Outcomes of Pediatric Patients with metastatic Ewing sarcoma treated
with interval compression
Abstract
Background: Interval compression (IC), defined as 2 week-long cycles of
alternating vincristine/doxorubicin/cyclophosphamide and
ifosfamide/etoposide, improves survival for localized Ewing sarcoma. The
outcomes of patients with metastatic disease treated with IC are
uncertain. Methods: We retrospectively reviewed the charts of pediatric
patients with metastatic Ewing sarcoma treated with IC at our center
between January-2013 and March-2020. We calculated event-free survival
and overall survival and used log rank tests for univariate comparisons.
Results: We identified 34 patients aged 2.7–17.1 years (median,11.6
years). Twenty-six patients (76%) had pulmonary metastases, and 14
(41%) had extra-pulmonary metastases in the bone (n = 11), lymph nodes
(n = 2), and intraspinal tissue (n = 1). All patients received local
control therapy: surgery only (n = 7, 21%), radiotherapy only (n = 18,
53%), or both (n = 9, 26%). The estimated 3-year OS and EFS were
62%±9% and 39%±9%, respectively. Patients with pulmonary only
metastasis had a 3-year OS of 88%±8% in comparison to those with
extra-pulmonary metastasis of 27%±13% (P=0.0074). Survival did not
differ according to age group (> vs < 12 years),
metastasis site, or primary tumor site, but 3-year event-free survival
significantly differed according to local control therapy (surgery only,
83% ± 15%; combined surgery and radiation, 30% ± 18%; radiation
only, 15% ± 10%; P = .048). Conclusion: IC yielded similar outcomes
for patients with metastatic Ewing sarcoma to that reported in the
literature using other regimens. We suggest including this approach to
other blocks of therapy