More GIST highlights from ASCO 2008
By Paula Vettel
LRG Science Team Member
Quantitative functional imaging by dynamic contrast enhanced ultrasonography (DCE-US) in patients with GIST treated by tyrosine kinase inhibitor
(TKI) L.Chami, N. Lassau, S. Koscielny, B. Benatsou, A. Roche, and A. Le Cesne (Institute Gustave Roussy)
The investigators have developed an ultrasound technique to study GIST tumors in 20 patients in France. Contrast was given, but no radiation was involved. Ultrasound was able to show the difference between live GIST and necrotic tissue. This is very useful in the early stages of drug treatment to measure efficacy of treatment. The study is being expanded to 650 patients with various solid tumors.
Cardiotoxicity associated with the cancer therapeutic agent sunitinib alate
Cardiotoxicity was studied in a group of 48 patients on Sutent therapy, including seven GIST patients. Grade 3-4 LVEF (Left Ventricular Ejection Fraction) (<40%) was found in 15 percent of patients. Of these, 81 percent were dosed at 50 mg for four weeks on and two weeks off, and 19 percent were dosed at 37.5 mg continuous. Identified risk factors were low body mass, congestive heart failure, and coronary heart disease. Most cardiac events were diagnosed in less than 100 days after the start of treatment. The authors recommend cardiac monitoring of patients on Sutent. Similar results were found in a previous study showing reduced LVEF and congestive heart failure in 11 percent of patients in Sutent clinical trials. (T. Chu, et.al; Lancet 2007; 370: 2011-2019)
Interobserver variability of size and density measurements on CT in patients with metastatic GISTs on imatinib mesylate (IM)
V. Bulusu, S. Fawcett, P. Moyle, and N. Carroll
The authors measured 27 GIST tumors from CT scans with contrast by longest measurement and tumor density in 2007. The same tumors were measured again three months after the start of drug therapy. In 2008, two of the authors repeated their measurements and assessments of the same tumors. The second set of measurements were within 10 percent of the original measurements in 81 to 92 percent of the cases for length and 81 to 88 percent for density. The authors feel that this variation is acceptable, but caution that these evaluations should be carried out by radiologists with experience in assessing response to drug therapy.
