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
  • Moderators:
  • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall

  • 30681

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    P2.01-72 - Safety of Palliative Radiotherapy and Immune Checkpoint Inhibitors in Patients with Metastatic Non-Small Cell Lung Cancer (ID 2638)

    10:15 - 18:15  |  Author(s): Susanna Y Cheng
    • Abstract
    • Slides

    Background
    

    Immune checkpoint inhibitors (ICIs) are now widely used as standard of care treatments for metastatic non-small cell lung cancer (m-NSCLC) alongside palliative radiotherapy (RT). Commonly used ICIs have long half-lives, typically between 3-4 weeks, and with reported effect even months after discontinuation. The safety of RT based on timing and biologically effective dose (BED) with respect to ICIs is not yet elucidated. This study hypothesized that RT use within 3 months interval prior and after ICI does not increase grade ≥2 toxicities from either ICIs or RT.

    Method
    

    This retrospective analysis includes m-NSCLC patients treated with both RT and ICIs at the Sunnybrook Odette Cancer Centre, Toronto from June 2014 to January 2019. Patients were identified by both our chemotherapy computerized physician order entry system, OPIS and radiation database. ICIs and RT-related toxicities after first ICIs dose were graded as per CTCAE v4.0. Based on timing and location, toxicities attributed to either ICIs or RT by clinicians.

    Result
    

    Forty-four m-NSCLC patients treated with ICIs (nivolumab, pembrolizumab, or atezolizumab) and RT were identified. Twenty one (47.7%) were females, median age 67.5 (33.4- 83.2) years, 36 (81.8%) Caucasian, 42 (95.5%) non-squamous histology, 34 (77.3%) previous or current smokers, PD-L1 1-49% in 7 (15.9%) patients and ≥50% in 15 (34.1%), 9 (20.5%) EGFR/ALK positive, 40 (90.9%) ECOG 0-1. Median follow-up was 10.6 (0.7- 54.6) months. Twenty-five patients (group 1) received RT within 3 months prior and after ICIs (60 courses total, 32 (53.3%) extracranial), with median biologically effective dose with α/β= 10 (BED₁₀) 59.5 (14.4-72.0) Gy₁₀, while 19 had no RT in that interval (group 2). Overall, group 1 had 142 RTs (82 outside interval), with median BED₁₀ 52.7 (14.4-120) Gy₁₀, while group 2 had 51 RTs, with median BED₁₀ 52.8 (10.1-105.6) Gy_10. Grade ≥2 toxicities (8 total, 7 ICIs-related, 1 RT-related) occurred in 7 (28.0%) patients from group 1, and in 4 patients (26.3%) in group 2 (6 total all ICIs-related); this was not statistically significant (χ² p= 0.60). Five grade 3 toxicities were: pneumonitis (2), hepatitis (1), colitis (1), and nausea (1). No grade 4 or 5 toxicity was reported.

    Conclusion
    

    Palliative RT within 3 months of ICIs did not increase ICIs and RT-induced grade ≥2 toxicities. Proceeding with ICIs while receiving palliative RT for m-NSCLC is likely safe. Further research incorporating larger cohort is planned to verify these safety results.

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