A secondary analysis of FDG spatio-temporal consistency in the randomized phase II PET-boost trial in stage II-III NSCLC

Matthew La Fontaine, Wouter Vogel, Judi van Diessen, Wouter van Elmpt, Bart Reymen, Gitte Persson, Gunnar Westman, Dirk De Ruysscher, Jose Belderbos, Jan-Jakob Sonke*

*Corresponding author for this work

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Abstract

Purpose: FDG-PET scans have shown spatial consistency in NSCLC patients before and following chemoradiotherapy, implying radioresistance. We hypothesized that patients, who received FDG-PET redistributed dose painting, would demonstrate reduced spatial consistency when compared to registered patients or to escalated dose treatment. Methods: Stage II-IIIB, inoperable NSCLC patients were randomized in a phase II trial (NCT01024829) to (chemo) radiotherapy of either homogeneous boosting to the primary tumor, or redistributed inhomogeneous boosting to the GTV subvolume (FDG-SUV > 50% SUVmax). Patients who could not be boosted (>= 72 Gy) received 66 Gy in 24 fractions. Spatial consistency of pre-treatment and post-treatment (3 months) FDG-PET scans was measured by various overlap fraction thresholds. Results: 66/82 patients analyzed received randomized treatment in the trial. Thresholds of 50% SUVmax pre-treatment and 70% SUVmax post-treatment yielded a median overlap fraction of 0.63 [interquartile range: 0.15-0.93], with similar results for other thresholds. No significant differences were found among overlap fractions of the treatment groups. A high incidence of FDG-uptake in normal lung (grade-1 pneumonitis: 73%) was found post-treatment. Conclusion: FDG redistributed boosting did not reduce FDG spatial consistency from pre-treatment to post-treatment, which was highly variable among patients. The study found high numbers of patients with lung inflammation after treatment. (C) 2018 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)259-266
Number of pages8
JournalRadiotherapy and Oncology
Volume127
Issue number2
DOIs
Publication statusPublished - 1 May 2018

Keywords

  • FDG PET
  • Dose painting
  • NSCLC
  • Dose escalation
  • Integrated boost
  • CELL LUNG-CANCER
  • POSITRON-EMISSION-TOMOGRAPHY
  • STEREOTACTIC BODY RADIOTHERAPY
  • DOSE-ESCALATION TRIAL
  • CONFORMAL RADIOTHERAPY
  • THORACIC RADIOTHERAPY
  • RADIATION PNEUMONITIS
  • REGIONAL FAILURE
  • CT SCAN
  • CONCURRENT

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