Surgical treatment in patients with advanced gastrointestinal stromal tumours (GISTs) in second-line and later stages: A single-centre cohort study.

818 Background: Gastrointestinal stromal tumour (GIST) after imatinib treatment failure usually progresses rapidly with limited overall survival. Previous studies have suggested that surgery is beneficial for advanced GISTs in disease control to imatinib, but the role of surgery in > = 2 line patients remains unclear. Methods: Imatinib-resistant patients with advanced GIST between May 2009 and Nov. 2023 were included. Surgical treatments included tumour reduction, radiofrequency ablation and TACE. The primary endpoint was overall survival (OS) and secondary endpoints were time to second-line treatment failure (TTF) and postoperative morbidity. To balance clinicopathological characteristics, 1:1 propensity score matching (PSM) was used. Results: A total of 242 patients with advanced GIST treated with 2nd-line or later drugs were included, including 125 in the surgical group and 117 in the non-surgical group. The median follow-up was 30.3 months. OS was significantly better in the surgical group than in the non-surgical group (pre-PSM: 51.7m vs 35.9m , p = 0.001; post-PSM: 50.8m vs 38.8m, p = 0.043). Univariate analysis showed that surgical treatment (HR 0.487, 95% CI 0.320-0.740, p = 0.001), age ≤60 years (HR 0.640, 95% CI 0.411-0.997, p = 0.049) and low tumour burden (HR 0.491, 95% CI 0.293-0.822, p = 0.007) were associated with prolonged OS. Multivariate analysis indicated that surgical treatment (HR 0.541, 95% CI 0.348-0.843, p = 0.007) and low tumour burden (HR 0.510, 95% CI 0.300-0.865, p = 0.012) were significantly associated with OS benefit. Patients (n = 84) who had surgical treatment during second-line treatment had longer TTF compared to patients (n = 158) who had TKI only (14.2m vs 8.1m , p = 0.003). There were 29 (14.8%) postoperative complications with Clavien-Dindo classification ≥3, including 5 deaths. Conclusions: Surgical treatment can provide a survival benefit for patients with second-line and later advanced GIST, but further studies are needed for a more detailed indication of the surgical population.