EPEN-13. PATTERN OF RELAPSE IN POSTERIOR FOSSA EPENDYMOMA GROUP A
Bibliographic record
Abstract
Abstract PURPOSE/OBJECTIVE Posterior fossa ependymoma group A (PF-EPN-A) is a poor prognostic ependymoma subgroup, predominantly seen in infants and young children. Among all ependymomas, most of the recurrences are seen in patients with the PF-EPN-A subgroup. Despite advances in neurosurgery and postoperative adjuvant therapy, management of these tumors remains challenging, and recurrence occurs in over 50% of cases. In this study, we aimed to evaluate the pattern of relapse in PF-EPN-A. MATERIALS AND METHODS The clinical features, treatment strategies and relapse patterns of patients diagnosed and treated with PF-EPN-A at the Hospital for Sick Children, Toronto have been evaluated retrospectively. RESULTS Seventy-five patients were diagnosed with PF-EPN-A at the Hospital for Sick Children, Toronto from 01 June 1996 to 01 June 2022. All patients were treated with surgery +/- focal radiation +/- chemotherapy after diagnosis. Out of 75 patients, 38 (50.6%) had recurrent disease. Twenty-three patients (60.5%) had a local relapse while 15 patients (40.5) experienced a distant relapse. Out of 23 patients who had a local relapse, only 8 patients (34%) developed a local relapse after a gross total resection (GTR). Other 15 patients developed a local relapse after either subtotal (STR) or near total resection (nTR). Out of 15 patients who experienced a distant relapse, 10 patients (66%) developed a distant relapse after GTR. Time to relapse was mean 32 months (11-132 months) after GTR and 24 months (1-98 months) after STR /nTR. CONCLUSIONS The modern management approach (more aggressive resection and early conformal radiotherapy) changed the relapse pattern and the classical dogma that “nearly all relapses in ependymoma are local’’ in modern series. This study supported the importance of GTR in the management of PF-EPN-A and also demonstrated that PF-EPN-A tends to recur more on distant sites rather than locally when the initial surgical intervention is a GTR.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".