Explored prognostic factors for survival in patients with advanced GIST treated with standard dose imatinib (IM): Results from the BFR14 phase III trial of the French Sarcoma Group

10092 Background: Factors predicting progression free survival (PFS) and overall survival (OS) of patients (pts) with advanced GIST treated with 400 mg daily dose IM included in the BFR14 study with a median follow up of 54 months (CI95%:47-61) was investigated evaluating added prognostic factors. 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. Prognostic factors for overall survival were 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 disease progression under imatinib or death for PFS. A multivariate cox model including statistical significant baseline characteristics tested in univariate were included in a backward procedure d to identify independent prognostic factors for PFS then OS. Results: As of January 2012, there were 285 progressions (65%) and 161 deaths (37%). The median PFS of the entire cohort was 29 months (CI95%: 24-33) and the 4 and 5-yrs PFS were 31% and 24% respectively. A low tumour volume at inclusion, PS (0), sex (female), CD34 positivity on tumor cells were the four independent prognostic factors of a higher PFS. The 5-yrs OS was 54% (CI95%: 48-60). A higher OS was independently predicted by gender (female), PS (0), platelets count (