Cytoreductive Surgery in Patients with Metastatic Gastrointestinal Stromal Tumor Treated with Sunitinib Malate

Background. In patients with metastatic gastrointestinal stromal tumor (GIST) on first-line imatinib (IM) undergoing cytoreductive surgery, response to IM at time of surgery correlates with completeness of resection and progression-free and overall survival (PFS, OS). Impact of surgery in IM-resistant patients on second-line sunitinib (SU) is unknown. Methods. Patients on SU undergoing surgery for metastatic GIST at our institution were reviewed. Response to SU at time of surgery was categorized as responsive disease (RD), limited progression (LP) or generalized progression (GP). Results. Fifty patients underwent surgery after a median 6.7 months of SU. Forty patients (80%) had prior surgery at initial presentation of GIST; 16 (32%) underwent prior surgery on IM. At time of surgery on SU, 10 patients (20%) had RD, 22 (44%) had LP, and 18 (36%) had GP. Resections were macroscopically complete in 25 patients (50%); completeness of resection did not correlate with response to SU. Complication rate was 54%; reoperations were required in 16%. Median PFS after surgery and start of SU was 5.8 and 15.6 months, respectively (median follow-up 15.2 months). Corresponding median OS was 16.4 and 26.0 months, respectively. Differences in PFS and OS based on response to SU were not significant. Younger age was prognostic of survival. Conclusion. Surgery is feasible in patients with metastatic GIST on SU, but incomplete resections are frequent and complication rates are high. Relevance of survival rates is difficult to assess given the selection bias. Benefits of surgery should be weighed against symptoms and alternative treatments.