Prognostic role and characteristics of the indeterminate response in differentiated thyroid cancer: a systematic review.

PURPOSE: The management of differentiated thyroid cancer (DTC) is actually based on a dynamic risk stratification based on classes of response to the therapy. Indeterminate response (IR) includes a heterogeneous group of patients with different characteristics, particularly different Tg and AbTg levels and/or imaging findings. The aim of systematic review (SR) is to evaluate the prognosis, diagnostic findings and other characteristics of patients in the IR class. METHODS: A wide literature search in the Scopus, PubMed/MEDLINE and Web of Science databases was performed to find published articles on patients with DTC and IR after treatment. The quality assessment of studies was carried out using QUADAS-2 evaluation. RESULTS: Eight articles were included in the systematic review. Six studies evaluated the prognosis and the prognostic factor in patients with IR, one study evaluated the role of 2-[18F]FDG PET-CT in the management of patients with IR and biochemical incomplete response and one study the risk factors for IR. CONCLUSION: Patients with DTC and IR to therapy have a probability of disease relapse < 15%. Tg value could be a predictor of disease progression. The role of 2-[18F]FDG PET-CT needs to be further investigated.

18F-FDG PET or PET/CT role in plasmacytoma: A systematic review. / Papel de la 18F-FDG PET o PET/TC en el plasmocitoma: una revisión sistemática.

BACKGROUND: The metabolic behavior of plasmacytoma at 18F-FDG PET/CT is not yet clear. OBJECTIVE: The aim of this systematic review was to analyze published data about the role of 18F-FDG PET or PET/CT in patients affected by plasmacytoma. METHODS: Acomprehensive computer literature search of the Scopus, PubMed/MEDLINE, Embase and Cochrane Library databases was conducted including articles up to July 2019 to find relevant published papers about the performance of 18F-FDG PET and PET/CT in plasmacytoma. RESULTS: The comprehensive computer literature search revealed 371 articles. On reviewing the titles and abstracts, 363 articles were excluded because the reported data were not within the field of interest of this review. Eight articles were selected and retrieved in full-text version. From the analyses of the selected studies, the following main findings have been founded: 1) plasmacytoma generally is a 18F-FDG-avid tumor and PET/CT had good diagnostic performance with high sensitivity; 2) 18F-FDG PET/CT influenced patient management in most cases avoiding useless therapies and choosing the best therapeutic approach; 3) prognostic value of PET/CT qualitative and semiquantitative parameters is only suggested with controversial reports. CONCLUSION: Despite several limitations affect this analysis, especially related to the low number of articles and patients studied, plasmacytoma looks to be an 18F-FDG-avid tumor in most of the cases; 18F-FDG PET or PET/CT had good diagnostic performance and had a significant clinical impact in change of therapeutic approach. Moreover, a possible prognostic role of PET/CT features is described.

18F-FDG PET/CT brown fat detection: Differences between adult and pediatric population in a 12 year experience. / Detección de grasa parda en la PET/TC con 18F-FDG: diferencias entre la población adulta y pediátrica en una experiencia de 12 años.

PURPOSE: To analyze epidemiological and anthropometric features of patients with brown adipose tissue (BAT) activation detected by fluorine18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). MATERIAL AND METHODS: From 2005 to 2017, 818 18F-FDG PET/CT studies positive for BAT detection were retrospectively included, 742 examinations performed on the adult population and 76 PET/CT on the pediatric population. A Chi-squared test was performed to compare features distribution between the adult and pediatric patients. RESULTS: Adults showed a higher rate of BAT detection in females (79% vs. 61%, P<0.001) and in hyperglycaemic patients (>100mg/dL) (24% vs. 16%, P=0.02), no significant difference was found with regard to overweight patients (BMI>25kg/m2) (22% vs. 20%, P=.55). Considering females only, the adults showed a higher rate of BAT detection both in hyperglycaemic (83% vs. 42%, P<0.001) and overweight patients (80% vs. 67%, P=0.005). In both populations BAT activation happened more frequently in cold seasons; there was no significant distribution difference with regard to season of birth (P=0.2). CONCLUSIONS: Sex, glycemia and BMI play a major role in predicting BAT activation, with significant differences between adults and pediatric patients. Cold exposure is confirmed as an important predicting factor, while season of birth is not significant.

Role of 18F-FDG PET/CT in restaging and follow-up of patients with uterine sarcomas. / 18F-FDG PET/TC en reestadificación y seguimiento de pacientes con sarcomas uterinos.

PURPOSE: Uterine sarcomas are rare tumors with poor prognosis due to the high recurrence rates. The current role of 18F-FDG PET/CT in the post-therapy surveillance is not established yet. MATERIALS AND METHODS: Forty-one women with uterine sarcoma underwent 73 18F-FDG PET/CT for restaging in suspected recurrence or during follow-up in asymptomatic patients. Histopathology results and/or clinical/imaging follow-up for at least 12 months were considered the reference standard. The diagnostic accuracy and clinical impact of 18F-FDG PET/CT was calculated. RESULTS: Thirty-three 18F-FDG PET/CT were positive, while the remaining 40 studies were negative. The overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 18F-FDG PET/CT were 88%, 98%, 97%, 91% and 93%, respectively. Considering patients with clinical or radiological suspicion of recurrence (n=47) and those during follow-up (n=26), sensitivity, specificity, PPV, NPV and accuracy of 18F-FDG PET/CT were 89%, 100%, 100%, 86% and 94%, and 80%, 95%, 80%, 95% and 92%, respectively. 18F-FDG PET/CT had a positive clinical impact in 9/73 (12%) studies and changed the clinical management in 8/41 (20%) patients. CONCLUSIONS: 18F-FDG PET/CT seems to be an accurate method for detection and localization of local and distant recurrence in patients with uterine sarcoma with good sensitivity and specificity and significant impact on clinical decision making.

Clinical and prognostic value of 18F-FDG PET/CT in recurrent endometrial carcinoma. / Valor clínico y pronóstico de la PET/TC con 18F-FDG en el cáncer de endometrio recurrente.

PURPOSE: Endometrial carcinoma (EC) is a cancer with a good overall prognosis, except in cases of recurrent or advanced EC. The aim of this study was to assess the diagnostic performance, the prognostic value and the impact on therapeutic management of 18F-FDG PET/CT in suspected recurrent EC. MATERIALS AND METHODS: We retrospectively evaluated 157 patients with histologically proven EC and restaging 18F-FDG PET/CT for suspected recurrence. The PET images were analyzed visually and semi-quantitatively by measuring SUVmax, MTV and TLG. A combination of clinical/imaging follow-up and/or histopathology was taken as reference standard. Progression-free survival (PFS) and overall survival (OS) were computed using Kaplan-Meier curves. RESULTS: Seventy-nine patients had positive 18F-FDG PET/CT showing the presence of at least one hypermetabolic lesion consistent with recurrence, while the remaining 78 were negative. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-FDG PET/CT were 96%, 99%, 99%, 96%, 97%, respectively, and were higher compared to conventional imaging: 97%, 62%, 72%, 96%, 80%. After a mean follow-up of 39months, relapse/progression occurred in 58 patients and death in 37 with an average time of 22.1 and 27.6months, respectively. A positive 18F-FDG PET/CT and advanced FIGO stage were significantly associated with shorter PFS and OS. PET/CT results had a significant impact on therapeutic approach in 33 patients: avoiding unnecessary therapies in 28 and modifying therapy in 5. CONCLUSIONS: 18F-FDG PET/CT has a very good diagnostic performance in patients with suspected recurrent EC and has an important prognostic value in assessing PFS and OS. Moreover, PET/CT allowed for a change in treatment decision in about 20% of cases.

Different uptake of 123I-MIBG in the two main liver lobes: A persistant unsolved mistery. / Diferente captación de 123I-MIBG en los 2 lóbulos hepáticos principales: un misterio persistente sin resolver.

PURPOSE: After radiopharmaceutical injection, a heightened 123I-MIBG concentration is frequently observed in the left hepatic lobe compared to the right one, but the reason of this finding remains unknown. Our aim was to retrospectively analyze the different 123I-MIBG uptake pattern between the two hepatic lobes and correlate our results with some epidemiological/clinical features. MATERIAL AND METHODS: Ninety-four 123I-MIBG scintigraphies from 71 patients were selected. Regions of interest were drawn in the right and left lobes using transverse tomographic sections and left to right activity ratios (L/R ratio) were calculated at 6 and 24h after radiotracer administration. RESULTS: Twenty-seven examinations were positive for hypermetabolic lesions while the remaining 67 were negative. In all cases mean early and delayed L/R ratios were greater than 1.00; average early L/R ratio was 1.37 and delayed L/R ratio 1.52. The delayed L/R ratio was significantly higher than the early one. There was no difference in the L/R ratios with regard to age, gender, primary disease and result of scintigraphy. CONCLUSIONS: 123I-MIBG uptake was higher in left hepatic lobe compared to right and this ratio did not correlate with any epidemiological or clinical feature. The reason of this metabolic is not yet explained and some biomolecular hypotheses could be tested in 3D dynamic in vitro models.

18F-FDG PET/CT follow-up of follicular dendritic cell sarcoma.

Follicular dendritic cell sarcoma (FDCS) is a rare lymphoid neoplasm which occurs mainly in lymph nodes, especially cervical and mediastinal; it can be difficult to diagnose and often is misdiagnosed. Its pathogenesis is still not clear, like its evolution. We report a case of 60-year-old woman with FDCS of left lateral cervical node followed for almost 10 years, after a left selective neck dissection, who underwent five 18F-FDG PET/CT. This technique has proven to be an useful method for the management of this patient, mainly for the follow up, detection of relapse and therapy response evaluation.

Thyroid nodules with indeterminate cytology: prospective comparison between 18F-FDG-PET/CT, multiparametric neck ultrasonography, 99mTc-MIBI scintigraphy and histology.

PURPOSE: To evaluate the role of (18)F-flurodeoxiglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT) in predicting malignancy of thyroid nodules with indeterminate cytology. PATIENTS AND METHODS: We analysed 87 patients who have been scheduled to undergo surgery for thyroid nodule with indeterminate cytology. All patients underwent (18)F-FDG-PET/CT, multiparametric neck ultrasonography (MPUS), and (99m)Tc-methoxyisobutylisonitrile scintigraphy ((99m)Tc-MIBI-scan). Histopathology was the standard of reference. We compared the sensitivity (SE), specificity (SP), accuracy (AC), positive (PPV) and negative predictive (NPV) values of (18)F-FDG-PET/CT with those of (99m)Tc-MIBI-scan and MPUS in detecting cancer. Univariate and multivariate analyses evaluated the association between each diagnostic tool and histopathology. RESULTS: On histopathology, 69 out of 87 nodules were found to be benign and 18 to be malignant. The SE, SP, AC, PPV and NPV of (18)F-FDG-PET/CT were 94, 58, 66, 37 and 98% respectively. The SE, AC and NPV of (18)F-FDG-PET/CT were significantly higher than those of MPUS and (99m)Tc-MIBI-scan. The association of both positive (18)F-FDG-PET/CT and MPUS (FDG+/MPUS+) showed significantly lower SE (61% vs 94%) and NPV (88% vs 98%) than (18)F-FDG-PET/CT alone, but significantly higher SP (77% vs 58%). On univariate analysis, (18)F-FDG-PET/CT and the combination of FDG+/MPUS+ and of FDG+/MIBI- were all significantly associated with histopathology. On multivariate analysis, only FDG+/MIBI- was significantly associated with histopathology. CONCLUSION: The AC of (18)F-FDG-PET /CT in detecting thyroid malignancy is higher than that of (99m)Tc-MIBI-scan and MPUS. A negative (18)F-FDG-PET/CT correctly predicts benign findings on histopathology. The association of FDG+/MPS+ is significantly more specific than (18)F-FDG-PET/CT alone in identifying differentiated thyroid cancer. A positive (18)F-FDG-PET/CT is significantly associated with malignancy when qualitative (99m)Tc-MIBI-scan is rated as negative.

Diagnostic role of (18)F-FDG-PET or PET/CT in salivary gland tumors: A systematic review.

Salivary gland tumors are rare neoplasms that have not been extensively studied with (18)F-FDG-PET- or PET/CT up to now. This review aims to evaluate the diagnostic performance of PET in this particular setting, analyzing the available literature. A comprehensive literature search in the PubMed/MEDLINE, Embase and Scopus databases was performed including articles up to November 2014, resulting in the selection of 22 articles. The studies selected suggest that: (1) PET is not useful in discriminating benign from malignant SGTs because of the overlap of uptake in both conditions; (2) PET not only is complementary to conventional imaging techniques for the staging and restaging but in some cases could also be superior to them; (3) PET may often have a highly positive impact on clinical decision making. Despite many limitations affecting the analysis, PET seems to be useful in SGTs. However, more extensive studies and cost-effectiveness analyses are desirable to determine its correct position in the diagnostic flow chart.