I have been diagnosed with a GIST 6x5x4 cm right at the end of my tail. I have been told because of its location and size, it is too large to operate on now. They have prescribed Imatinib with the hopes that in 6 months there MIGHT be enough shrinkage to allow an operation but that I might be on Imatinib for as long as 6 years to hopefully prevent a reoccurrence. I have read the potential side effects of Imatinib and they are to say the least "frightening". My question, have others had Imatinib, and if so would they be kind enough to share their experience. THANKS!