Choi Haesun, Charnsangavej Chuslip, de Castro Faria Silvana, Tamm Eric P, Benjamin Robert S, Johnson Marcella M, Macapinlac Homer A, Podoloff Donald A
Department of Diagnostic Imaging, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
AJR Am J Roentgenol. 2004 Dec;183(6):1619-28. doi: 10.2214/ajr.183.6.01831619.
We correlated changes in tumor density on CT with changes in glucose metabolism, or the maximum standardized uptake value (SUV(max)), on FDG PET and sought to develop CT imaging criteria that can be used to objectively evaluate tumor response in patients with metastatic gastrointestinal stromal tumors (GISTs) who undergo treatment with imatinib mesylate.
Using the criteria established by the Response Evaluation Criteria in Solid Tumors (RECIST) group, we selected 173 tumors (in 36 patients) for study. Tumor size and density were determined objectively, and overall tumor response (OTR) was evaluated subjectively on CT images. The changes in these parameters before and after treatment were correlated with changes in SUV(max).
Significant decreases were seen in both tumor density (mean, 12.3 H [16.5%]; p < 0.0001) and SUV(max) (mean, 3.43 [64.9%]; p < 0.0001). OTR evaluated subjectively, correlated well with changes in SUV(max) (p < 0.0001). No statistically significant association was found between changes in tumor density and changes in SUV(max) (p = 0.3088), but 70% (14/20) of the patients with tumors that showed response on FDG PET exhibited at least a partial response by a change in tumor density. Tumor size was found to have decreased significantly 2 months after treatment (p = 0.0070). However, in 75% of the patients, the disease was stable according to the traditional tumor response criteria of RECIST.
FDG PET is sensitive and specific for evaluating tumor response but cannot be used in patients whose baseline FDG PET results are negative for tumors. Although subjective evaluation was a better indicator of treatment response than was tumor density alone, the tumor density measurement is a good indicator and provides a reliable quantitative means of monitoring the tumor. RECIST, using only tumor size, was unreliable for monitoring GISTs during the early stage of imatinib mesylate treatment.
我们将CT上肿瘤密度的变化与氟代脱氧葡萄糖正电子发射断层扫描（FDG PET）上葡萄糖代谢变化或最大标准化摄取值（SUV(max)）进行关联，并试图制定CT成像标准，用于客观评估接受甲磺酸伊马替尼治疗的转移性胃肠道间质瘤（GIST）患者的肿瘤反应。
采用实体瘤疗效评价标准（RECIST）组制定的标准，我们选择了173个肿瘤（来自36例患者）进行研究。客观测定肿瘤大小和密度，并在CT图像上主观评估总体肿瘤反应（OTR）。治疗前后这些参数的变化与SUV(max)的变化相关联。
肿瘤密度（平均，12.3 H [16.5%]；p < 0.0001）和SUV(max)（平均，3.43 [64.9%]；p < 0.0001）均显著降低。主观评估的OTR与SUV(max)的变化相关性良好（p < 0.0001）。未发现肿瘤密度变化与SUV(max)变化之间存在统计学显著关联（p = 0.3088），但在FDG PET上显示有反应的肿瘤患者中，70%（14/20）通过肿瘤密度变化至少表现出部分反应。发现治疗2个月后肿瘤大小显著减小（p = 0.0070）。然而，根据RECIST的传统肿瘤反应标准，75%的患者疾病稳定。
FDG PET对评估肿瘤反应敏感且特异，但不能用于基线FDG PET肿瘤结果为阴性的患者。虽然主观评估比单独的肿瘤密度更能反映治疗反应，但肿瘤密度测量是一个良好指标，并提供了一种可靠的定量监测肿瘤的方法。仅使用肿瘤大小的RECIST在甲磺酸伊马替尼治疗早期监测GIST时不可靠。
