Does imatinib help all GIST patients?
About 85% of patients experience benefit from imatinib (Gleevec). Oncologists use a description system called RECIST (Response Criteria in Solid Tumors) to categorize tumor responses to treatments (Therasse et al, 2000). The categories are: • Complete response (CR): tumor is no longer detectable. • Partial response (PR): a decrease of 30% or more in the longest dimension of a single tumor or in the sum of the longest dimensions of a group of target lesions. • Stable disease (SD): a decrease of less than 30% in the longest dimension of a single tumor (or summed dimensions of a group of tumors) or an increase of less than 20% in the same dimension (or sum). • Progressive disease (PD): an increase of at least 20% in the monitored longest dimension (or sum). The tumor “best response” results from all the available trials of imatinib are summarized in the following table. The results may vary partly as a function of the duration of follow-up, since some tumors may take a long time to show e
