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11C-acetate PET/CT before radical prostatectomy: nodal staging and treatment failure prediction.

ABSTRACT: Despite early detection programs, many patients with prostate cancer present with intermediate- or high-risk disease. We prospectively investigated whether (11)C-acetate PET/CT predicts lymph node (LN) metastasis and treatment failure in men for whom radical prostatectomy is planned.107 men with intermediate- or high-risk localized prostate cancer and negative conventional imaging findings underwent PET/CT with (11)C-acetate. Five underwent LN staging only, and 102 underwent LN staging and prostatectomy. PET/CT findings were correlated with pathologic nodal status. Treatment-failure-free survival was estimated by the Kaplan-Meier method. The ability of PET/CT to predict outcomes was evaluated by multivariate Cox proportional hazards analysis.PET/CT was positive for pelvic LN or distant metastasis in 36 of 107 patients (33.6%). LN metastasis was present histopathologically in 25 (23.4%). The sensitivity, specificity, and positive and negative predictive values of PET/CT for detecting LN metastasis were 68.0%, 78.1%, 48.6%, and 88.9%, respectively. Treatment failed in 64 patients: 25 with metastasis, 17 with a persistent postprostatectomy prostate-specific antigen level greater than 0.20 ng/mL, and 22 with biochemical recurrence (prostate-specific antigen level > 0.20 ng/mL after nadir) during follow-up for a median of 44.0 mo. Treatment-failure-free survival was worse in PET-positive than in PET-negative patients (P < 0.0001) and in those with false-positive than in those with true-negative scan results (P < 0.01), suggesting that PET may have demonstrated nodal disease not removed surgically or identified pathologically. PET positivity independently predicted failure in preoperative (hazard ratio, 3.26; P < 0.0001) and postoperative (hazard ratio, 3.07; P = 0.0001) multivariate models.In patients planned for or completing prostatectomy, (11)C-acetate PET/CT detects LN metastasis not identified by conventional imaging and independently predicts treatment-failure-free survival.

SUBMITTER: Haseebuddin M

PROVIDER: S-EPMC3787881 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature

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11C-acetate PET/CT before radical prostatectomy: nodal staging and treatment failure prediction.

Haseebuddin Mohammed M Dehdashti Farrokh F Siegel Barry A BA Liu Jingxia J Roth Elizabeth B EB Nepple Kenneth G KG Siegel Cary L CL Fischer Keith C KC Kibel Adam S AS Andriole Gerald L GL Miller Tom R TR

Journal of nuclear medicine : official publication, Society of Nuclear Medicine 20130307 5

<h4>Unlabelled</h4>Despite early detection programs, many patients with prostate cancer present with intermediate- or high-risk disease. We prospectively investigated whether (11)C-acetate PET/CT predicts lymph node (LN) metastasis and treatment failure in men for whom radical prostatectomy is planned.<h4>Methods</h4>107 men with intermediate- or high-risk localized prostate cancer and negative conventional imaging findings underwent PET/CT with (11)C-acetate. Five underwent LN staging only, and ...[more]

PMID: 23471311

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Project description:INTRODUCTION:11C-acetate (ACE)-PET/CT is used for staging of high-risk prostate cancer. PET data is reconstructed with iterative algorithms, such as VUEPointHD ViP (VPHD) and VUEPoint HD Sharp IR (SharpIR), the latter with additional resolution recovery. It is expected that the resolution recovery algorithm should render more accurate maximum and mean standardized uptake values (SUVmax and SUVmean) and functional tumor volumes (FTV) than the ordinary OSEM. Performing quantitative analysis, choice of volume-of-interest delineation algorithm (SUV threshold) may influence FTV. Optimizing PET acquisition time is justified if image quality and quantitation do not deteriorate. The aim of this study is to identify the optimal reconstruction algorithm, SUV threshold and acquisition time for ACE-PET/CT. METHODS:ACE-PET/CT data acquired with a General Electric Discovery 690 PET/CT from 16 consecutive high-risk prostate cancer patients was reconstructed with VPHD and SharpIR. Forty pelvic lymph nodes (LNs) and 14 prostate glands were delineated with 42% and estimated threshold. SUVmax, SUVmean, FTV and total lesion uptake were measured. Default acquisition time was four minutes per bed position. In a subset of lesions, acquisition times of one, two and four minutes were evaluated. Structural tumor volumes (STV) of the LNs were measured with CT for correlation with functional volumetric parameters. To validate SUV quantification under different conditions with SharpIR 42%, recovery coefficients (RCs) of SUVmean and FTV were calculated from a phantom with 18F-fluoro-deoxy-glucose (FDG)-filled volumes 0.1-9.2cm3 and signal-to-background (S/B) ratios 4.3-15.9. RESULTS:With SharpIR, SUVmax and SUVmean were higher and FTV lower compared with VPHD, regardless of threshold method, in both prostates and LNs. Total lesion uptake determined with both threshold methods was lower with SharpIR compared with VPHD with both threshold methods, except in subgroup analysis of prostate targets where estimated threshold returned higher values. Longer acquisition times returned higher FTV for both threshold methods, regardless of reconstruction algorithm. The FTV difference was most pronounced with one minute's acquisition per bed position, which also produced visually the highest noise. SUV parameters were unaffected by varying acquisition times. FTV with SharpIR 42% showed the best correspondence with STV. SharpIR 42% gave higher RCs of SUVmean and FTV with increasing phantom size and S/B-ratio, as expected. CONCLUSIONS:Delineation with SharpIR 42% seems to provide the most accurate combined information from SUVmax, SUVmean, FTV and total lesion uptake. Acquisition time may be shortened to two minutes per bed position with preserved image quality.

Project description:UNLABELLED:This work characterizes the uptake of (11)C-acetate in prostate cancer (PCa), benign prostate hyperplasia, and normal prostate tissue in comparison with multiparametric MRI, whole-mount histopathology, and clinical markers to evaluate the potential utility of (11)C-acetate for delineating intraprostatic tumors in a population of patients with localized PCa. METHODS:Thirty-nine men with presumed localized PCa underwent dynamic-static abdominal-pelvic (11)C-acetate PET/CT for 30 min and 3-T multiparametric MRI before prostatectomy. PET/CT images were registered to MR images using pelvic bones for initial rotation-translation, followed by manual adjustments to account for prostate motion and deformation from the MRI endorectal coil. Whole-mount pathology specimens were sectioned using an MRI-based patient-specific mold resulting in improved registration between the MRI, PET, and pathology. (11)C-acetate PET standardized uptake values were compared with multiparametric MRI and pathology. RESULTS:(11)C-acetate uptake was rapid but reversible, peaking at 3-5 min after injection and reaching a relative plateau at approximately 10 min. The average maximum standardized uptake value (10-12 min) of tumors was significantly higher than that of normal prostate tissue (4.4 ± 2.05 [range, 1.8-9.2] vs. 2.1 ± 0.94 [range, 0.7-3.4], respectively; P < 0.001); however, it was not significantly different from that of benign prostatic hyperplasia (4.8 ± 2.01 [range, 1.8-8.8]). A sector-based comparison with histopathology, including all tumors greater than 0.5 cm, revealed a sensitivity and specificity of 61.6% and 80.0%, respectively, for (11)C-acetate PET/CT and 82.3% and 95.1%, respectively, for MRI. The (11)C-acetate accuracy was comparable to that of MRI when only tumors greater than 0.9 cm were considered. In a small cohort (n = 9), (11)C-acetate uptake was independent of fatty acid synthase expression using immunohistochemistry. CONCLUSION:(11)C-acetate PET/CT demonstrates higher uptake in tumor foci than in normal prostate tissue; however, (11)C-acetate uptake in tumors is similar to that in benign prostate hyperplasia nodules. Although (11)C-acetate PET/CT is not likely to have utility as an independent modality for evaluation of localized PCa, the high uptake in tumors may make it useful for monitoring focal therapy when tissue damage after therapy may limit anatomic imaging methods.

Project description:ObjectivesTo develop and validate a PET/CT nomogram for preoperative estimation of lymph node (LN) staging in patients with non-small cell lung cancer (NSCLC).MethodsA total of 263 pathologically confirmed LNs from 124 patients with NCSLC were retrospectively analyzed. Positron-emission tomography/computed tomography (PET/CT) examination was performed before treatment according to the clinical schedule. In the training cohort (N = 185), malignancy-related features, such as SUVmax, short-axis diameter (SAD), and CT radiomics features, were extracted from the regions of LN based on the PET/CT scan. The Minimum-Redundancy Maximum-Relevance (mRMR) algorithm and the Least Absolute Shrinkage and Selection Operator (LASSO) regression model were used for feature selection and radiomics score building. The radiomics score (Rad-Score) and SUVmax were incorporated in a PET/CT nomogram using the multivariable logistic regression analysis. The performance of the proposed model was evaluated with discrimination, calibration, and clinical application in an independent testing cohort (N = 78).ResultsThe radiomics scores consisting of 14 selected features were significantly associated with LN status for both training cohort with AUC of 0.849 (95% confidence interval (CI), 0.796-0.903) and testing cohort with AUC of 0.828 (95% CI, 0.782-0.919). The PET/CT nomogram incorporating radiomics score and SUVmax showed moderate improvement of the efficiency with AUC of 0.881 (95% CI, 0.834-0.928) in the training cohort and AUC of 0.872 (95% CI, 0.797-0.946) in the testing cohort. The decision curve analysis indicated that the PET/CT nomogram was clinically useful.ConclusionThe PET/CT nomogram, which incorporates Rad-Score and SUVmax, can improve the diagnostic performance of LN metastasis.Key points• The PET/CT nomogram (Int-Score) based on lymph node (LN) PET/CT images can reliably predict LN status in NSCLC. • Int-Score is a relatively objective diagnostic method, which can play an auxiliary role in the process of clinicians making treatment decisions.

Project description:Combined whole-body dual-tracer ((18)F-FDG and (11)C-acetate) PET/CT is increasingly used for staging hepatocellular carcinoma, with only limited studies investigating the radiation dosimetry data of these scans. The aim of the study was to characterize the radiation dosimetry of combined whole-body dual-tracer PET/CT protocols.Consecutive adult patients with hepatocellular carcinoma who underwent whole-body dual-tracer PET/CT scans were retrospectively reviewed with institutional review board approval. OLINDA/EXM 1.1 was used to estimate patient-specific internal dose exposure in each organ. Biokinetic models for (18)F-FDG and (11)C-acetate as provided by ICRP (International Commission on Radiological Protection) publication 106 were used. Standard reference phantoms were modified to more closely represent patient-specific organ mass. With patient-specific parameters, organ equivalent doses from each CT series were estimated using VirtualDose. Dosimetry capabilities for tube current modulation protocols were applied by integrating with the latest anatomic realistic models. Effective dose was calculated using ICRP publication 103 tissue-weighting coefficients for adult male and female, respectively.Fourteen scans were evaluated (12 men, 2 women; mean age ± SD, 60 ± 19.48 y). The patient-specific effective dose from (18)F-FDG and (11)C-acetate was 6.08 ± 1.49 and 1.56 ± 0.47 mSv, respectively, for male patients and 6.62 ± 1.38 and 1.79 ± 0.12 mSV, respectively, for female patients. The patient-specific effective dose of the CT component, which comprised 2 noncontrast whole-body scans, to male and female patients was 21.20 ± 8.94 and 14.79 ± 3.35 mSv, respectively. Thus, the total effective doses of the combined whole-body dual-tracer PET/CT studies for male and female patients were 28.84 ± 10.18 and 23.19 ± 4.61 mSv, respectively.Patient-specific parameters allow for more accurate estimation of organ equivalent doses. Considering the substantial radiation dose incurred, judicious medical justification is required with every whole-body dual-tracer PET/CT referral. Although radiation risks may have less impact for the population with cancer because of their reduced life expectancy, the information is of interest and relevant for both justification, to evaluate risk/benefit, and protocol optimization.

Dataset Information

11C-acetate PET/CT before radical prostatectomy: nodal staging and treatment failure prediction.

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11C-acetate PET/CT before radical prostatectomy: nodal staging and treatment failure prediction.

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