Tumor Volume as an Alternative Response Measurement for Imatinib Treated GIST Patients
article
Background: Assessment of tumor size changes is crucial in clinical trials and patient care. We compared imatinib-induced volume changes of liver metastases (LM) from gastro-intestinal stromal tumors (GIST) to RECIST and Choi criteria and their association with overall survival (OS).
Methods: LM from 84 GIST patients (training and validation set) were evaluated using manual and semi-automated Computed Tomography measurements at baseline, after 3, 6 and 12 months of imatinib. The ability of uni-dimensional (1D) and three-dimensional (3D) measurements to detect size changes (increase/decrease) >/=20% was evaluated. Volumetric response cut-offs were derived from minimally relevant changes (+20/230%) by RECIST, considering lesions as spherical or ellipsoidal.
Results: 3D measurements detected size changes >/=20% more frequently than 1D at every time-point (P>/=0.008). 3D and Choi criteria registered more responses than RECIST at 3 and 6 months for 3D-spheres (P>/=0.03) and at all time-points for 3D-ellipsoids and Choi criteria (P<0.001). Progressive disease by 3D criteria seems to better correlate to OS at late timepoints than other criteria.
Conclusion: Volume criteria (especially ellipsoids) classify a higher number of patients as imatinib-responders than RECIST.
Volume discriminates size changes better than diameter in GIST and constitutes a feasible and robust method to evaluate response and predict patient benefit.
Methods: LM from 84 GIST patients (training and validation set) were evaluated using manual and semi-automated Computed Tomography measurements at baseline, after 3, 6 and 12 months of imatinib. The ability of uni-dimensional (1D) and three-dimensional (3D) measurements to detect size changes (increase/decrease) >/=20% was evaluated. Volumetric response cut-offs were derived from minimally relevant changes (+20/230%) by RECIST, considering lesions as spherical or ellipsoidal.
Results: 3D measurements detected size changes >/=20% more frequently than 1D at every time-point (P>/=0.008). 3D and Choi criteria registered more responses than RECIST at 3 and 6 months for 3D-spheres (P>/=0.03) and at all time-points for 3D-ellipsoids and Choi criteria (P<0.001). Progressive disease by 3D criteria seems to better correlate to OS at late timepoints than other criteria.
Conclusion: Volume criteria (especially ellipsoids) classify a higher number of patients as imatinib-responders than RECIST.
Volume discriminates size changes better than diameter in GIST and constitutes a feasible and robust method to evaluate response and predict patient benefit.
TNO Identifier
465641
Source
PLoS ONE, 7(11)
Article nr.
e48372