Indication and results of surgery following imatinib treatment of locally advanced or metastatic GI stromal tumors (GIST)

9500 Background: Imatinib mesylate efficiently induces tumor remission in advanced GIST however the curve of progression-free survival (PFS) in the large randomised trials does not reach a plateau. Surgery after achieving a PR is often recommended to remove tumor remnants or seems to be the treatment of choice to control tumor progression not or no longer controlled by drugs. The true impact of surgery is unclear and we analysed the indication and outcome of resective procedures including patients treated outside randomised trials. Patients: In a multi-institutional setting, we collected data from 113 patients after surgery for histologically confirmed GIST after imatinib treatment since April 2002. Primary tumor location: esophagus 3, stomach 23, small bowel 46, rectum 21, extraintestinal 20 pts. Indication for resection: to remove remnants of tumor sites responding well to imatinib 44 pts, resection of progressive lesions 55 pts, resection of a primary tumor after intended neadjuvant treatment 14 pts. M...