Interim 18F FDG-PET as a probable predictor of mortality in pediatric PTLD Conferences uri icon

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abstract

  • Objectives: A retrospective, single center study was undertaken to evaluate the predictive role of ‘interim’18F-FDG positron emission tomography (PET) performed during treatment in pediatric patients confirmed to have post-transplant lymphoproliferative disorder (PTLD). Methods: A total of 28 pediatric patients (12 female and 16 males, mean age 10 ± 4.4) diagnosed with PTLD who had PET/CT scans at diagnosis and during treatment (56 scans) were enrolled. Two nuclear medicine physicians and one radiologist independently interpreted the results of PET and CT scans, respectively. We analyzed the effect of the results of interim PET/CT on the mortality risk using both qualitative Deauville five-point scale and semi-quantitative criteria (using 66% cut-off to define rapid versus slow responders). Results: According to the Deauville criteria, 18 patients had positive interim PET (score 4 and 5), and 10 patients had negative results (score 1, 2, and 3). Using semi-quantitative criteria, 19 patients were categorized as slow responders (SR), and 9 as rapid responders (RR). There were 8 deaths (28.5%) over a mean follow up period of 35 ± 32 months. Increased risk of mortality was noted in patients with positive interim PET and slow responders. Five out of eight patients (62.5%) who died had positive interim PET results while six out of eight patients (75%) were slow responders according to the semi-quantitative analysis (p = 0.01 and p = 0.003, respectively). Given the fact that there are other confounders that might lead to risk of mortality of pediatric patients with PTLD, larger cohort is needed. Conclusion: Interim PET scan using either qualitative Deauville five-point scale or semi-quantitative criteria may have a predictive role in pediatric PTLD patients. Further investigation with multicenter studies and larger numbers of subjects are suggested.