Optimal Duration of Adjuvant Therapy for Patients With Resected Gastrointestinal Stromal Tumors

Blanke talks about the study by Joensu et al that report the results of Scandinavian Group SSGXVIII trial, a randomized phase 3 trial comparing 12 vs. 36 months of adjuvant imatinib (400 mg per day), administered following tumor resection to patients deemed to be at high risk for gastrointestinal stromal tumor (GIST) recurrence. Patients who received drug for the longer period experienced better relapse-free survival and overall survival compared with patients who received the drug for 12 months. Despite the inevitable minor flaws in study design, 36 months of imatinib treatment immediately became preferred therapy in much of North America, Europe, and Asia. The trial also raised interesting theoretical and practical questions, including (1) whether the treatment will actually cure patients with residual micrometastatic GIST vs. solely delaying recurrence; (2) whether 36 months of adjuvant therapy is long enough to achieve the best possible outcome; and (3) how to perform clinical studies to determine the optimal duration for administration of postoperative biologic agents, which do not seem to fit the models developed for adjuvant cytotoxic chemotherapy.