Pre-progression Surgery Added to Imatinib is Associated with Prolonged Survival in Oligometastatic GIST: A Covariate-Matched Study.

BACKGROUND: The role and optimal timing of surgery in oligometastatic gastrointestinal stromal tumors (GIST) remain controversial. We evaluated whether pre‑progression surgery added to first‑line imatinib improves survival in oligometastatic GIST. METHODS: We retrospectively analyzed 179 patients with metastatic/recurrent GIST treated with first‑line imatinib. Oligometastasis was defined as ≤ 3 lesions and ≤ 2 organs. Covariate matching (1:1 nearest-neighbor matching on covariates, caliper = 0.05) was performed among oligometastatic patients receiving imatinib alone (Group A) versus imatinib plus pre‑progression surgery (Group B1). Outcomes were compared by using Kaplan‑Meier, log‑rank/Gehan-Breslow-Wilcox, restricted mean survival time (RMST), and Cox regression. RESULTS: Among 179 patients, 90 (50.3%) had oligometastasis. In the imatinib‑alone subgroup, oligometastatic and polymetastatic patients had similar survival (PFS: P = 0.693; overall survival [OS]: P = 0.237). After matching (29 pairs), pre-progression surgery was associated with significantly prolonged OS (HR = 0.16, P = 0.007) and provided clinically meaningful PFS benefit (median 104 vs. 29 months; HR = 0.48; log-rank P = 0.041). Restricted mean survival time analysis at 120 months showed additional 32.97 months of PFS (P = 0.007) and 30.88 months of OS (P = 0.003). These findings were robust across all sensitivity analyses. CONCLUSIONS: Pre-progression surgery added to first-line imatinib was associated with significantly prolonged OS and provides clinically meaningful PFS benefit in oligometastatic GIST. Surgical evaluation should be actively considered in imatinib‑sensitive oligometastatic disease.