Choi response criteria

Use only the size of the tumor during evaluation of response to chemotherapy has some pitfalls and limitations, especially when the estimated response for specific tumors such as gastrointestinal stromal tumor (GIST).

The Choi response criteria for GIST proposed that tumor attenuation could provide an additional measure of response to imatinib therapy. 

Complete response

• Disappearance of all target lesions  

Partial response

• ≥10% decrease tumor size at computed tomography (CT);
• or ≥15% decrease in tumor attenuation at computed tomography (CT);
• no new lesions 

Progressive disease

• ≥10% increase in sum of longest diameters (SLD) of lesions;
• does not meet the criteria for partial response by virtue of tumor attenuation, new intratumoral nodules,
• or an increase in the size of the existing intratumooral nodules 

Stable disease

• none of the above

See also

• RECIST