Author of

• 17783

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  P2.05 - Poster Session with Presenters Present (ID 463)

  • Event: WCLC 2016
  • Type: Poster Presenters Present
  • Track: Radiotherapy
  • Presentations: 1
  • Moderators:
  • Coordinates: 12/06/2016, 14:30 - 15:45, Hall B (Poster Area)

  • 17800

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    P2.05-017 - Tumor Regression Gradient Predicts Disease Free Survival (ID 5926)

    14:30 - 14:30  |  Author(s): L. Paelinck
    • Abstract

    Background:
    Tumor regression during chemoradiation (CRT) in stage III non-small cell lung cancer patients has been described. Our aim was to investigate whether the extent of the primary tumor shrinkage is associated with local control and survival.
    
    Methods:
    Changes in the volume of the primary tumor (GTV-T) of 41 patients treated with concurrent (cCRT) (n = 21) or sequential (sCRT) (n=20) CRT were analyzed using cone-beam CT (CBCT) at every fifth fraction (F5–F30). Only changes in the primary tumor (excluding the lymph nodes) were considered. Previous research revealed F15 and F20 as optimal timing for treatment adaptation for cCRT and sCRT respectively (Berkovic et al. Acta Oncol 2015). Local control and survival data were reviewed retrospectively. Impact of the tumor regression at the time of the optimal adaptation timing during treatment (higher or lower than median) and chemotherapy schedule (cCRT vs. sCRT) on local control and survival were evaluated using the Kaplan-Meier survival comparison (log-rank test, p<0.05 were considered significant).
    
    Results:
    Median local control (LC) and overall survival (OS) was 32.5 res. 29.9 months in the sCRT and 31.4 res. 23.3 months in the cCRT group. LC and OS did not differ significantly for the cCRT and sCRT cohort. The median GTV reduction was 35.0% (range 2.8–64.2%) at F15 for cCRT, while 21.9% (2.1-53.5%) at F20 for sCRT patients. Higher than the group median (for cCRT and sCRT) GTV-T reduction showed statistically significant impact only on disease specific survival (p=0.016, Figure 1).
    
    Conclusion:
    Higher gradient GTV-T reduction during RT significantly correlates with better disease specific survival. Additional tumor and patient characteristics should be studied in larger patient cohorts to further understand tumor behavior and to offer a validated predictive tool of therapeutic outcomes. Figure 1. Kaplan-Meier survival curve for DSS. Figure 1