Background: Although benefits of surgical resection of residual gastrointestinal stromal tumors (GISTs) after imatinib therapy have been suggested, those benefits over imatinib alone have not been proven. We compared the clinical outcomes of surgical resection of residual lesions after imatinib treatment (S group) with imatinib treatment alone (NS group) in patients with recurrent or metastatic GISTs.
Methods: A total of 134 patients (42 in the S group, 92 in the NS group) with recurrent or metastatic GIST who had stable disease for more than 6 months after responding to imatinib were included.
Results: There were no statistically significant differences in the baseline characteristics of the S and NS groups except for age and number of peritoneal metastases. The median follow-up period was 58.9 months. Progression-free survival (PFS) and overall survival (OS) were significantly longer in the S group compared with the NS group (median PFS: 87.7 vs. 42.8 months, p = 0.001; median OS: not reached vs. 88.8 months, p = 0.001). Multivariate analysis revealed that S group, female sex, KIT exon 11 mutations, and low initial tumor burden were associated with longer PFS, and S group and low initial tumor burden were associated with a longer OS. Even after applying inverse probability of treatment weighting adjustment, the S group demonstrated significantly better outcomes in terms of PFS (HR 2.326; 95 % confidence interval [CI] 1.034-5.236; p = 0.0412) and OS (HR 5.464; 95 % CI 1.460-20.408; p = 0.0117).
Conclusion: Surgical resection of residual lesions after disease control with imatinib is likely to be beneficial to patients with recurrent or metastatic GISTs.