Raut CP, et al. - Researchers sought to assess the tolerability and efficacy of 5 years of adjuvant imatinib mesylate therapy in patients with resected primary gastrointestinal stromal tumor. In this prospective, single-arm, phase 2 clinical trial (Postresection Evaluation of Recurrence-free Survival for Gastrointestinal Stromal Tumors With 5 Years of Adjuvant Imatinib [PERSIST-5]) of 91 adults, recurrence was not evident in any of the patients with resected imatinib-sensitive primary gastrointestinal stromal tumor who received 5 years of adjuvant therapy, while receiving imatinib. This suggests the efficacy of longer-duration adjuvant imatinib in appropriately selected patients with the resected primary gastrointestinal stromal tumor. However, the high (49%) rates of early discontinuation of imatinib highlight the challenges faced to maintain the adherence to the planned course of therapy despite its benefits.