Volumetric 3D CT analysis - an early predictor of response to therapy

Abstract

4576 Background: Evidence suggests that changes in unidimensional measurements (using RECIST criteria) may not accurately reflect actual changes in tumor size, and do not correlate well with other biomarkers of response, tumor progression, or patient outcome. We evaluated changes in tumor volume of target lesions with volumetric CT, and compared them with response assessments derived from RECIST criteria. Methods: We evaluated target lesions, including lymph node, liver, peritoneal and lung metastases in 25 patients with metastatic gastric cancer or gastroespohageal junction adenocarcinoma treated on a phase II clinical trial with irinotecan, cisplatin and bevacizumab. All patients underwent thin-section multidetector CT at baseline and 6-week follow-up for 10 cycles. Target lesions were measured unidimensionally and volumetrically, using validated automated and semiautomated segmentation algorithms. For initial analysis, correlation was made with the RECIST response using a cut-off value of 65% volume change. A ratio of change in RECIST measure to volume measure was calculated at time of maximal clinical response for each patient, as well as for responders versus non-responders. Results: 18 of 25 (72%) patients showed a clinical response. Of these 18 responders, 5, 6, 4, and 3 were identified as responders using RECIST criteria after cycles 1, 2, 3, and 4, respectively. Using a cut-off of 65% volume change, 14 of these responders were indentified after cycle 1, and 4 were identified after cycle 2. Using a cut-off value of 65%, volume measurements identified responders a mean of 50.3 days earlier than did RECIST criteria. There was a statistically significant (p<0.01) change in ratio of volume measurement change to RECIST measurement change for responding versus stable patients. Conclusions: Volumetric change in tumor size appears to predict clinical response earlier than do RECIST criteria in the majority of cases. Changes in volume are more sensitive because they exhibit a wider dynamic range. Ratios of size changes volumetrically appears to better discriminate RECIST responders from those with stable disease. Further work is needed to define the biologically relevant cut-off value for volume change, and to correlate volume change with other biomarkers. No significant financial relationships to disclose.

Volume-based growth tumor kinetics as a prognostic biomarker for patients with EGFR mutant lung adenocarcinoma undergoing EGFR tyrosine kinase inhibitor therapy: a case control study

“…Notably, Prasad et al [ 20 ] reported that volumetric measurement yields different results for treatment response in a considerable percentage of patients with liver metastases originating from breast cancer compared with that of uni-dimensional or bi-dimensional assessment. Despite the fact that volumetric measurements require a substantial amount of time and effort, this approach is nonetheless expected to improve decision making in the treatment of cancer due to its reproducibility and greater sensitivity for the diagnosis of disease progression [ 9 , 14 , 15 ]. Recently, the introduction of semi-automated or automated contour techniques using various software programs has made volumetric measurement easier and less time-consuming, which makes volumetric analysis feasible in a clinical setting.…”

Do Diametric Measurements Provide Sufficient and Reliable Tumor Assessment? An Evaluation of Diametric, Areametric, and Volumetric Variability of Lung Lesion Measurements on Computerized Tomography Scans

“…Importantly, computer-assisted measurements allow for more reproducible results when compared to other measurement techniques [ 13 , 15 ]. It has been shown that volume measurements may allow earlier recognition of tumor response to treatment and may predict clinical response earlier than RECIST [ 16 , 17 ]. However, most of these studies used small sample sizes.…”

MR-guided simultaneous integrated boost in preoperative radiotherapy of locally advanced rectal cancer following neoadjuvant chemotherapy

“…The methodological advantage of volumetry is measuring the volume compared to only measuring the longest diameter as in RECIST. Volumetry is not dependent of spherical tumour shapes and thus more sensitive to small volume changes [18,89], but is more time--consuming. However, considering the impact the result may have on the subsequent multidisciplinary treatment, the extra time seems justified: Good responders may be adequately treated with less extensive regimens, in addition to the important issues related to cutting costs and reducing morbidity, whereas poor responders may need intensified treatment to improve the outcome.…”