Abstract
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Objectives The International Pediatric Non-Hodgkin Lymphoma Response Criteria recommends 18F-FDG PET/CT to evaluate response after completion of chemotherapy but questions utility after interim chemotherapy.[1] This study investigates the prognostic value of interim chemotherapy 18F-FDG PET/CT qualitative therapy assessment, as per the Lugano Classification, in pediatric patients with Non-Hodgkin Lymphoma (NHL).
Methods 29 pediatric patients, aged 2 - 17 years, with NHL had a total of 40 18F-FDG PET/CT scans performed at interim time points status post variable cycles of chemotherapy (range, 1-5 cycles; mean 2.8±0.9 cycles). PET/CT scans were evaluated using the Lugano Classification 5 point scale (5PS): 1, no uptake above background; 2, uptake ≤ mediastinum; 3, uptake > mediastinum but ≤ liver; 4, uptake moderately < liver; 5, uptake markedly higher than liver and/or new lesions. The 5PS was dichotomized to negative (score 1, 2, and 3) or positive (score 4 and 5) results based on the Lugano Classification for complete response versus partial response, no response and progressive disease, respectively. Kaplan-Meier Survival Curves and Cox-regression analysis were performed.
Results The 29 pediatric patients had a total of 11 different subtypes of NHL: Burkitt lymphoma (40%), T-cell lymphoma (15%), Diffuse large B-cell lymphoma (12.5%), Subcutaneous panniculitis-like T-cell lymphoma (7.5%), Mature B-cell lymphoma (2.5%), Undifferentiated mature B-cell lymphoma (2.5%), Marginal Zone Lymphoma (5%), Anaplastic large cell lymphoma (5%), Myeloid leukemia (2.5%), NK Cell cutaneous lymphoma (2.5%), Pre B-cell lymphoblastic leukemia (5%). Of the 40 interim chemotherapy 18F-FDG PET/CT scans performed on these 29 patients, 15 were positive (score 1, 2, and 3) and 24 were negative (score 4 and 5) based on the Lugano Classification 5PS. Total overall survival (OS) ranged from 1.2 - 97.2 months. Median OS ± standard deviation was 38.6 ± 27.4 months for the positive group and 50.2 ± 25.3 months for the negative group. Kaplan-Meier Survival Curves demonstrated statistically significant (p=0.04) separation in OS curves.
Conclusions 18F-FDG PET/CT qualitative therapy assessment based on the Lugano Classification at interim time points during chemotherapy can predict overall survival in pediatric patients with NHL.