Management of complicated tumor response (CTR) to tyrosine kinase inhibitors (TKI) in gastrointestinal stromal tumor (GIST) patients (pts) with locally advanced/metastatic disease
e21512 Background: Bleeding, perforation, and infection may complicate TKI therapy in GIST. Their incidence and best management are not completely known yet. Methods: Between May 2001 and December 2008, 278 pts were treated with imatinib or sunitinib, respectively, as first or second line therapy. Pts experienced bleeding, perforation and colliquation with superimposed infection were recorded and reviewed. Results: CTR occurred in 24 pts (9%) after a median time of 241 days from treatment start (8–2090 days). In 5 pts the complication took place after increasing the dose. Before complication, according to RECIST criteria, a partial response (PR) and a stable response (SD) were respectively documented in 16 and 8 pts . Radiologically assessed bleeding in closed lesions was seen in 13 pts (5%). All but one were treated conservatively with supportive care and blood transfusions. The other pt required surgical resection of his peritoneal bleeding lesion. Nine pts (3%) developed colliquation with bacterical superinfection: 5 were treated with antibiotics, 4 had their lesions drained. Two pts underwent emergency surgery due to perforation with a superimposed infection. In 21 out of 24 pts the event resolved without sequelae. Three pts died: 2 developed massive haemorrhage, 1 had a bowel perforation. After stopping treatment for a median interval of 10 days (2–63), all but one restarted treatment at the previous dose. No further complications were seen after the first event. Eight pts are still on treatment with a SD, 2 pts switched to a second line therapy due to progressive disease (PD), 11 died due to PD. Conclusions: Bleeding, perforation and colliquation with superimposed infection may occur at different time intervals from treatment start. Even if supportive care and medical therapy are successful in most of cases, pts should be carefully monitored because these complications can be life-threatening. Surgery should be considered in case of failure of conservative treatment. Reintroduction of the therapy at the same dose is feasible and well tolerated. [Table: see text]