Tumor size alone not always best for gauging treatment response

Both PET and CT useful for judging biologic changes

Not only can positron emission tomography (PET) help evaluate treatmentfor gastrointestinal stromal tumors (GIST) by revealing biologicchanges such as how the tumor processes the fuel that makes it grow,but CT can indirectly reveal biologic changes as well by analyzing thetumor’s density, say researchers from The University of Texas M. D.Anderson Cancer Center in Houston.

For the study, researchers evaluated 173 GISTs–tumors that usuallybegin in the wall of the GI tract–in 36 patients who had undergone aprotein enzyme inhibitor treatment, 29 of which underwent both CT andPET. In those 29 patients, the researchers found a high correlationbetween the tumor responses based on tumor density and changes ininternal characteristics of the tumors shown on CT and the changes inglucose metabolism of the tumors shown on PET.

Full Text at: http://www.eurekalert.org/pub_releases/2004-12/arrs-tsa120604.php