e20506 Background: The aim of this work was to investigate factors predicting progression-free survival (PFS) and overall survival (OS) of patients (pts) with advanced GIST treated with 400 mg/day IM included in the BFR14 study.
METHODS
434 pts were included in this prospective multicenter trial from June 2002 to July 2009. After 1, 3 and 5 yrs of IM 400mg/day, pts free from progression were randomly offered to continue or interrupt (I arm) IM. Pts allocated to the I arm could restart IM (same dose) in case of progression. Pts declining randomization proceed with IM. Since time to secondary resistance to IM and OS were similar in both arms, prognostic factors for survival were therefore investigated in the entire cohort (randomized and not randomized pts) included in the BFR14. Survival was defined from the date of inclusion to the date of death for OS or to the first occurrence of progression or death for PFS. Baseline characteristics were tested in a univariate step. Variables statistically significant at 0.10 alpha-level were included in a multivariate Cox model. A backward stepwise procedure was used to identify independent prognostic factors for PFS then OS.
RESULTS
As of January 2011, after a median follow-up of 41.7 months (CI95% = [35.2 - 48.4]), there were 254 events (58.5%) and 134 deaths (30.9%). The 2 and 3-yrs PFS were 52% and 42% respectively. PS 0, normal platelets count and CD34-positivity on tumor cells were the three independent prognostic factors of a higher PFS. The 2 and 3-yrs OS were 83% and 73% respectively. A higher OS was independently predicted by sex (female), PS (0), platelets count (<400 giga/L) and lymphocytes count (>1,500/mm3). Mutational analysis is ongoing.
CONCLUSIONS
In this large series of advanced GIST pts treated with standard dose IM, pts with a good PS and normal platelet counts have a favourable outcome, both on PFS and OS. GIST expressing CD34 have a better PFS. Male GIST pts and pts with lymphopenia have a dismal OS.