Tumor characteristics and treatment (trt) patterns following disease recurrence in gastrointestinal stromal tumor (GIST) patients (pts) who received adjuvant imatinib (IM) as primary trt: A retrospective chart extract-based approach.

Abstract

e21514 Background: Though adjuvant IM trt is associated with a reduced risk of GIST recurrence, little is known about tumor characteristics and trt patterns at the time of recurrence. The study describes tumor characteristics and trt patterns in pts with recurrent disease after completing treatment with adjuvant imatinib for resectable disease. Methods: An online tool was developed to collect clinical information for 410 pts treated with adjuvant IM for ≥6 months for primary resectable KIT+GIST, discontinued, had a recurrence following discontiuation, and then restarted IM or initiated sunitinib. Data were collected at two specific time points: primary diagnosis and disease recurrence. Results: Pts were, on average, 60.2 years of age, mostly male, and Caucasian. At primary diagnosis, most pts had intermediate/high risk profiles based on Fletcher score. Pts received adjuvant IM for a median of 360 days for primary GIST before discontinuing trt; the first recurrence occurred 281 days after IM discontinuation. At the time of recurrence, most patients had a multifocal (62%), unresectable (45%) or metastatic (40%) tumor and did not have a surgery (80%). Most patients had intermediate/high risk profiles at recurrence. 23% of pts had a recurrence outside the gastrointestinal (GI) system (39% of pts initiated on sunitinib; 19% of those who restarted IM, p=<.001). 93% had recurrence inside the GI (85% of pts initiated on sunitinib; 95% of those who restarted IM; p=.002).The majoritiy of patients were restarted on IM (with surgery:74% without surgery:77%), with a 400mg dose (with surgery:79% without surgery: 63%). Conclusions: At the time of recurrence, most pts had high risk, unresectable/mestatstic multifocal tumor and re-started IM 400mg. [Table: see text]