Radical Resection Versus Organ‐Preserving Local Excision for Rectal Gastrointestinal Stromal Tumor: The Role of Neoadjuvant Imatinib

BACKGROUND: Rectal gastrointestinal stromal tumors (GISTs) are rare, and their optimal surgical management remains controversial. This study compared clinicopathologic features and oncologic outcomes between total mesorectal excision (TME) and local excision (LE) to guide surgical strategy. METHODS: We retrospectively analyzed 128 patients who underwent surgery for rectal GIST at Asan Medical Center between January 2000 and April 2023. Recurrence-free survival (RFS), overall survival (OS), and tumor downsizing were evaluated. Survival was measured from surgery or imatinib initiation in patients receiving neoadjuvant imatinib. RESULTS: Of 128 patients, 43(33.6%) underwent TME and 85(66.4%) underwent LE. Tumors > 5 cm and neoadjuvant imatinib use were more common with TME, whereas tumors < 2 cm and R0 resection were more frequent with LE. The 5-year RFS did not differ significantly between the LE and TME groups (98.8% vs. 92.6%, p = 0.184), whereas 5-year OS was higher after LE (96.8% vs. 92.1%, p = 0.047). Neoadjuvant imatinib reduced mean tumor diameter from 64.9 ± 23.5 mm to 49.2 ± 19.3 mm (p < 0.001). CONCLUSION: LE may provide acceptable recurrence control and potential functional advantages in selected patients. For large rectal GISTs, LE may be considered after adequate tumor downsizing with neoadjuvant imatinib.