceptable variation (19.1%). Amongst the unacceptable variations the PTV coverage was the most common deviation to protocol. In these 71 patients (75.5%) the dose distribution within the PTV was greater than 7% of the prescribed dose. Patients with increasing number of organ at risk outlining protocol deviations and with an increase in the multiplicative factor (F) had a lower survival. Further details will be presented at the meeting including survival in the 3 GHG categories. Centres recruiting >25 patients were found to have a lower number of protocol deviations (median 2, range 2-3) compared with centres recruiting fewer than 25 patients (median 3, range 0-4.5), and were most likely to delineate organs at risk correctly.

      Conclusion:
      High recruiting centres are most likely to comply with a trial protocol. Overall survival was affected by the number and type of protocol deviations, highlighting the importance of a robust trial QA programme in prospective radiotherapy trials.

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