Is there a role for discontinuing imatinib in patients with advanced gastrointestinal stromal tumour?

Imatinib is the standard first-line treatment of patients with gastrointestinal stromal tumour in advanced phase. In this setting, the optimal duration of treatment is not known, and it is generally considered that treatment should be given until progression or intolerance.

The BFR14 randomized trial tested the discontinuation of imatinib at 1 and 3 years and demonstrated that treatment discontinuation at these time points is associated with a median progression-free survival of 6 months. Discontinuation is now tested at 5 years in this trial. The capacity of adjuvant imatinib to reduce the risk of relapse in localized gastrointestinal stromal tumours of sizes more than 3 cm was demonstrated in the ACOSOG Z9001. However, the risk of relapse beyond the 1 year of adjuvant imatinib remained substantial, and longer treatment duration may be needed. Finally, in patients having exhausted all therapeutic options in advanced phase, the role of a continuous maintenance treatment with TKI even in those who failed the treatment has been proposed as an option in the recent European Society of Medical Oncology and National Comprehensive Cancer Network guidelines, though a formal demonstration of its impact on survival is lacking.

In advanced gastrointestinal stromal tumour, imatinib should be given until progression or intolerance and possibly after progression when patients have exhausted all other options. In the adjuvant setting, the optimal duration of imatinib treatment remains unknown.