(P 45) THE LONG-TERM EFFECT OF IMATINIB WITH HEPATIC RESECTION OR OTHER LOCAL TREATMENT FOR GIST LIVER METASTASES

Objective: This retrospective study evaluates the long-term survival benefits of combining imatinib mesylate (IM) treatment with hepatic resection (HR) or other local therapies, radiofrequency ablation (RFA), and transarterial chemoembolization (TACE), in comparison to IM treatment alone in patients with liver metastasis from gastrointestinal stromal tumors (GISTs).

Methods: This study included 238 patients diagnosed with liver metastasis of GIST between January 2002 and April 2022 in the First Affiliated Hospital of Sun Yat-Sen University. The oncology outcomes of concern included overall survival (OS) and progress-free survival (PFS) and liver-specific progression-free survival (liver-specific PFS).

Results: Of the 238 patients(Table 1), 126 were treated with IM alone(IM group), 81 with IM combined with HR (IM+HR group), and 31 with IM combined with RFA/TACE (IM+RFA/TACE group). The median follow-up time was 100.3 months. The median OS in the IM group was 132.6 months(Figure 1), while it was not reached in both the IM+HR group and the IM+RFA/TACE group. The 10-year OS rate of the IM+HR group was significantly higher than that of the IM and IM+RFA/TACE groups (91.8% vs 61.1% vs 55.2%, respectively, p=0.015). The liver-specific PFS (p=0.642) and overall PFS (p=0.369) of the three groups showed a beneficial trend in the combined treatment group. Multivariate analyses revealed that age ≤60 years (HR 0.280, p=0.000) and IM+HR (HR 0.361, p=0.047) were independently associated with better OS (Table 2). In the comparison of IM+HR and IM+RFA/TACE groups, surgical intervention achieving no evidence of disease (NED) was independently associated with better OS (HR 0.099, p=0.034), liver-specific PFS (HR 0.428, p=0.033), and better PFS (HR 0.402, p=0.004)(Table 3,4,5 ).

Conclusion: In patients with GIST liver metastases, IM combined with HR significantly prolonged OS compared with IM alone and IM combined with RFA/TACE, while OS was similar in IM combined with RFA/TACE and IM alone. Achieving NED status in surgical treatment significantly prolongs the patient's OS, liver-specific PFS, and PFS.