Data Management and Statistical Analysis
Data were collected prospectively and entered by the local center’s data
manager into the database POND (Pediatric Oncology Network
Database)11 (this database was retired in 2019). Data
frozen as of December 31st 2017 are included in this
report. The data were reviewed and confirmed by the primary country team
and the PI, with constant quality reviews. Abandonment of therapy was
defined as failure to return to continue treatment for 4 weeks or
more12. Lost to follow-up was defined as 2 years from
the end of therapy. Upfront refusals were excluded from the analysis.
Primary outcomes were abandonment-sensitive event-free survival (AS-EFS)
and abandonment-sensitive overall survival (AS-OS)13.
AS-EFS was defined as the time from date of diagnosis to date of first
event (progressive disease, relapse, abandonment, or toxic death) or
date of last contact for those who were event-free. AS-OS was calculated
as time from diagnosis to abandonment or death, or last contact for
those still alive. In addition, EFS and OS rates censoring abandonment,
were also calculated. Survival rates were estimated using the
Kaplan-Meier method with standard errors of Peto et
al14,15 The two-sided log-rank test was used for
comparison of survival curves. P-values <0.05 were considered
statistically significant for all comparisons. All analyses were
performed using SAS® version 9.4. Graphics were generated using R
(http://www.R-project.org, version 4.1.1).