fractions. All institutions customized their lung blocks however the thickness varied to provide 50 to 70% transmission. 67% specified mid lung dose whereas 37% did not specify lung dose for lateral TBI. Of the 67% who specified mid lung dose, only 33% used CT or 2D imaging to estimate the mid lung dose. No CT planning was done for lateral TBI. 100% of the physician responders answered "yes" to redefining current TBI techniques and > 75% supported the investigation of new TBI techniques in an effort to lower the lung doses. Conclusion: The practice of TBI amongst COG institutions is very heterogeneous. Dose accuracy is difficult to assess as few perform CT-based planning. These findings warrant caution to be exercised when interpreting radiation related efficacies and toxicities when multi-institutional clinical studies are carried out. COG is currently undertaking steps to standardize the practice of TBI.
PURPOSE
Pediatric Spinal cord ependymoma (SCE) is rare, and the management is often heterogeneous across centers. We evaluated the impact of clinical, pathologic, and treatment-related factors on outcomes in a multi-institutional, international cohort.
METHODS
SCE patients age <21 years were reviewed across 5 institutions. We utilized nonparametric descriptive statistics, survival, and recursive partitioning analysis (RPA) to examine patient, tumor, histopathologic and treatment characteristics, failure pattern, and cause of death.
RESULTS
125 patients were identified, 18 (14.4%) with metastases. Initial surgery was GTR, and STR in 44, 56% of patients respectively. Histology was grade 1, 2, and 3 in 55, 17.7 and 23.2% respectively. 55 patients with initial GTR were observed (52.7%) or irradiated (43.6%); 60 patients had STR and were observed (40%) or irradiated (60%). The 7-year event-free (EFS) and overall survival (OS) was 60% (95% CI 51.5–71.4) and 79% (95% CI 71.1–87.8) respectively. STR and metastasis increased the hazard for death [HR 1.87, 95% CI 1.02–3.57, p=0.05 (vs. GTR)] and [HR 2.28, 95% CI 1.1–5.2, p=0.048 (vs. localized)] respectively. Across 43 failures, local failure predominated (48.8%). Distant and combined failure occurred in 30.2 and 13.9% respectively. Adjuvant RT offered a 20% absolute improvement (vs. observation) in EFS at 5 years regardless of extent of resection. RPA identified thoracic (vs. non-thoracic), grade (1 & 3 vs. 2), STR (vs. GTR) and metastases as determinants of inferior EFS.
CONCLUSIONS
Tumor and treatment-related factors are predictive of EFS. OS is favorable despite diverse schema and frequent distant failures.
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