PET Response Criteria In Solid Tumors Criteria Research Articles

SDHx mutations and temozolomide in malignant pheochromocytoma and paraganglioma

Malignant pheochromocytomas (PHEOs)/paragangliomas (PGLs) are rare tumors for which clinical outcomes remain poorly defined and therapeutic options are limited. Approximately 27% carry pathogenic germline succinate dehydrogenase (SDHx) mutations; the presence of such mutations has been correlated with response to temozolomide (TMZ). We aimed to investigate the association between germline mutations in SDHx and response to TMZ. We retrospectively identified patients with metastatic malignant PHEO/PGLs treated with TMZ- based chemotherapy at Dana-Farber Cancer Institute between 2003 and 2020. The correlation between response by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and PET Response Criteria in Solid Tumors (PERCIST) and the presence of SDHx mutations in the germline and tumor was evaluated. Nineteen patients received TMZ. Seventeen underwent germline assessment: 9 (53%) carried a pathogenic SDHx germline mutation. Fifteen patients were evaluable for response by RECIST 1.1: 6 (40%) partial response, 4 (27%) stable disease, and 5 (33%) progressive disease. Overall median progression-free survival was 2.2 years. Three-year overall survival (OS) was 58%. Median PFS was 1.3 years and 5.5 years for carriers and non-carriers, respectively and OS was 1.5 years and not estimable for carriers and non-carriers, respectively. The response by PERCIST criteria in nine patients correlated with the RECIST 1.1 assessment. Our series represents one of the largest analyses of patients with malignant PHEOs/PGLs treated with TMZ who have available germline data. The incidence of pathogenic germline SDHx mutations was similar to what has been previously published, though our analysis suggests that there may be a limited association between response to TMZ and pathogenic germline SDHx mutations.

Evaluation of response to stereotactic body radiation therapy for nonsmall cell lung cancer: PET response criteria in solid tumors versus response evaluation criteria in solid tumors.

Recommendations for surveillance after stereotactic body radiation therapy (SBRT) for early-stage nonsmall cell lung cancer (NSCLC) are not well defined. Recently, PET response criteria in solid tumors (PERCIST) have been proposed as a new standardized method to assess radiotherapeutic response both quantitatively and metabolically. The aim of this study was to evaluate therapeutic response following SBRT in early-stage NSCLC patients by comparing PERCIST with the currently widely used RECIST. Forty-nine patients with early-stage NSCLC who had been prescribed SBRT were studied. Responses of lesion were evaluated using CT and 18F-FDG PET according to the RECIST and PERCIST methods. PET-CT scans were obtained before SBRT and 3-6 months after SBRT. Associations between overall survival (OS) and clinicopathologic results (histology, tumor location, tumor size, lymphatic invasion, clinical stage, and radiotherapeutic responses in RECIST and PERCIST) were statistically analyzed. The median patient follow-up was 30 months. Thirteen patients had stage IA, 9 stage IB, 10 stage IIA, and 17 stage IIB biopsy-proven NSCLC. Three-year OS was 79.6%. CT scans indicated three regional recurrences. PET-CT/chest indicated three regional recurrences and distant metastasis. Significant differences were observed in response classification between RECIST and PERCIST (Wilcoxon signed-rank test, P = 0.0041). Univariate analysis showed that clinical stage, RECIST, and PERCIST were significant factors associated with OS, whereas by multivariate analysis PERCIST was the only predictor of OS. SMD, PMD/PMR, and CMR in PERCIST criteria were indicative of a 9.900-fold increase in the risk of OS in early NSCLC patients [risk ratio, 9.900 (95% CI, 1.040-21.591); P = 0.001]. RECIST based on the anatomic size reduction rate did not demonstrate the correlation between radiotherapeutic response and prognosis in patients with early-stage NSCLC receiving SBRT. However, PERCIST was shown as the strongest independent predictor of outcomes. PERCIST might be considered more suitable for the evaluation of NSCLC tumor response to SBRT than RECIST.

18F-Fluorodeoxyglucose PET/CT for Early Prediction of Outcomes in Patients with Advanced Lung Adenocarcinomas and EGFR Mutations Treated with First-Line EGFR-TKIs.

Simple SummaryEpithelial growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are the first-line therapy for patients with advanced-stage lung adenocarcinoma with EGFR mutations. However, 17–31% of these patients do not respond to therapy, making early evaluation of treatment response crucial. This prospective study investigates the value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for timely prediction of response and survival of these patients. We evaluated 30 patients with stage IIIB/IV lung adenocarcinomas and EGFR mutations, receiving first-line EGFR-TKI therapy. 18F-FDG PET/CT was performed before and two weeks after initiation of treatment. Positron Emission Tomography Response Criteria in Solid Tumors served as an independent predictor of non-progressive disease; baseline and change of metabolic tumor volume represented independent predictors of progression-free survival and overall survival, respectively. Therefore, 18F-FDG PET/CT is an early predictor of outcomes and individual prognosis of patients with stage IIIB/IV lung adenocarcinomas and EGFR mutations receiving first-line EGFR-TKI therapy.This study aims to investigate the role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in early prediction of response and survival following epithelial growth factor receptor (EGFR)–tyrosine kinase inhibitor (TKI) therapy in patients with advanced lung adenocarcinomas and EGFR mutations. Thirty patients with stage IIIB/IV lung adenocarcinomas and EGFR mutations receiving first-line EGFR-TKIs were prospectively evaluated between November 2012 and May 2015. EGFR mutations were quantified by delta cycle threshold (dCt). 18F-FDG PET/CT was performed before and 2 weeks after treatment initiation. PET response was assessed based on PET Response Criteria in Solid Tumors (PERCIST). Baseline and percentage changes in the summed standardized uptake value, metabolic tumor volume (bsumMTV and ΔsumMTV, respectively), and total lesion glycolysis of ≤5 target lesions/patient were calculated. The association between parameters (clinical and PET) and non-progression disease after 3 months of treatment in CT based on the Response Evaluation Criteria in Solid Tumors Version 1.1 (nPD3mo), progression-free survival (PFS), and overall survival (OS) were tested. The median follow-up time was 19.6 months. The median PFS and OS were 12.0 and 25.3 months, respectively. The PERCIST criteria was an independent predictor of nPD3mo (p = 0.009), dCt (p = 0.014) and bsumMTV (p = 0.014) were independent predictors of PFS, and dCt (p = 0.014) and ΔsumMTV (p = 0.005) were independent predictors of OS. 18F-FDG PET/CT achieved early prediction of outcomes in patients with advanced lung adenocarcinomas and EGFR mutations receiving EGFR-TKIs.

Bronchial or Pulmonary Artery Chemoembolization for Unresectable and Unablatable Lung Metastases.

HomeRadiology: Imaging CancerVol. 3, No. 6 PreviousNext Research HighlightsFree AccessBronchial or Pulmonary Artery Chemoembolization for Unresectable and Unablatable Lung MetastasesMaximiliano KlugMaximiliano KlugMaximiliano KlugPublished Online:Nov 26 2021https://doi.org/10.1148/rycan.2021219023MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Take-Away Points■ Major Focus: A phase I clinical trial study prospectively evaluated the success rate and safety of transarterial chemoembolization (TACE) of bronchial or pulmonary arteries using ethiodized oil, mitomycin, and microspheres for treatment of unresectable and unablatable lung metastases.■ Key Results: Technical efficacy was 100% with no immediate major adverse events reported. Forty percent of patients showed partial metabolic response according to the PET Response Criteria in Solid Tumors (PERCIST).■ Impact: Lung TACE is a safe and technically achievable procedure with promising results for large and multifocal lung metastases with limited treatment options. Larger multicenter randomized clinical trials are needed to further evaluate safety and efficacy.Prognosis is poor for unresectable and unablatable lung metastases when they stop responding to systemic chemotherapy. Lung TACE of the pulmonary or bronchial arteries is an emerging treatment option for large and multifocal lung tumors, although response rate remains low. The authors hypothesize that the potential dual blood supply of lung tumors from bronchial or pulmonary arteries limits success of TACE.The single-center study prospectively enrolled patients with unresectable and unablatable lung, endobronchial, mediastinal, or pleural metastases from any primary tumor except lung cancer for which systemic chemotherapy failed. Nine of 10 patients had metastatic colorectal cancer. On the basis of pretreatment pulmonary and bronchial angiography, the authors performed chemoembolization with ethiodized oil, mitomycin, and microspheres through the artery that showed greater perfusion tumor enhancement at angiography. The study defined technical success by delivery of ethiodized oil and mitomycin into an artery supplying a target tumor, with safety assessment ending 6 weeks after the procedure. Using untreated tumors in a patient as an internal control, the team measured response to therapy by PERCIST and Response Evaluation Criteria in Solid Tumors (RECIST).The study reports that the technical success of intratumoral drug delivery was 100% with no severe adverse effects. However, both forced vital capacity and forced expiratory volume in 1 second decreased persistently through 4–6 weeks. Partial response rates after 4–6 weeks were 40% and 10% by PERCIST and RECIST, respectively. All colorectal metastases had bronchial artery supply, and tumor response by PERCIST correlated with concentration of ethiodized oil in a tumor.Although limited by small numbers of patients, the demonstrated efficacy and safety obtained and preliminary partial response rates encourage future larger clinical trials. Correctly identifying the vascular anatomy of lung metastases in unresectable and unablatable disease may be key for future improvements in TACE for lung metastases.Highlighted ArticleBoas FE, Kemeny NE, Sofocleous CT, et al. Bronchial or pulmonary artery chemoembolization for unresectable and unablatable lung metastases: a phase I clinical trial. Radiology 2021;301(2):474–484. doi: https://doi.org/10.1148/radiol.2021210213Highlighted ArticleBoas FE, Kemeny NE, Sofocleous CT, et al. Bronchial or pulmonary artery chemoembolization for unresectable and unablatable lung metastases: a phase I clinical trial. Radiology 2021;301(2):474–484. doi: https://doi.org/10.1148/radiol.2021210213 Link, Google ScholarArticle HistoryPublished online: Nov 26 2021 FiguresReferencesRelatedDetailsRecommended Articles Bronchial or Pulmonary Artery Chemoembolization for Unresectable and Unablatable Lung Metastases: A Phase I Clinical TrialRadiology2021Volume: 301Issue: 2pp. 474-484Chemoembolization for Lung Neoplasms: Exuberant Expectations versus Meticulous InvestigationRadiology2021Volume: 301Issue: 2pp. 485-486Survival and Toxicities after 90Y Transarterial Radioembolization of Metastatic Colorectal Cancer in the RESIN RegistryRadiology2022Volume: 305Issue: 1pp. 228-236Imaging Biomarkers of Tumor Response in Neuroendocrine Liver Metastases Treated with Transarterial Chemoembolization: Can Enhancing Tumor Burden of the Whole Liver Help Predict Patient Survival?Radiology2016Volume: 283Issue: 3pp. 883-894Prediction of Therapeutic Effect of Chemotherapy for NSCLC Using Dual-Input Perfusion CT Analysis: Comparison among Bevacizumab Treatment, Two-Agent Platinum-based Therapy without Bevacizumab, and Other Non-Bevacizumab Treatment GroupsRadiology2017Volume: 286Issue: 2pp. 685-695See More RSNA Education Exhibits Review of Different Underlying Causes of Life-Threatening HemoptysisDigital Posters2018Comprehensive Review of Hemoptysis: Imaging and TreatmentDigital Posters2018Hemoptysis: A Practical Guide to Understand Its Causes and TreatmentsDigital Posters2019 RSNA Case Collection Rasmussen aneurysmRSNA Case Collection2022Pulmonary pseudoaneurysmRSNA Case Collection2021Radioembolization of Liver Metastasis RSNA Case Collection2020 Vol. 3, No. 6 Metrics Altmetric Score PDF download

Tumor response evaluation in patients with malignant melanoma undergoing immune checkpoint inhibitor therapy and prognosis prediction using 18F-FDG PET/CT: multicenter study for comparison of EORTC, PERCIST, and imPERCIST

ObjectiveIn malignant melanoma patients treated with immune checkpoint inhibitor (ICI) therapy, three different FDG-PET criteria, European Organization for Research and Treatment of Cancer (EORTC), PET Response Criteria in Solid Tumors (PERCIST), immunotherapy-modified PERCIST (imPERCIST), were compared regarding response evaluation and prognosis prediction using standardized uptake value (SUV) harmonization of results obtained with various PET/CT scanners installed at different centers.Materials and methodsMalignant melanoma patients (n = 27) underwent FDG-PET/CT examinations before and again 3 to 9 months after therapy initiation (nivolumab, n = 21; pembrolizumab, n = 6) with different PET scanners at five hospitals. EORTC, PERCIST, and imPERCIST criteria were used to evaluate therapeutic response, then concordance of the results was assessed using Cohen’s κ coefficient. Log-rank and Cox methods were employed to determine progression-free (PFS) and overall (OS) survival.ResultsComplete metabolic response (CMR)/partial metabolic response (PMR)/stable metabolic disease (SMD)/progressive metabolic disease (PMD) with harmonized EORTC, PERCIST, and imPERCIST was seen in 3/5/4/15, 4/5/3/15, and 4/5/5/13 patients, respectively. Nearly perfect concordance between each pair of criteria was noted (κ = 0.939–0.972). Twenty patients showed progression and 14 died from malignant melanoma after a median 19.2 months. Responders (CMR/PMR) showed significantly longer PFS and OS than non-responders (SMD/PMD) (harmonized EORTC: p < 0.0001 and p = 0.011; harmonized PERCIST: p < 0.0001 and p = 0.0012; harmonized imPERCIST: p < 0.0001 and p = 0.0012, respectively).ConclusionsAll harmonized FDG-PET criteria (EORTC, PERCIST, imPERCIST) showed accuracy for response evaluation of ICI therapy and prediction of malignant melanoma patient prognosis. Additional studies to determine their value in larger study populations will be necessary.

Role of Baseline and Post-Therapy 18F-FDG PET in the Prognostic Stratification of Metastatic Castration-Resistant Prostate Cancer (mCRPC) Patients Treated with Radium-223.

Radium-223 dichloride (Ra223) represents the unique bone-directed treatment option that shows an improvement in overall survival (OS) in metastatic castrate resistant prostate cancer (mCRPC). However, there is an urgent need for the identification of reliable biomarkers to non-invasively determine its efficacy (possibly improving patients’ selection or identifying responders’ after therapy completion). 18F-Fluorodeoxyglucose (FDG)-avidity is low in naïve prostate cancer, but it is enhanced in advanced and chemotherapy-refractory mCRPC, providing prognostic insights. Moreover, this tool showed high potential for the evaluation of response in cancer patients with bone involvement. For these reasons, FDG Positron Emission Tomography (FDG-PET) might represent an effective tool that is able to provide prognostic stratification (improving patients selection) at baseline and assessing the treatment response to Ra223. We conducted a retrospective analysis of 28 mCRPC patients that were treated with Ra223 and submitted to bone scan and FDG-PET/CT for prognostic purposes at baseline and within two months after therapy completion. The following parameters were measured: number of bone lesions at bone scan, SUVmax of the hottest bone lesion, metabolic tumor volume (MTV), and total lesion glycolysis (TLG). In patients who underwent post-therapy 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT), (20/28), PET Response Criteria in Solid Tumors (PERCIST), and European Organization for Research and Treatment of Cancer (EORTC) criteria were applied to evaluate the metabolic treatment response. The difference between end of therapy and baseline values was also calculated for Metabolic Tumor Volume (MTV), TLG, prostate-specific antigen (PSA), alkaline phosphatase (AP), and lactate dehydrogenase (LDH) (termed deltaMTV, deltaTLG, deltaPSA, deltaAP and deltaLDH, respectively). Predictive power of baseline and post-therapy PET- and biochemical-derived parameters on OS were assessed by Kaplan–Meier, univariate and multivariate analyses. At baseline, PSA, LDH, and MTV significantly predicted OS. However, MTV (but not PSA nor LDH) was able to identify a subgroup of patients with worse prognosis, even after adjusting for the number of lesions at bone scan (which, in turn, was not an independent predictor of OS). After therapy, PERCIST criteria were able to capture the response to Ra223 by demonstrating longer OS in patients with partial metabolic response. Moreover, the biochemical parameters were outperformed by PERCIST in the post-treatment setting, as their variation after therapy was not informative on long term OS. The present study supports the role of FDG-PET as a tool for patient’s selection and response assessment in mCRPC patients undergoing Ra223 administration.

Agreement Between the European Organization for Research and Treatment of Cancer and Positron Emission Tomography Response Criteria in Solid Tumors in Evaluating Treatment Response in Solid Malignant Tumors.

IntroductionFluorine-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) is used for non-invasive staging and restaging of solid malignant tumors. PET-CT based criteria have been developed to evaluate the response to targeted therapy. These include the European Organization for Research and Treatment of Cancer (EORTC) and the PET Response Criteria in Solid Tumors (PERCIST). The aim of this study was to determine the agreement between EORTC and PERCIST criteria for treatment response evaluation in patients with solid malignant tumors.Materials and methodsThis was a retrospective study conducted from February 2017 till July 2017. Electronic medical records of patients diagnosed with solid malignant tumors were searched. Experienced radiologists evaluated the PET-CT images based on EORTC and PERCIST criteria. The Kappa (κ) test was used for evaluation of agreement between treatment response according to EORTC and PERCIST criteria.ResultsOut of 54 patients, 41 (75.9%) were male and 13 (24.1%) were female with a mean age of 57.09 ± 10.65 years. According to EORTC criteria, complete metabolic response (CMR) was seen in five (9.3%) of patients, partial metabolic response (PMR) was seen in 36 (66.7%) of patients, progressive metabolic disease (PMD) was seen in nine (16.7%) of patients and stable metabolic disease (SMD) was seen in four (7.4%) of patients. According to PERCIST criteria, CMR was seen in five (9.3%) of patients, PMR was seen in 33 (61.1%) of patients, PMD was seen in nine (16.7%) of patients and SMD was seen in seven (13.0%) of patients. EORTC and PERCIST agreed on 43 (79.6%) of the patients with κ-coefficient of 0.62 indicating good agreement (p-value of <0.001).ConclusionEORTC and PERCIST criteria have a good agreement in evaluating treatment response in solid malignant tumors. Therefore, adoption of EORTC or PERCIST in PET-CT reporting can standardize the evaluation of oncological treatment results.

Response assessment in non-small cell lung cancer immunotherapy: initial experiences in utilizing FDG PET/CT and the PD-1 blocker nivolumab

Most Non-Small-Cell lung cancer (NSCLC) patients need systemic treatment. Immunotherapy is now current standard in first- and second-line treatment. In all pivotal studies, staging was performed using conventional computer tomography (CT) scans. PET/CT-based treatment monitoring is on the contrary recommended in NSCLC guidelines. This investigation aims at describing the benefits, challenges and possible pitfalls of using PET/CT-based monitoring for lung cancer during immunotherapy. We analyzed 11 NSCLC patients treated with nivolumab at a German tertiary care lung cancer center between 2015 and 2016. All patients received at least two follow-up PET-CTs. Evaluation of response was based on both Response Evaluation Criteria in Solid Tumors (RECIST) and PET Response Criteria in Solid Tumors (PERCIST) criteria. In 7 out of 11 cases, the RECIST and PERCIST results concurred, but two patients with initial stable disease regarding RECIST were reclassified as progressive metabolic disease based on PERCIST criteria. Additionally we identified one case of pseudoprogression using PERCIST criteria in contrast to stable disease using RECIST criteria and one case showing an early and durable response to nivolumab treatment using RECIST, despite a highly hypermetabolic mediastinal lymph node metastasis. The findings indicate that the PERCIST-based evaluation could identify progressive disease earlier. Early identification of nonresponders could lead to prevention of overtreatment and to an early switch to a more effective therapy.

Clinical Value of 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Response Evaluation after Primary Treatment of Advanced Epithelial Ovarian Cancer

AimsTo prospectively evaluate the use of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in the definition of the treatment response after primary treatment of advanced epithelial ovarian cancer (EOC). Materials and methodsForty-nine patients with advanced EOC had an 18F-FDG PET/CT scan before and after primary treatment. The treatment response was defined with the currently used radiological and serological Response Criteria in Solid Tumors (RECIST1.1/GCIC) criteria and the modified PET Response Criteria in Solid Tumors (PERCIST). The concordance of the two methods was analysed. If the patient had a complete response to primary treatment by conventional criteria, the end of treatment 18F-FDG PET/CT scan (etPET/CT) was not opened until retrospectively at the time of disease progression. The ability of etPET/CT to predict the time to disease recurrence was analysed. The recurrence patterns were observed with an 18F-FDG PET/CT at the first relapse. ResultsThe agreement of the RECIST1.1/GCIC and modified PERCIST criteria in defining the primary treatment response in the whole patient cohort was good (weighted kappa coefficient = 0.78). Of the complete responders (n = 28), 34% had metabolically active lesions present in the etPET/CT, most typically in the lymph nodes. The same anatomical sites tended to activate at disease relapse, but were seldom the only site of relapse. In patients with widespread intra-abdominal carsinosis at diagnosis, the definition of metabolic response was challenging due to problems in distinguishing the physiological FDG accumulation in the bowel loops from the residual tumour in the same area. The presence of metabolically active lesions in the etPET/CT did not predict earlier disease relapse in the complete responders. ConclusionsIn the present study, etPET/CT revealed metabolically active lesions in complete responders after EOC primary therapy, but they were insignificant for the patient's prognosis. The current study does not favour routine use of 18F-FDG PET/CT after EOC primary treatment for complete responders.

TLG-S criteria are superior to both EORTC and PERCIST for predicting outcomes in patients with metastatic lung adenocarcinoma treated with erlotinib

In this retrospective review of prospectively collected data, we sought to investigate whether early FDG-PET assessment of treatment response based on total lesion glycolysis measured using a systemic approach (TLG-S) would be superior to either local assessment with EORTC (European Organization for Research and Treatment of Cancer) criteria or single-lesion assessment with PERCIST (PET Response Criteria in Solid Tumors) for predicting clinical outcomes in patients with metastatic lung adenocarcinoma treated with erlotinib. We also examined the effect of bone flares on tumor response evaluation by single-lesion assessment with PERCIST in patients with metastatic bone lesions. We performed a retrospective review of prospectively collected data from 23 patients with metastatic lung adenocarcinoma treated with erlotinib. All participants underwent FDG-PET imaging at baseline and on days 14 and 56 after completion of erlotinib treatment. In addition, diagnostic CT scans were performed at baseline and on day 56. FDG-PET response was assessed with TLG-S, EORTC, and PERCIST criteria. Response assessment based on RECIST 1.1 (Response Evaluation Criteria in Solid Tumors) from diagnostic CT imaging was used as the reference standard. Two-year progression-free survival (PFS) and overall survival (OS) served as the main outcome measures. We identified 13 patients with bone metastases. Of these, four (31%) with persistent bone uptake due to bone flares on day 14 were erroneously classified as non-responders according to the PERCIST criteria, but they were correctly classified as responders according to both the EORTC and TLG-S criteria. Patients who were classified as responders on day 14 based on TLG-S criteria had higher rates of 2-year PFS (26.7% vs. 0%, P = 0.007) and OS (40.0% vs. 7.7%, P = 0.018). Similar rates were observed in patients who showed a response on day 56 based on CT imaging according to the RECIST criteria. Patients classified as responders on day 14 according to the EORTC criteria on FDG-PET imaging had better rates of 2-year OS than did non-responders (36.4% vs. 8.3%, P = 0.015). TLG-S criteria may be of greater help in predicting survival outcomes than other forms of assessment. Bone flares, which can interfere with the interpretation of treatment response based on PERCIST criteria, are not uncommon in patients with metastatic lung adenocarcinoma treated with erlotinib.

Usefulness of standardized uptake value normalized by individual CT-based lean body mass in application of PET response criteria in solid tumors (PERCIST).

Our aim in this study was to verify the usefulness of the standardized uptake value (SUV) normalized by individual CT-based lean body mass (LBMCT) in application of PET response criteria in solid tumors (PERCIST).We retrospectively investigated 14 patients (4 male and 10 female) with malignant lymphoma who were undergoing chemotherapy. (18)F-FDG PET/CT examinations were performed before and after chemotherapy. The LBMCT was calculated by estimation of fat weight from CT data (from skull base to pelvis). The mean±standard deviation (SD) and the Bland-Altman plot were used for comparison among body weight, LBMCT, and LBM derived from a predictive equation (LBMPE). Indices for FDG uptake in the liver were: SUV, SUV based on LBMPE (SULPE), and SUV based on LBMCT (SULCT). Overall differences between the uptake values were analyzed by one-way ANOVA. If the ANOVA showed significance, differences between uptake values were investigated further by use of the Tukey-Kramer test. The mean values of body weight, LBMPE, and LBMCT were: 55.4±14.9 (39.0-112.0), 43.0±10.5 (31.3-75.2), and 35.3±9.8 (23.4-75.8) kg, respectively. There was a wide dispersion between LBMPE and LBMCT (differences, 7.6±3.6kg; 95% CI, 6.42-8.85). LBMPE was higher than LBMCT in all the cases except in Case 11. The mean uptake values significantly differed among SUV, SULPE, and SULCT (F=68.3, p<0.05). Whereas SULPE deviated from PERCIST criteria in seven patients, SULCT satisfied the criteria except in one case. These results suggest that liver SULCT is useful for application of PERCIST.

PET/CT evaluation of response to chemotherapy in non-small cell lung cancer: PET response criteria in solid tumors (PERCIST) versus response evaluation criteria in solid tumors (RECIST).

(18)F-FDG PET/CT is increasingly used in evaluation of treatment response for patients with non-small cell lung cancer (NSCLC). There is a need for an accurate criterion to evaluate the effect and predict the prognosis. The aim of this study is to evaluate therapeutic response in NSCLC with comparing PET response criteria in solid tumors (PERCIST) to response evaluation criteria in solid tumors (RECIST) criteria on PET/CT. Forty-four NSCLC patients who received chemotherapy but no surgery were studied. Chemotherapeutic responses were evaluated using (18)F-FDG PET and CT according to the RECIST and PERCIST methodologies. PET/CT scans were obtained before chemotherapy and after 2 or 4-6 cycles' chemotherapy. The percentage changes of tumor longest diameters and standardized uptake value (SUV) (corrected for lean body mass, SUL) before and after treatment were compared using paired t-test. The response was categorized into 4 levels according to RECIST and PERCIST: CR (CMR) =1, PR (PMR) =2, SD (SMD) =3, PD (PMD) =4. Pearson chi-square test was used to compare the proportion of four levels in RECIST and PERCIST. Finally the relationship between progression-free survival (PFS) and clinicopathologic parameters (such as TNM staging, percentage changes in diameters and SUL, RECIST and PERCIST results etc.) were evaluated using univariate and multivariate Cox proportional hazards regression method. The difference of percentage changes between diameters and SUL was not significant using paired t-test (t=-1.69, P=0.098). However the difference was statistically significant in the 40 cases without increasing SUL (t=-3.31, P=0.002). The difference of evaluation results between RECIST and PERCIST was not significant by chi-square test (χ(2)=5.008, P=0.171). If RECIST evaluation excluded the new lesions which could not be found or identified on CT images the difference between RECIST and PERCIST was significant (χ(2)=11.759, P=0.007). Reduction rate of SULpeak (%), RECIST and PERCIST results were significant factors in univariate Cox analysis. But Multivariate Cox proportional hazards regression analysis demonstrated that only PERCIST was a significant factor for predicting DFS [hazard ratio (HR), 3.20; 95% (CI), 1.85-5.54; P<0.001]. PERCIST and RECIST criteria have good consistency and PERCIST (or PET) is more sensitive in detecting complete remission (CR) and progression. PERCIST might be the significant predictor of outcomes. The combination of PERCIST and RECIST would provide clinicians more accurate information of therapeutic response in earlier stage of treatment.

PERCIST criteria to predict survival at 3 months following intra-arterial resin-based yttrium-90 (Y-90) radioembolization therapy of unresectable intrahepatic cholangiocarcinoma refractory to standard chemotherapy: A proof of concept study.

e15141 Background: To investigate the prognostic value of PET Response Criteria in Solid Tumors (PERCIST) on predicting survival in patients with unresectable intrahepatic cholangiocarcinoma (ICC) after resin-basedYttrium-90 (Y-90) radioembolization. Methods: IRB approved prospective correlative study in ICC patients refractory to standard chemotherapy who had 18F-FDG PET-CT before and after Y-90 therapy. Measurable tumor was defined as a lesion ≥ 1 cm in diameter and maximum standardized uptake ((max) SUV) ≥ 2.5. (Max) SUV was measured in targeted and non-targeted lesions after local therapy (overall response). PERCIST criteria defined complete response (CR) as no FDG uptake within target lesion, and partial response (PR) as reduction of 30% in FDG (max) SUV peak in measurable lesions. Objective response included PR/CR. PET imaging was acquired pre-treatment, 1-3-and-6 months following Y90. Survival analyses were carried out with Kaplan–Meier and Log-Rank proportional models using SPSS software v20 (IBM, Armonk, NY) with significance set at &lt;0.05. Results: 9 consecutive patients were enrolled (56% men, mean age 58). Median overall survival from Y90 was 21.7 months. Average max SUV pretreatment was 10.02 and after Y90, 6.03. At 1-month after Y90, target PERCIST criteria showed CR= 1 (11.1%), PR=1 (11.1%), SD=7 (33.3%) and PD=0 (0.0%). Following 3-month after Y90, target response was CR= 2 (22.2%), PR=3 (33.3%), SD=3 (33.3%) and PD=1 (11.1%). No correlation between survival and either target or overall PERCIST criteria response on 1-month follow-up scan was seen(p=0.260). Statistically significant prolonged overall survival was observed for patients with objective targeted response based on PERCIST criteria at 3-month scan (P=0.022). In addition, objective overall PERCIST response at 3-month showed significant correlation with overall survival (p= 0.011). Conclusions: In patients with unresectable ICC refractory to standard chemotherapy, PERCIST criteria at 3-months following Y-90 therapy predict overall survival.

First report of the correlation of PET Response Criteria in Solid Tumors (PERCIST) criteria and pathologic change in patients with rectal cancer treated with neoadjuvant radiation.

261 Background: High-dose-rate endorectal brachytherapy (Endo-HDR) is a promising technique using a short course of radiation therapy in the neoadjuvant setting for rectal cancer. While clinical exam and standard imaging (CT and MRI) suggest outstanding radiation response in these patients, they cannot reliably predict pathologic complete response (pCR) or high tumor regression grade (TRG). In this study, we investigate the utility of PERCIST criteria to predict pathologic change. Methods: We treated nine patients on a prospective clinical trial investigating Endo-HDR as a single agent neoadjuvant therapy (6.5 Gy x 4 fractions, total dose of 26 Gy) for stage II-III rectal cancer patients. A pre-radiation PET/CT scan was compared to a post-treatment PET/CT scan performed one month following the completion of radiation. All nine patients proceeded to surgical resection with the pathologic specimen analyzed for residual disease. TRG (Mandard et al.) was used to quantify response to treatment. A 50% decrease in SUVpeak by PERCIST criteria was correlated with a TRG 1 or 2 (none or minimal residual cancer cells on the final pathologic specimen). Results: As demonstrated in our table, 3/5 (60%) of patients achieving a TRG 1 or 2 had a SUVpeak that decreased by 50% or more; contrarily, zero of 4 (0%) of patients without a TRG 1 or 2 had a SUVpeak of 50% or more. Despite a trend, the small patient sample limited statistical significance (p=0.17). A minimum decrease of 50% in SUVpeak resulted in a positive predictive value of 100%, a negative predictive value of 67%, a specificity of 100%, and a sensitivity of 60% for predicting TRG 1 or 2. Conclusions: Our results demonstrate the first report of utilizing PERCIST criteria in rectal cancer treated with neoadjuvant Endo-HDR. Reliable clinical predictors following Endo-HDR for excellent pathologic response may identify patients in whom a non-operative rectal cancer treatment is possible. [Table: see text]

From RECIST to PERCIST: Evolving Considerations for PET Response Criteria in Solid Tumors

The purpose of this article is to review the status and limitations of anatomic tumor response metrics including the World Health Organization (WHO) criteria, the Response Evaluation Criteria in Solid Tumors (RECIST), and RECIST 1.1. This article also reviews qualitative and quantitative approaches to metabolic tumor response assessment with (18)F-FDG PET and proposes a draft framework for PET Response Criteria in Solid Tumors (PERCIST), version 1.0. PubMed searches, including searches for the terms RECIST, positron, WHO, FDG, cancer (including specific types), treatment response, region of interest, and derivative references, were performed. Abstracts and articles judged most relevant to the goals of this report were reviewed with emphasis on limitations and strengths of the anatomic and PET approaches to treatment response assessment. On the basis of these data and the authors' experience, draft criteria were formulated for PET tumor response to treatment. Approximately 3,000 potentially relevant references were screened. Anatomic imaging alone using standard WHO, RECIST, and RECIST 1.1 criteria is widely applied but still has limitations in response assessments. For example, despite effective treatment, changes in tumor size can be minimal in tumors such as lymphomas, sarcoma, hepatomas, mesothelioma, and gastrointestinal stromal tumor. CT tumor density, contrast enhancement, or MRI characteristics appear more informative than size but are not yet routinely applied. RECIST criteria may show progression of tumor more slowly than WHO criteria. RECIST 1.1 criteria (assessing a maximum of 5 tumor foci, vs. 10 in RECIST) result in a higher complete response rate than the original RECIST criteria, at least in lymph nodes. Variability appears greater in assessing progression than in assessing response. Qualitative and quantitative approaches to (18)F-FDG PET response assessment have been applied and require a consistent PET methodology to allow quantitative assessments. Statistically significant changes in tumor standardized uptake value (SUV) occur in careful test-retest studies of high-SUV tumors, with a change of 20% in SUV of a region 1 cm or larger in diameter; however, medically relevant beneficial changes are often associated with a 30% or greater decline. The more extensive the therapy, the greater the decline in SUV with most effective treatments. Important components of the proposed PERCIST criteria include assessing normal reference tissue values in a 3-cm-diameter region of interest in the liver, using a consistent PET protocol, using a fixed small region of interest about 1 cm(3) in volume (1.2-cm diameter) in the most active region of metabolically active tumors to minimize statistical variability, assessing tumor size, treating SUV lean measurements in the 1 (up to 5 optional) most metabolically active tumor focus as a continuous variable, requiring a 30% decline in SUV for "response," and deferring to RECIST 1.1 in cases that do not have (18)F-FDG avidity or are technically unsuitable. Criteria to define progression of tumor-absent new lesions are uncertain but are proposed. Anatomic imaging alone using standard WHO, RECIST, and RECIST 1.1 criteria have limitations, particularly in assessing the activity of newer cancer therapies that stabilize disease, whereas (18)F-FDG PET appears particularly valuable in such cases. The proposed PERCIST 1.0 criteria should serve as a starting point for use in clinical trials and in structured quantitative clinical reporting. Undoubtedly, subsequent revisions and enhancements will be required as validation studies are undertaken in varying diseases and treatments.