CT and PET: Early Prognostic Indicators of Response to Imatinib Mesylate in Patients with Gastrointestinal Stromal Tumor

Holdsworth, C.H.; Badawi, Ramsey D.; Manola, Judith; Kijewski, Marie Foley; Israel, David; Demetri, George D.; Abbeele, Annick D. Van den

doi:10.2214/ajr.07.2496

Cited by 160 publications

(94 citation statements)

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“…For example, PET studies demonstrate a response as early as 24 hours after the start of imatinib mesylate treatment for gastrointestinal stromal tumor and after 1 cycle of chemotherapy for non-Hodgkin lymphoma or nonsmall cell lung cancer. [15][16][17] Although numerous studies have been done worldwide, these generally have involved small numbers of patients (<100) from single centers. Multicenter trials with hundreds of patients currently are underway studying the utility of PET in directing therapy in lymphoma and lung cancer.…”

Section: Discussionmentioning

confidence: 99%

The impact of positron emission tomography (PET) on expected management during cancer treatment

Hillner

Siegel

Shields

et al. 2009

Cancer

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BACKGROUND:Positron emission tomography (PET) performed during cancer therapy (treatment monitoring) has shown promise for predicting treatment outcome. However, when used for this purpose, PET generally is not considered standard care. Under the Medicare ‘coverage with evidence development’ policy, PET (and integrated PET/computed tomography) became a covered service for treatment monitoring if prospective registry data were collected.METHODS:The National Oncologic PET Registry collected questionnaire data on intended patient management before and after PET. Data were available from 8240 patients who had 10,497 treatment‐monitoring PET scans at 946 centers; these studies were used to monitor chemotherapy alone (82%), radiation therapy alone (6%), or combined‐modality treatment (12%). Ovarian, pancreatic, and lung cancers accounted for 37% of the cohort. In 54% of scans, the pre‐PET summary stage was metastatic disease.RESULTS:If PET had not been available, then the pre‐PET plan would have been other imaging (53%), ongoing treatment (41%), or biopsy or watching (6%). Change in the post‐PET intended management was similar in the imaging and treatment groups: 26% to 28% of scans to switching to another therapy, and 16% to 19% scans led to adjustment of the dose or duration of therapy. Changes in management were more frequent if the referring physician judged that the post‐PET prognosis was worse rather than improved or unchanged (78% vs 40%). The physicians indicated that PET enabled 91% of their patients to avoid future tests.CONCLUSIONS:Physicians often report plans to modify their therapeutic plans in elderly cancer patients when PET is used for treatment monitoring. Cancer 2009. © 2009 American Cancer Society.

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Section: Discussionmentioning

confidence: 99%

The impact of positron emission tomography (PET) on expected management during cancer treatment

Hillner

Siegel

Shields

et al. 2009

Cancer

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“…FDG uptake thresholds of 40% to 69% decrease compared to baseline were used to report treatment response. [41][42][43][44][45] Nonresponders also are identified. 46 Patients who had little FDG uptake after treatment had the expected better survival also.…”

Section: Gastric Cancermentioning

confidence: 99%

PET Imaging for Treatment Response in Cancer

Eary

2008

PET Clinics

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KeywordsPET; FDG; Cancer imaging; Response imaging PET tumor surveys have become widely used in clinical practice. [F-18] fluorodeoxyglucose (FDG) is the most commonly used radiotracer for clinical indication of tumor staging and restaging after treatment. FDG PET consistently has exhibited better diagnostic performance than conventional imaging in adults and pediatric populations. [1][2][3][4] More recently, a growing body of literature is reporting the use of FDG and other PET imaging agents in treatment response assessment. [5][6][7] In many cases, FDG PET has proved to be a reliable means of noninvasively observing response in various treatments.Additionally, reliable determination of past treatment changes, including recurrent tumors and differentiation of benign and malignant lesions, will reduce morbidity and the cost of care in anatomic imaging. The Response Evaluation Criteria in Solid Tumors (RECIST) are a useful means to report quantitative changes in tumor size on CT scans in many different tumors in response to treatment. 8,9,10 Many tumor types, however, do not change size appreciably in response to treatment. Early changes that may indicate treatment regimen effectiveness also may not result in tumor change in size. FDG PET is a relatively sensitive indicator of treatment response in many tumors, indicating changes in metabolism that often precede or take the place of tumor size change. Fig. 1 shows some examples of FDG PET tumor response.Recently, several cooperative groups have addressed the use of FDG PET as a biomarker for cancer treatment response. An early report by the European Organization for Research and Treatment of Cancer (EORTC) set criteria for treatment response according to changes in tumor FDG uptake compared to baseline. 2 These criteria include:Complete response (CR)- [F-18] fluorodeoxyglucose uptake is comparable to baseline activity in all lesions Partial response (PR)-all target lesions have greater than 25% decrease in standardized uptake variable (SUV) Stable disease (SD)-target lesions have less than 25% increase or decrease in SUV Progressive disease (PD)-at least one target lesion has greater than 25% increase in SUV, or new lesions appear (regardless of SUV changes in target lesions)These criteria are in wide use today for clinical FDG PET imaging. A set of criteria for clinically significant changes in tumor FDG uptake, however, is based on consistent parameters for the FDG PET acquisition between studies in the same patient, and between patient imaging groups at different institutions. Development and evaluation of new cancer therapies could be enhanced by a set of validated biomarkers for treatment response. FDG PET meets these criteria in clinical studies, if imaging studies are conducted with patients on clinical therapeutic trials in a reliable and consistent manner. 3 To address the consistency in FDG PET data for use as NIH Public Access A review of cancer treatment response begins with consideration of the pathological basis of the tumor process. Tumors are c...

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“…This reduction in rate of size change both exacerbates the problems associated with unidimensional measurement error and further calls into question the four-state classifier associated with the RECIST methodology since imprecise measures of tumor dimensions and inappropriate classifications may lead to incorrect assessment of treatment efficacy. 10 Test repeatability may potentially be improved by determining tumor volume rather than SLD. 11 This has been previously used with some success in studies involving neurological disorders 12 and in the lung 13,14 leading to the notion that this specific metric can be extended for use in other parts of the body ͑for example, in oral cavity carcinoma 15 …”

Section: Introductionmentioning

confidence: 99%

Comparison of two‐dimensional and three‐dimensional iterative watershed segmentation methods in hepatic tumor volumetrics

et al. 2008

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In this work the authors compare the accuracy of two-dimensional ͑2D͒ and three-dimensional ͑3D͒ implementations of a computer-aided image segmentation method to that of physician observers ͑using manual outlining͒ for volume measurements of liver tumors visualized with diagnostic contrast-enhanced and PET/CT-based non-contrast-enhanced ͑PET-CT͒ CT scans. The method assessed is a hybridization of the watershed method using observer-set markers with a gradient vector flow approach. This method is known as the iterative watershed segmentation ͑IWS͒ method. Initial assessments are performed using software phantoms that model a range of tumor shapes, noise levels, and noise qualities. IWS is then applied to CT image sets of patients with identified hepatic tumors and compared to the physicians' manual outlines on the same tumors. The repeatability of the physicians' measurements is also assessed. IWS utilizes multiple levels of segmentation performed with the use of "fuzzy regions" that could be considered part of a selected tumor. In phantom studies, the outermost volume outline for level 1 ͑called level 1_1 consisting of inner region plus fuzzy region͒ was generally the most accurate. For in vivo studies, the level 1_1 and the second outermost outline for level 2 ͑called level 2_2 consisting of inner region plus two fuzzy regions͒ typically had the smallest percent error values when compared to physician observer volume estimates. Our data indicate that allowing the operator to choose the "best result" level iteration outline from all generated outlines would likely give the more accurate volume for a given tumor rather than automatically choosing a particular level iteration outline. The preliminary in vivo results indicate that 2D-IWS is likely to be more accurate than 3D-IWS in relation to the observer volume estimates.

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CT and PET: Early Prognostic Indicators of Response to Imatinib Mesylate in Patients with Gastrointestinal Stromal Tumor

Abstract: The two best metrics were the optimized PET SUVmax threshold of 3.4 at 1 month (p = 0.00002) and the optimized CT bidimensional measurement threshold (no growth from baseline to 1 month, p = 0.00005) in this patient group.

Cited by 160 publications

References 21 publications

The impact of positron emission tomography (PET) on expected management during cancer treatment

The impact of positron emission tomography (PET) on expected management during cancer treatment

PET Imaging for Treatment Response in Cancer

Comparison of two‐dimensional and three‐dimensional iterative watershed segmentation methods in hepatic tumor volumetrics

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