Prognostic time dependence of deletions affecting codons 557 and/or 558 of KIT gene for relapse-free survival (RFS) in localized GIST: a Spanish Group for Sarcoma Research (GEIS) Study.

Background: To assess whether deletions involving codons 557 and/or 558 (critical deletions) of exon 11 of KIT are relevant in the prognosis of relapse-free survival (RFS) in gastrointestinal stromal tumor (GIST) patients with a long follow-up.

Patients And Methods: A univariate and multivariate analysis for RFS were carried out on 162 localized GIST patients over the entire follow-up period and over the intervals 0-4 years and >4 years. Factors assessed among others were Fletcher/National Institutes of Health and Miettinen-Lasota/Armed Forces Institute of Pathology (M-L/AFIP) risk categories, critical deletions and non-deletion-type mutation (NDTM) within exon 11 of KIT.