A process involving periodic contact with patients enrolled in a clinical trial for the purpose of administering the assigned treatment(s), observing the effects of treatment(s), modifying the course of treatment(s), or for collecting required data.
Based on the results of this analysis on a large prospective series, we retrospectively evaluated the prognostic impact of the t(12; 21) translocation in the closed German ALL-BFM 90 and Italian ALL-AIEOP 91 protocols that have sufficient follow-up for the analysis.