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We studied diagnosis accuracy of 18 FDG-PET Computed Tomography (CT) in nodal staging of muscle invasive bladder cancer (MIBC) and the rate of treatment modification according to FDG-PET CT results. FDG-PET CT was more sensitive compared to CT alone for lymph node (LN) staging. Treatment decision were modified for 26% of patient due to FDG-PET CT findings. Introduction: Guidelines do not recommend FDG-PET CT for the staging of MIBC as a standard. The objectives of the study are to assess the accuracy of the FDG-PET CT for LN staging and to determine the rate of treatment modification according to FDG-PET CT results in MIBC. Patients and methods: From January 2005 to December 2017, we carried out a retrospective analysis of patients with MIBC who had a FDG-PET CT for staging in two expert centres in Bordeaux, France, and analyzed its clinical value in this setting. Nodal and metastatic staging on CT scan (CT) and FDG-PET CT were done independently. Results: Accuracy of LN staging from CT and FDG-PET CT at initial diagnosis was analyzed in 85 patients (including 70 patients treated with neoadjuvant chemotherapy (NAC)) and compared to pathological examination of resected LN. Sensitivity of FDG-PET CT was better than CT (80.8% versus 26.9%) but the specificity was low (54.2% vs. 83.1%). The Youden index was better for FDG-PET CT (0.35; 0.1 for CT) and FDG-PET CT appeared to be more accurate for determining LN staging of MIBC. FDG-PET CT findings enabled a treatment decision modification in 34/130 patients (26.1%): a therapeutic intensification (9.2%), including surgery not previously planned and/or modified fields of radiotherapy; or a de-escalation (16.9%), mostly avoiding surgery. Conclusion: FDG-PET CT was more sensitive for detection of LN involvement at initial diagnosis of MIBC than CT alone. In our study, treatment decisions were modified, according to FDG-PET CT results, in almost a quarter of patients. [ABSTRACT FROM AUTHOR]

Résumé: La radioembolisation des métastases hépatiques de cancer colorectal, ou radiothérapie interne sélective, est une technique qui consiste à délivrer par l'artère hépatique des microsphères chargées d'yttrium-90 radioactif, directement au sein des métastases hépatiques. L'effet thérapeutique de la radioembolisation est lié à la radiothérapie interne et non à l'embolisation. Elle nécessite plusieurs étapes rigoureuses, faisant intervenir des radiologues interventionnels, des médecins nucléaires, des radiopharmaciens et des radiophysiciens : une étape de simulation aux macroaggrégats d'albumine humaine, la dosimétrie, et la phase de traitement. La radio-embolisation est disponible en France depuis une dizaine d'années. Elle a été validée chez les patients ayant des métastases hépatiques exclusives réfractaires aux traitements systémiques, dans quelques études de faibles effectifs, permettant son remboursement par l'assurance maladie dans cette indication. De récentes grandes études de phase III ont évalué cette technique associée à la chimiothérapie, dès la première et deuxième ligne. En dépit d'une activité antitumorale évidente, permettant une amélioration du contrôle local, ces études n'ont en revanche pas permis de montrer un bénéfice en survie globale. Une amélioration des techniques de dosimétrie, une meilleure sélection des patients et des combinaisons avec des traitements susceptibles d'apporter des effets biologiques synergiques pourraient à l'avenir faire reconsidérer la place de la radioembolisation dans les lignes précoces de traitement. Radioembolization of colorectal cancer liver metastases, or selective internal radiation therapy, is a technique that consists of delivering radioactive yttrium-loaded microbeads through the hepatic artery directly into the liver metastases. The therapeutic effect of radioembolization is related to the internal radiotherapy and not to the embolization. It requires several rigorous steps, involving interventional radiologists, nuclear physicians, radiopharmacists and radiophysicists: A simulation step with albumin macroaggregates, dosimetry, and the treatment phase. Radioembolization is available in France for about ten years. It has been validated in patients with exclusive liver metastases and refractory to systemic treatments in few studies with small population, allowing its reimbursement in this indication. Recent large phase III studies have evaluated this technique in combination with chemotherapy, in 1st and 2nd line of treatment. Despite clear antitumor activity, showing an improvement in local control, these studies did not show any benefit in overall survival. Improved dosimetry techniques, better patient selection, and combinations with treatments likely to have synergistic biological effects could lead to reconsideration of the role of radioembolization in early-line treatment. [ABSTRACT FROM AUTHOR]

The Gastrin-Releasing Peptide Receptor (GRPR) is over-expressed in estrogen receptor (ER) positive breast tumors and related metastatic lymph nodes offering the opportunity of imaging and therapy of luminal tumors. 68Ga-RM2 binding and 18F-FDG binding in tumoral zones were measured and compared using tissue micro-imaging with a beta imager on 14 breast cancer samples (10 primaries and 4 associated metastatic lymph nodes). Results were then assessed against ER expression, progesterone receptor (PR) expression, HER2 over-expression or not and Ki-67 expression. GRPR immunohistochemistry (IHC) was also performed on all samples. We also retrospectively compared 68Ga-RM2 and 18F-FDG bindings to 18F-FDG SUVmax on the pre-therapeutic PET/CT examination, if available. 68Ga-RM2 binding was significantly higher in tumors expressing GRPR on IHC than in GRPR-negative tumors (P = 0.022). In ER+ tumors, binding of 68Ga-RM2 was significantly higher than 18F-FDG (P = 0.015). In tumors with low Ki-67, 68Ga-RM2 binding was also significantly increased compared to 18F-FDG (P = 0.029). Overall, the binding of 68Ga-RM2 and 18F-FDG displayed an opposite pattern in tumor samples and 68Ga-RM2 binding was significantly higher in tumors that had low 18F-FDG binding (P = 0.021). This inverse correlation was also documented in the few patients in whom a 18F-FDG PET/CT examination before surgery was available. Findings from this in vitro study suggest that GRPR targeting can be an alternative to 18F-FDG imaging in ER+ breast tumors. Moreover, because GRPR antagonists can also be labeled with lutetium-177 this opens new avenues for targeted radionuclide therapy in the subset of patients with progressive metastatic disease following conventional treatments. [ABSTRACT FROM AUTHOR]

Purpose: To assess diagnostic accuracy of F-FDG PET/CT at 3 months for the detection of local recurrence after radiofrequency ablation (RFA) of lung metastases. Methods: The PET/CT scan at 3 months was compared with a baseline PET/CT scan from a maximum of 2 months before RFA, with the reference standard as recurrence diagnosed by CT during a 12-month follow-up. Local recurrence was diagnosed on the PET/CT scan if lesional uptake was greater than the mediastinal background. Maximum standardized uptake values (SUVmax) were recorded. ROC curve analysis for SUVmax was performed. Overall survival (OS) and time to local relapse were computed from the date of RFA using the Kaplan-Meier method (www.clinicaltrials.gov: NCT 00382252). Results: Between 2005 and 2009, 89 patients (mean age 65 years) underwent RFA for 115 lung metastases (mean size 16.2 ± 6.9 mm). The median SUVmax before RFA was 5.8 ± 4. PET/CT at 3 months and the reference standard were available in 77 patients and 100 lesions. Accuracy was 66.00 % (95 % CI 55.85-75.18 %), sensitivity 90.91 % (95 % CI 58.72-99.77 %), specificity 62.92 % (95 % CI 52.03-72.93 %), PPV 23.26 % (95 % CI 11.76-38.63 %), and NPV 98.25 % (95 % CI 90.61-99.96 %). One-year OS was 94.2 % (95 % CI 86.6-97.5 %) and the probability of being free of local recurrence 1 year after RFA was 84.6 % (95 % CI 75.0-90.8 %). Conclusion: The specificity of PET/CT at 3 months is low because of persistent inflammation, especially when the lesion is close to the pleura. This technique is useful for its negative predictive value, but positive findings need to be confirmed by histology before new treatment is planned. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the relevance of PET/CT and 18 F-FDG as a strategy for response evaluation after chemoradiotherapy for anal cancer. For this, the performance of posttreatment 18 F-FDG PET/CT, the impact on patient care, and the predictive value of metabolic response were assessed. Methods: This was a retrospective and multicenter analysis of 87 patients treated by chemoradiotherapy for anal squamous cell carcinoma between October 2007 and October 2013. All patients underwent systematic posttreatment 18 F-FDG PET/CT and were followed with at least a clinical examination every 4 mo for 2 y and every 6 mo thereafter. Disease progression was confirmed by biopsy for all patients in the case of local recurrence before surgery. Kaplan-Meier and Cox regression models were used to test for associations between metabolic or clinical endpoints and progression-free survival (PFS) or cause-specific survival (CSS). Results: The median follow-up was 25 mo. 18 F-FDG PET/CT was performed 1-8 mo (median, 4 mo) after completion of chemoradiotherapy. Overall, 25 patients relapsed and 13 died. The posttherapy 18 F-FDG PET/CT did not show any abnormal 18 F-FDG uptake (complete metabolic response [CMR]) in 55 patients whereas 32 displayed incomplete response (non-CMR): 15 patients with partial response and 17 with disease progression. The sensitivity of 18 F-FDG PET/CT to detect residual tumor tissue was 92% (95% confidence interval [CI], 75%-97%), specificity was 85% (95% CI, 75%-92%), positive predictive value was 72% (95% CI, 61%-90%), and negative predictive value was 96.4% (95% CI, 90%-98.7%). The 2-y PFS was 96% (95% CI, 90-100) for patients with CMR and 28% (95% CI, 14-47) for non-CMR patients ( P < 0.0001). The 2-y CSS was 100% for patients with CMR and 59% (95% CI, 42-84) for those without CMR ( P < 0.0001). 18 F-FDG PET/CT changed patient management in 14 cases (16%), with relevant modifications in 12 (14%). A Cox proportional hazards model of survival outcome indicated that a CMR was the only significant predictor of PFS and CSS ( P < 0.0001). Conclusion: 18 F-FDG PET/CT shows good accuracy in posttreatment evaluation of anal cancer and has a relevant impact on patient management. Moreover, CMR is associated with good survival outcome. Thus, 18 F-FDG PET/CT may play a significant role during posttreatment follow-up of anal cancer., (© 2017 by the Society of Nuclear Medicine and Molecular Imaging.)

Whole-body (131I) scintigraphy (WBS) is used to detect residual or metastatic tissue during treatment of differentiated thyroid carcinoma in combination with thyroglobulin (Tg) and ultrasonography of the neck. It is a highly sensitive method, but there is a high rate of false positives. We report the case of a 52-year-old woman with false-positive iodine accumulation in a benign cystic mesothelioma discovered during treatment for a oncocytic follicular thyroid carcinoma (stage pT2 pNx Mx). This lesion was detected by WBS and confirmed by surgery and histopathologic analysis.