Can Imatinib Be Safely Withdrawn in Patients with Surgically Resected Metastatic GIST?

Patients with advanced gastrointestinal stromal tumors (GIST) are currently recommended for treatment with tyrosine kinase inhibitors (TKI) in a life-long sequence. The standard first-line treatment is imatinib mesylate (IM), which is switched to other drugs at progression or if the patient does not tolerate IM. This strategy has served many patients well as patients with advanced GIST now live for a median of approximately 5 years, compared to 18 months prior the TKI era. The prevailing hypothesis is that IM and other TKIs fail to completely eradicate metastatic GIST and that progression is inevitable if IM treatment is discontinued. Following a response to IM and surgery of metastatic lesions harbouring foci responsible for drug resistance and subsequent clinical relapse, we hypothesize that this may lead to a cure and the justification to stop IM in selected patients. We suggest that this novel strategy, a priori, warrants further investigation. We reviewed the available literature, present three clinical cases and put forward for discussion a treatment algorithm that needs confirmation within the context of a prospective clinical study.