Project description:OBJECTIVE::To examine the prognostic value of fluorodeoxyglucose (FDG) and fluorothymidine (FLT) interim positron emission tomography/CT (PET/CT) for diffuse large B-cell lymphoma (DLBCL). METHODS::44 patients with newly diagnosed DLBCL underwent both fluorine 18 FDG (18F-FDG) and 18F-FLT PET/CT scans at baseline and after two cycles of a rituximab-containing chemotherapy regimen. Maximum standard uptake values (SUVmax) and changes in SUV (?SUV) were calculated for both tracers for the predominant lesion of each patient, for prediction of progression-free survival (PFS) and overall survival (OS). RESULTS::The median follow-up period was 71 months. Receiver operating characteristic (ROC) analysis indicated that the best ?SUV cut-off values for FDG (?SUVFDG) and FLT (?SUVFLT) were 79 and 76%, respectively. A ?SUVFLT cut-off of 76% had the highest significance for prediction of PFS (p = 0.003) and OS (p = 0009), with sensitivity, specificity, and accuracy of 80.0, 85.7, and 81.8% respectively in response assessment. CONCLUSION::Interim FLT PET/CT had higher specificity and accuracy than standard FDG PET/CT-based interpretation. ADVANCES IN KNOWLEDGE::This study demonstrated that interim FLT PET/CT had higher accuracy than standardized FDG-based interpretation for therapeutic response assessment in DLBCL. FLT had the advantage of potentially reducing false positive of interim FDG PET/CT.
Project description:FDG PET is effective in treatment response evaluation of cancer. However, there is no standard method for quantitative evaluation of FDG PET, particularly regarding cytostatic drugs. We compared various FDG PET quantitative methods in terms of response determination.A total of 39 refractory metastatic colorectal cancer patients who received a multikinase inhibitor treatment were included. Baseline and posttreatment FDG PET/CT scans were performed before and two cycles after treatment. Standardized uptake value (SUV) and total lesion glycolysis (TLG) values using various margin thresholds (30-70 % of maximum SUV with increment 10 %, twice mean SUV of blood pool, SUV 3.0, and SUV 4.0) were measured, with measurement target of the hottest lesion or a maximum of five hottest lesions. Treatment response by the PERCIST criteria was also determined. Predictive values of the PET indexes were evaluated in terms of the treatment response determined by the RECIST 1.1 criteria.The agreement rate was 38 % between response determined by the PERCIST and the RECIST criteria (??=?0.381). When patients were classified into disease control group (PR, SD) and non-control group (PD) by the RECIST criteria, percent changes of TLG with various margin thresholds (particularly, 30-50 % of maximum SUV) exhibited significant differences between the two groups, and high diagnostic power for the response by the RECIST criteria. TLG-based criteria, which used a margin threshold of 50 % of maximum SUV, exhibited a high agreement with the RECIST criteria compared with the PERCIST criteria (??=?0.606).In metastatic colorectal cancer, FDG PET/CT could be effective for treatment response evaluation by using TLG measured by margin thresholds of 30-50 % of maximum SUV. Further studies are warranted regarding the optimal cutoff values for this method.
Project description:18F-fluorodeoxyglucose positron emission tomography with integrated computed tomography (FDG-PET/CT) and contrast-enhanced computed tomography (CT) can be used for response evaluation in metastatic breast cancer (MBC). In this study, we aimed to review literature comparing the PET Response Criteria in Solid Tumors (PERCIST) with Response Evaluation Criteria in Solid Tumors (RECIST) in patients with MBC. We made a systematic search in Embase, PubMed/Medline, and Cochrane Library using a modified PICO model. The population was MBC patients and the intervention was PERCIST or RECIST. Quality assessment was performed using the QUADAS-2 checklist. A total of 1975 articles were identified. After screening by title/abstract, 78 articles were selected for further analysis of which 2 duplicates and 33 abstracts/out of focus articles were excluded. The remaining 43 articles provided useful information, but only one met the inclusion and none of the exclusion criteria. This was a retrospective study of 65 patients with MBC showing one-year progression-free survival for responders versus non-responders to be 59% vs. 27% (<i>p</i> = 0.2) by RECIST compared to 64% vs. 0% (<i>p</i> = 0.0001) by PERCIST. This systematic literature review identified a lack of studies comparing the use of RECIST (with CE-CT) and PERCIST (with FDG-PET/CT) for response evaluation in metastatic breast cancer. The available sparse literature suggests that PERCIST might be more appropriate than RECIST for predicting prognosis in patients with MBC.
Project description:The aim of this study was to compare fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) and contrast-enhanced computed tomography (CE-CT) for the prediction of progression-free survival (PFS) and disease-specific survival (DSS) in patients with stage IV breast cancer undergoing systemic therapy.Sixty-five patients with metastatic breast cancer treated with first- or second-line systemic therapy in prospective clinical trials were included. Response to treatment was evaluated by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 for CE-CT and by PET Response Criteria in Solid Tumors (PERCIST), respectively.All responders by RECIST (n = 22) were also responders by PERCIST, but 40% (17/43) of non-responders by RECIST were responders by PERCIST. Responses according to RECIST and PERCIST both correlated with PFS, but PERCIST showed a significantly higher predictive accuracy (concordance index for PFS: 0.70 vs. 0.60). One-year PFS for responders vs. non-responders by RECIST was 59% vs. 27%, compared to 63% vs. 0% by PERCIST. Four-year DSS of responders and non-responders by RECIST was 50% and 38%, respectively (p = 0.2, concordance index: 0.55) as compared to 58% vs. 18% for PERCIST (p < 0.001, concordance index: 0.65). Response on PET/CT was also a significantly better predictor for DSS than disease control on CE-CT.In patients with metastatic breast cancer, tumor response on PET/CT appears to be a superior predictor of PFS and DSS than response on CE-CT. Monitoring tumor response by PET/CT may increase the power of clinical trials using tumor response as an endpoint, and may improve patient management in clinical routine.
Project description:The purpose of this study was to evaluate 18F-FDG PET/CT scanning as an early predictor of response to immune checkpoint inhibitors (ICIs) in patients with advanced melanoma. Methods: Twenty patients with advanced melanoma receiving ICI prospectively underwent 18F-FDG PET/CT at 3 scan intervals: before treatment initiation (SCAN-1), at days 21-28 (SCAN-2), and at 4 mo (SCAN-3). This study was approved by the institutional review board, and informed consent was received from all patients who were enrolled between April 2012 and December 2013. Tumor response at each posttreatment time point was assessed according to RECIST 1.1, immune-related response criteria, PERCIST (PERCIST 1.0), and European Organization for Research and Treatment of Cancer (EORTC) criteria. Performance characteristics of each metric to predict best overall response (BOR) at ? 4 mo were assessed. Results: Twenty evaluable patients were treated with ipilimumab (n = 16), BMS-936559 (n = 3), or nivolumab (n = 1). BOR at ? 4 mo included complete response (n = 2), partial response (n = 2), stable disease (n = 1), and progressive disease (n = 15). Response evaluations at SCAN-2 using RECIST 1.1, immune-related response criteria, PERCIST, and EORTC criteria demonstrated accuracies of 75%, 70%, 70%, and 65%, respectively, to predict BOR at ? 4 mo. Interestingly, the optimal PERCIST and EORTC threshold values at SCAN-2 to predict BOR were >15.5% and >14.7%, respectively. By combining anatomic and functional imaging data collected at SCAN-2, we developed criteria to predict eventual response to ICI with 100% sensitivity, 93% specificity, and 95% accuracy. Conclusion: Combining functional and anatomic imaging parameters from 18F-FDG PET/CT scans performed early in ICI appears predictive for eventual response in patients with advanced melanoma. These findings require validation in larger cohorts.
Project description:BACKGROUND:Despite the significant upgrading in recent years of the role of 18F-FDG PET/CT in multiple myeloma (MM) diagnostics, there is a still unmet need for myeloma-specific radiotracers. 3'-Deoxy-3'-[18F]fluorothymidine (18F-FLT) is the most studied cellular proliferation PET agent, considered a potentially new myeloma functional imaging tracer. The aim of this pilot study was to evaluate 18F-FLT PET/CT in imaging of MM patients, in the context of its combined use with 18F-FDG PET/CT. RESULTS:Eight patients, four suffering from symptomatic MM and four suffering from smoldering MM (SMM), were enrolled in the study. All patients underwent 18F-FDG PET/CT and 18F-FLT PET/CT imaging by means of static (whole body) and dynamic PET/CT of the lower abdomen and pelvis (dPET/CT) in two consecutive days. The evaluation of PET/CT studies was based on qualitative evaluation, semi-quantitative (SUV) calculation, and quantitative analysis based on two-tissue compartment modeling. 18F-FDG PET/CT demonstrated focal, 18F-FDG avid, MM-indicative bone marrow lesions in five patients. In contrary, 18F-FLT PET/CT showed focal, 18F-FLT avid, myeloma-indicative lesions in only two patients. In total, 48 18F-FDG avid, focal, MM-indicative lesions were detected with 18F-FDG PET/CT, while 17 18F-FLT avid, focal, MM-indicative lesions were detected with 18F-FLT PET/CT. The number of myeloma-indicative lesions was significantly higher for 18F-FDG PET/CT than for 18F-FLT PET/CT. A common finding was a mismatch of focally increased 18F-FDG uptake and reduced 18F-FLT uptake (lower than the surrounding bone marrow). Moreover, 18F-FLT PET/CT was characterized by high background activity in the bone marrow compartment, further complicating the evaluation of bone marrow lesions. Semi-quantitative evaluation revealed that both SUVmean and SUVmax were significantly higher for 18F-FLT than for 18F-FDG in both MM lesions and reference tissue. SUV values were higher in MM lesions than in reference bone marrow for both tracers. CONCLUSIONS:Despite the limited number of patients analyzed in this pilot study, the first results of the trial indicate that 18F-FLT does not seem suitable as a single tracer in MM diagnostics. Further studies with a larger patient population are warranted to generalize the herein presented results.
Project description:The PET Response Criteria in Solid Tumors (PERCIST) are not specific regarding the number of lesions that should be analyzed per patient. This study evaluated how the number of analyzed lesions affects response assessment in metastatic breast cancer.In 60 patients, response was assessed by the change in SUVpeak, normalized to lean body mass, of the most (18)F-FDG-avid lesion (PERCIST 1) and by the change in the sum of normalized SUVpeak for up to 5 lesions (PERCIST 5). The correlation between response by PERCIST and progression-free and disease-specific survival was evaluated.In responders and nonresponders, the respective progression-free survival at 2 y was 37.26% and 6.43% for PERCIST 1 (P < 0.0001) and 33.65% and 7.14% for PERCIST 5 (P < 0.0001) and the respective disease-specific survival at 4 y was 58.96% and 25.44% for PERCIST 1 (P < 0.012) and 59.12% vs 20.01% for PERCIST 5 (P < 0.002).The number of analyzed lesions does not appear to have a major impact on the prognostic value of response assessment with (18)F-FDG PET/CT in metastatic breast cancer.
Project description:Response evaluation at regular intervals is indicated for treatment of metastatic breast cancer (MBC). FDG-PET/CT has the potential to monitor treatment response accurately. Our purpose was to: (a) compare the interrater agreement and reliability of the semi-quantitative PERCIST criteria to qualitative visual assessment in response evaluation of MBC and (b) investigate the intrarater agreement when comparing visual assessment of each rater to their respective PERCIST assessment. We performed a retrospective study on FDG-PET/CT in women who received treatment for MBC. Three specialists in nuclear medicine categorized response evaluation by qualitative assessment and standardized one-lesion PERCIST assessment. The scans were categorized into complete metabolic response, partial metabolic response, stable metabolic disease, and progressive metabolic disease. 37 patients with 179 scans were included. Visual assessment categorization yielded moderate agreement with an overall proportion of agreement (PoA) between raters of 0.52 (95% CI 0.44-0.66) and a Fleiss kappa estimate of 0.54 (95% CI 0.46-0.62). PERCIST response categorization yielded substantial agreement with an overall PoA of 0.65 (95% CI 0.57-0.73) and a Fleiss kappa estimate of 0.68 (95% CI 0.60-0.75). The difference in PoA between overall estimates for PERCIST and visual assessment was 0.13 (95% CI 0.06-0.21; <i>p</i> = 0.001), that of kappa was 0.14 (95% CI 0.06-0.21; <i>p</i> < 0.001). The overall intrarater PoA was 0.80 (95% CI 0.75-0.84) with substantial agreement by a Fleiss kappa of 0.74 (95% CI 0.69-0.79). Semi-quantitative PERCIST assessment achieved significantly higher level of overall agreement and reliability compared with qualitative assessment among three raters. The achieved high levels of intrarater agreement indicated no obvious conflicting elements between the two methods. PERCIST assessment may, therefore, give more consistent interpretations between raters when using FDG-PET/CT for response evaluation in MBC.
Project description:Radiation-induced changes may cause a non-malignant high 2-deoxy-2-[<sup>18</sup>F]fluoro-d-glucose (FDG)-uptake. The 3'-deoxy-3'-[<sup>18</sup>F]fluorothymidine (FLT)-PET/CT performs better in the differential diagnosis of inflammatory changes and lung lesions with a higher specificity than FDG-PET/CT. We investigated the association between post-radiotherapy FDG-PET-parameters, FLT-PET-parameters, and outcome. Sixty-one patients suspected for having a relapse after definitive radiotherapy for lung cancer were included. All the patients had FDG-PET/CT and FLT-PET/CT. FDG-PET- and FLT-PET-parameters were collected from within the irradiated high-dose volume (HDV) and from recurrent pulmonary lesions. For associations between PET-parameters and relapse status, respectively, the overall survival was analyzed. Thirty patients had a relapse, of these, 16 patients had a relapse within the HDV. FDG-SUV<sub>max</sub> and FLT-SUV<sub>max</sub> were higher in relapsed HDVs compared with non-relapsed HDVs (median FDG-SUV<sub>max</sub>: 12.8 vs. 4.2; <i>p</i> < 0.001; median FLT-SUV<sub>max</sub> 3.9 vs. 2.2; <i>p</i> < 0.001). A relapse within HDV had higher FDG-SUV<sub>peak</sub> (median FDG-SUV<sub>peak</sub>: 7.1 vs. 3.5; <i>p</i> = 0.014) and was larger (median metabolic tumor volume (MTV<sub>50%</sub>): 2.5 vs. 0.7; 0.014) than the relapsed lesions outside of HDV. The proliferative tumor volume (PTV<sub>50%</sub>) was prognostic for the overall survival (hazard ratio: 1.07 pr cm<sup>3</sup> [1.01-1.13]; <i>p</i> = 0.014) in the univariate analysis, but not in the multivariate analysis. FDG-SUV<sub>max</sub> and FLT-SUV<sub>max</sub> may be helpful tools for differentiating the relapse from radiation-induced changes, however, they should not be used definitively for relapse detection.
Project description:The use of 18-fluorodeoxyglucose (FDG) positron emission tomography with computed tomography (PET/CT) in subjects with advanced basal cell carcinoma (BCC) has not been fully explored due to the rarity of disease presentation. This study evaluated PET/CTs from subjects with advanced BCC participating in a phase I dose-escalation clinical trial of vismodegib. Fourteen subjects with BCC were imaged with 18-FDG PET/CT for lesion identification and response categorizing (European Organisation for Research and Treatment for Cancer [EORTC] and PET response criteria in solid tumors [PERCIST] 1.0). Several parameters including metabolic activity of target lesions, site of disease presentation and spread, treatment response, and prognostic significance of metabolic activity following therapy were evaluated. All subjects exhibited at least one hypermetabolic lesion. Most subjects had only four organ systems involved at study enrollment: skin-muscle (93%), lung (57%), lymph nodes (29%), and bone (21%). SUVmax measured across all lesions decreased (median 33%, SD ± 45%) following therapy with metabolic activity normalizing or disappearing in 42% of lesions. No significant difference was observed between EORTC and PERCIST 1.0. Subjects that demonstrated at least a 33% reduction in SUVmax from baseline had a significantly longer progression-free survival (PFS) (median 17 months, 95% confidence interval [CI] ±4 months vs. 9 months, 95% CI ±5 months, P = 0.038) and overall survival (OS) (median 24 months, 95% CI ±4 months vs. 17 months, 95% CI ±13 months, P = 0.019). BCC lesions are hypermetabolic on 18-FDG PET/CT. A decrease in SUVmax was associated with improved PFS and OS. These results further support the incorporation of 18-FDG PET/CT scans in advanced BCC management.