Successful GIST management requires appropriate assessment of radiographic imaging; however, imaging in GIST can be challenging.

• Watch video demonstration for a concise overview of interpreting radiologic images of responses to TKI therapy in KIT+ GIST.

• Standard definitions of response and progression (RECIST) criteria* have been shown to be insensitive in evaluating response of GISTs to treatment^1,2
  • In 1 study, a majority of patients who were classified as having stable disease by RECIST criteria were shown to have a grade 4 response (a 99% reduction in glucose metabolism) by positron emission tomography (PET)¹
• New criteria that take into account tumor density have been proposed by Choi et al^1,2
  • The Choi criteria—a 10% decrease in unidimensional tumor size or a 15% reduction in tumor density—have been shown to correlate well with a good response by PET and are more predictive of time to tumor progression than response by RECIST²

• Computerized tomography (CT): the standard imaging modality in GIST; provides information on tumor size and density
• Positron emission tomography (PET, FDG-PET): measures glucose uptake; provides information about the metabolic activity of tumors. FDG-PET
  scans should be used in addition to CT scans but not as a replacement