Gastrointestinal stromal tumors: case series of 29 patients defining the role of imatinib prior to surgery.

Background: The aim of this study was to assess the role of neoadjuvant imatinib in redefining treatment for gastrointestinal stromal tumors (GISTs).

Methods: A total of 76 patients were reviewed. Among them, 29 patients who were administered neoadjuvant imatinib for borderline resectable and locally advanced GISTs followed by surgery were analyzed. Adjuvant imatinib was administered based on risk stratification.

Results: The median age of the neoadjuvant imatinib group was 51 years. The median duration of neoadjuvant imatinib administration was 8.5 months. The response rate with neoadjuvant imatinib was 79.3%. Five patients, initially considered to have locally unresectable lesions, ultimately underwent resection (three R0, two R2). Another three patients, who had M1 disease, underwent R2 resection (due to the presence of metastasis) with complete resection of the primary lesion. In 19 patients, who would have originally required extensive surgery, underwent conservative surgery (R0). In two patients, neoadjuvant imatinib did not influence the final procedure. The postoperative complication rate was 13.8%, and there were no postoperative deaths. There was one locoregional recurrence and two cases of distant metastasis. The 1-, 2-, and 3-year overall survivals were each 100%.

Conclusions: Neoadjuvant imatinib for locally advanced GISTs is a safe concept for downsizing, improving resectability, and aiding organ-preserving surgery. It also improves the chance of long-term survival. Surgery, however, remains the cornerstone of curative treatment of GISTs even after neoadjuvant imatinib.