Predictive significance of pretreatment 18F-FDG PET volumetric parameters on survival outcomes in pediatric patients with locally advanced undifferentiated nasopharyngeal carcinoma.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a rare pediatric cancer. Most children are first diagnosed with advanced locoregional disease. Identification of patients at higher risk of treatment failure is crucial as they may benefit from more aggressive initial treatment approaches. 18Fluorine-labeled fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET) has shown promise as a prognostic tool for predicting outcomes. METHODS: Retrospective study of pediatric patients with locally advanced undifferentiated NPC who underwent 18F-FDG PET/CT prior to intial treatment. Predictive significance of metabolic PET parameters on survival outcomes were estimated. RESULTS: Thirty-two children were included, age range was 7.1-18 years at the time of diagnosis. The median follow-up duration was 46.1 months. Three patients (9.4%) were classified as AJCC stage IIb, 13 patients (40.6%) as stage IIIa, eight patients (25%) as stage IIIb, and eight patients (25%) as stage IVa. Our findings revealed that high whole-body metabolic tumor volume at the threshold of hepatic reference SUVmean (WB-MTV-HR) (>135 mL) was associated with significantly lower event-free survival (EFS) compared to the low WB-MTV-HR group (≤135 mL) (3-year EFS: 50% ± 18% vs. 82% ± 8%; p = .015). Additionally, the 3-year overall survival (OS) rates differed significantly between the high whole-body metabolic tumor volume at the threshold of an SUV of 2.5 isocontour (WB-MTV-2.5) group (MTV >74 mL) and the low WB-MTV-2.5 group (MTV ≤74 mL) (63% ± 18% vs. 100%; p = .021). CONCLUSION: Our study suggests that WB-MTV parameters could serve as significant prognostic factors for disease progression in pediatric patients with locally advanced undifferentiated NPC. However, further prospective studies with larger sample sizes are needed to validate these findings.

Different 18 F-FDG PET parameters for the prediction of histological response to neoadjuvant chemotherapy in pediatric Ewing sarcoma family of tumors.

BACKGROUND: The histological response to neoadjuvant chemotherapy (NAC) in pediatric patients with Ewing sarcoma family of tumors (ESFT) can predict the disease-free survival. Therefore, a noninvasive method for response assessment is needed. Using the currently established imaging modalities, mass reduction does not always correlate with the percentage of necrosis. OBJECTIVE: To determine the potential role of 18 fluorine-labeled fluoro-2-deoxyglucose positron emission tomography (18 F-FDG PET) metabolic parameters in the prediction of poor histological response to NAC in pediatric patients with ESFT. METHODS: Thirty-six patients who were treated with NAC and surgery at the Children's Cancer Hospital, Egypt, were prospectively included in this study. All patients underwent two studies; a PET/CT study before NAC and another one after NAC completion. Metabolic PET parameters were measured in each study. The ability of each of these parameters, their pretreatment and pre-local control values, as well as the percentage reduction between their pretreatment and pre-local control values, were evaluated to differentiate between good and poor responders using the histological response as a standard reference. RESULTS: Neither the pretreatment value nor the percentage reduction of any of the measured PET parameters predicted poor histological response. After NACcompletion, metabolic tumor volume (MTV) at the threshold of an SUV of 2.5 isocontour (MTV(2.5)post ), MTV at the threshold of hepatic reference SUVmean (MTV(HR)post ), and total lesion glycolysis at the threshold of hepatic reference SUVmean (TLG(HR)post ) predicted poor histological response (P  = 0.006, 0.018, and 0.003, respectively). The cutoff values of 90% reduction of TLG(HR) and maximum standardized uptake value (SUVmax)post ≤2.5 could differentiate between good and poor responders. CONCLUSION: FDG PET parameters can predict poor histological response to NAC in ESFT patients. MTV and TLG at the thresholds of an SUV of 2.5 isocontour and hepatic reference SUVmean are the two most promising thresholds in predicting the response of patients. The cutoff value of SUVmaxpost ≤2.5 predicts poor histological response.

Outcome predictors of autologous hematopoietic stem cell transplantation in children with relapsed and refractory Hodgkin lymphoma: Single-center experience in a lower-middle-income country.

BACKGROUND: Children and adolescents with HL have excellent long-term survival exceeding 95% after combined modality treatment. However, about 20% will either relapse or have PRF. Salvage HDCT followed by AHSCT is considered to be the preferential treatment. OBJECTIVE: To describe the outcome (OS and EFS) and prognostic factors in pediatric patients with relapsed or refractory HL (r/rHL) who underwent AHSCT. METHODS: We retrospectively included 43 pediatric patients with r/rHL who underwent AHSCT from July 1, 2007, till December 31, 2016, at the Children's Cancer Hospital of Egypt. MAC regimen given was CMV. RESULTS: Of the whole cohort, 88.4% of patients achieved CR, while 11.6% had a positive PET scan prior to transplantation. The 3-year OS and EFS were 85% and 70.6%, respectively. The 3-year OS for patients > 10 years was 94% versus 65.5% for patients 10 years of age or younger (P = 0.046). There is strong tendency toward better 3-year OS for patients with negative PET scan as compared to those with positive PET scan before AHSCT, 89.4% vs 60%, respectively (P = 0.059). This tendency is also applicable when looking at the 3-year EFS for the two groups, 78.3% vs 40%, respectively (P = 0.069). CONCLUSION: Poor predictors of OS were younger age and positive PET scan before AHSCT. The latter, along with single modality treatment before AHSCT, were poor predictors of EFS.