Association of 18F- fluorodeoxyglucose uptake with the expression of metabolism-related molecules in papillary thyroid cancer

OBJECTIVES

18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) is a diagnostic imaging method that is based on the Warburg effect, which is the increased uptake of glucose through aerobic glycolysis in cancer cells. The diagnostic value of 18F-FDG-PET/CT for thyroid cancer is controversial. However, uptake of 18F-FDG and the corresponding maximum standardized uptake value (SUVmax) is expected to reflect the metabolic status of cancer cells. In the present study, we sought to determine the relationship between 18F-FDG uptake and tumor metabolism- associated factors.

METHODS

This was a single-center retrospective study. In the present study, SUVmax was compared with the expression of hexokinase 2 (HK2), glucose transporter 1 (GLUT1), vascular endothelial growth factor (VEGF), and glutaminase 1 (GLS1) in 41 patients with thyroid cancer.

RESULTS

GLS1 expression was found to be moderately correlated with SUVmax (p < 0.001, r = 0.51), whereas HK2 and VEGF expression were weakly correlated (p = 0.011, r = 0.28, p = 0.008, r = 0.29, respectively) and GLUT1 did not correlate with SUVmax (p = 0.62, r = 0.06).

CONCLUSION

Our findings suggest 18F-FDG PET/CT reflects GLS1 expression in thyroid cancer and could be used to select suitable candidates for GLS1 inhibitor treatment.

Early Structural, Biochemical, and Metabolic Responses to Anlotinib in Patients With Progressive Radioactive Iodine Refractory Differentiated Thyroid Cancer

OBJECTIVE

We aimed to assess the early efficacy of anlotinib in patients with progressive radioactive iodine refractory differentiated thyroid cancer at the structural, biochemical, and metabolic levels.

METHODS

Ten eligible patients were prospectively enrolled to receive anlotinib. Their responses were assessed at 6 weeks. Apart from the structural response according to Response Evaluation Criteria in Solid Tumors version 1.1, the biochemical response was assessed by serum thyroglobulin (Tg), and the metabolic response was assessed by 2-deoxy-2-[18F] fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) according to the European Organization for Research and Treatment of Cancer criteria. A safety profile was recorded.

RESULTS

Structurally controlled disease (20% partial response + 80% stable disease) was observed in all patients. The median longest diameter of target lesions shrank from 20.8 mm (IQR, 14.9-27.5) to 17.0 mm (IQR, 14.1-23.7) (P < .001), and the average shrinkage rate was -15.1 ± 14.1%. Sharp serum Tg reduction by 72.8 ± 16.4% was observed in 8 measurable patients. The 18F-FDG PET/CT-mapped glucose metabolic response was not quite comparable to the structural response, with 90% of the patients having controlled disease (30% partial metabolic response + 60% stable metabolic disease), whereas 10% presented progressive metabolic disease. The most common treatment-emergent adverse events (AEs) were hypertension (100%) and proteinuria (70%). Most AEs were grade 1 or 2, whereas grade 3 AEs occurred only in hypertension.

CONCLUSION

Anlotinib is generally well tolerated and can bring early disease control within the initial 6 weeks of treatment. The sharp biochemical response suggests Tg to be an early sensitive biomarker to anlotinib, whereas the heterogeneous metabolic response might play a complementary role.

18F-FDG-PET/CT in SARS-CoV-2 infection and its sequelae

In recent months, much of the scientific efforts have focused on research on SARSCoV-2 infection and its consequences in humans. Still, many aspects remain unknown. It is known that the damage caused by SARS-CoV-2 is multifactorial and that its extension goes beyond lung inflammation and the acute phase, with the appearance of numerous complications and sequelae. To date, knowledge about the usefulness of 18F-FDG-PET/CT in the acute phase has been limited to the incidental detection of SARS-CoV-2 unsuspected pneumonia. Recent studies have been appearing collecting the findings of 18F-FDG-PET/CT in long COVID-19 or persistent COVID-19 state as well as the alterations caused after mass vaccination of the population in the metabolic studies. This work aims to review the existing literature focusing on these three issues and to briefly present our own preliminary experience.

Role of 18F-FDG-PET/CT in patients with differentiated thyroid cancer with biochemical incomplete or indeterminate response to treatment

OBJECTIVES

To assess the value of ¹⁸F-FDG-PET/CT for detecting recurrent/persistent disease in patients with biochemical incomplete (BIR) or indeterminate response (IR) and to assess the impact of ¹⁸F-FDG-PET/CT on the therapeutic management of these patients.

METHODS

The study included patients with BIR, in whom ¹⁸F-FDG PET/CT was used within the diagnostic algorithm from our database. Patients with IR referred to our hospital with the ¹⁸F-FDG PET/CT already performed were also enrolled. All patients had neck ultrasonography with no structural changes. A change in therapeutic approach was defined as repeat surgery; administration of external beam radiotherapy; and/or the start of systemic therapy.

RESULTS

Sixty patients (85% women) aged 18-86 years were enrolled in this retrospective study. Of these, 75% had BIR and 25% IR. Increased FDG uptake suggesting locoregional lesions was seen in 40% of patients. Sensitivity, specificity, and diagnostic accuracy of ¹⁸F-FDG PET/CT to detect local disease were 95%, 87.5% and 90% respectively. The therapeutic approach was modified in 50% of patients with locoregional lesions.

CONCLUSIONS

Our study confirmed that ¹⁸F-FDG-PET/CT is a useful tool for detecting locoregional recurrence in thyroid cancer patients with BIR or IR with conflicting findings in standard diagnostic procedures. In 50% of patients with locoregional lesions, there was an immediate change in the treatment approach.

Criteria of metabolic response to immunotherapy

Therapy response assessment is one of the most challenging indications of imaging studies. In clinical trial patients is usually measured with standardized response criteria. However, in the clinical practice, many studies are carried out in which the clinical question is whether or not the treatment is being effective. Answering this question is one of the greatest challenges for diagnostic imaging physicians, especially when a new treatment modality is being introduced, whose effects on tumoral lesions are firstly poorly understood. We have an essential role in the introduction of new therapies, assessing their effects and benefits. The knowledge of these effects has led to the development of many response criteria that, despite being applicable only in clinical trials, offer us information on how to interpret the findings in clinical practice.

18F-FDG-PET/CT angiography in the diagnosis of infective endocarditis and cardiac device infection in adult patients with congenital heart disease and prosthetic material

OBJECTIVES

Infective endocarditis (IE) and cardiac device infection (CDI) are a major complication in the growing number of patients with congenital heart disease (CHD) reaching adulthood. We aimed to evaluate the added value of ¹⁸F-FDG-PET/CT angiography (PET/CTA) in the diagnosis of IE-CDI in adults with CHD and intravascular or intracardiac prosthetic material, in whom echocardiography (ECHO) and modified Duke Criteria (DC) have limitations because of the patients' complex anatomy.

METHODS

A prospective study was conducted in a referral center with multidisciplinary IE and CHD Units. PET/CTA and ECHO findings were compared in consecutive adult (≥18years) patients with CHD who have prosthetic material and suspected IE-CDI. The initial diagnosis using the DC and the diagnosis with the additional PET/CTA data (DC+PET/CTA) were compared with the final diagnostic consensus established by an expert team at three months.

RESULTS

Between November-2012 and April-2017, 25 patients (15 men; median age 40years) were included. Cases were initially classified as definite in 8 (32%), possible in 14 (56%) and rejected in 3 (12%). DC+PET/CTA allowed reclassification of 12/14 (86%) cases initially identified as possible IE. The sensitivity, specificity, PPV, NPV, and accuracy of DC at IE suspicion were 39.1%/83.3%/90.4%/25.5%/61.2%, respectively. The diagnostic performance increased significantly with addition of PET/CTA data: 87%/83.3%/95.4%/61.5%/85.1%, respectively. PET/CTA also provided an alternative diagnosis in 3 patients with rejected IE, and detected pulmonary embolisms in 3 patients.

CONCLUSIONS

PET/CTA was a useful diagnostic tool in the complex group of adult patients with CHD who have cardiac or intravascular prosthetic material and suspected IE or CDI, providing added diagnostic value to the modified DC (increased sensitivity) and improving case classification.

Optimisation of metabolic criteria in the prognostic assessment in patients with lymphoma. A multicentre study

OBJECTIVE

To compare sensitivity, specificity and predictive value of Deauville score (DS) vs. ΔSUVmax in interim-treatment PET (iPET) and end-treatment PET (ePET), in patients with diffuse large B cell lymphoma (DLBCL), Hodgkin lymphoma (HL), and follicular lymphoma (FL).

METHOD

Retrospective longitudinal multicentre study including 138 patients (46 DLBCL, 46 HL, 46 FL), on whom 3 ¹⁸F-FDG PET/CT were performed: baseline, iPET, and ePET. Visual (DS) and semi-quantitative (ΔSUVmax) parameters were determined for iPET and ePET. Predictive value was determined in relation to disease-free interval.

RESULTS

Statistical analysis. iPET for DLBCL, HL, and FL: 1) sensitivity of DS: 76.92/83.33/61.53%; specificity: 78.78/85/81.81%; 2) sensitivity of ΔSUVmax: 53.84/83.33/61.53%; specificity: 87.87/87.50/78.78%. ePET for DLBCL, HL and FL: 1) sensitivity of DS: 61.53/83.33/69.23%; specificity: 90.90/85/87.87%; 2) sensitivity of ΔSUVmax: 69.23/83.33/69.23%; specificity: 90.90/87.50/84.84%. Predictive assessment. iPET study: in DLBCL, DS resulted in 10.3% recurrence of negative iPET, and 17.1% in ΔSUVmax at disease-free interval; in HL, both parameters showed a 2.8% recurrence of negative iPET; in FL, DS resulted in 15.6% recurrence of negative iPET, and 16.1% in ΔSUVmax, with no statistical significance. ePET study: in DLBCL, DS resulted in 14.3% recurrence of negative ePET, and 11.8% in ΔSUVmax at disease-free interval; in HL and FL, both methods showed 2.8 and 12.5% recurrence in negative ePET, respectively.

CONCLUSION

DS and ΔSUVmax did not show significant differences in DLBCL, HL and FL. Their predictive value also did not show significant differences in HL and FL. In DLBCL, DS was higher in iPET, and ΔSUVmax in ePET.

18F-FDG PET/CT as predictor of tumour biology and prognosis in epithelial ovarian carcinoma

OBJECTIVE

To investigate the relationship between maximum standardised uptake value (SUVmax) of ovarian lesions and histopathology subtypes, and their involvement in the response and prognosis of patients with epithelial ovarian carcinoma (EOC).

MATERIAL AND METHODS

A retrospective analysis of 31 patients with EOC and ¹⁸F-FDG-PET/CT before treatment, including an assessment of the SUVmax of ovarian lesion. Histopathological diagnosis and follow-up was performed. A study was made on the relationship between the SUVmax and histological type (type I and II) and tumour stage, as well as the role of various parameters (SUVmax, histology, stage) on the patient outcomes (complete response [CR], overall survival [OS], disease-free survival [DFS], and disease-free [DF] status, at 12 and 24 months).

RESULTS

The medium SUVmax in type I lesions was lower than in type II (6.3 and 9.3, respectively; P=.03). A 7.1 cut-off was set for SUVmax in order to identify type II EOC (sensitivity: 77.8%, specificity: 69.2%; AUC=0.748; P=.02). No significant relationship was found between tumour stage and SUVmax. CR was more common in early stages; relative risk (RR) of 1.64; P=.003, as well as in type I tumours and a lower SUVmax. Tumour stage was decisive in DFS (P=.04), LE24m (0.07) and OS (P=.08). Longer DFS and a higher percentage of DF 24m were observed in type I tumours (RR: 1.32; P=.26).

CONCLUSIONS

SUVmax was related to EOC histology, so could predict the response and prognosis of these patients. No association was found between glycolytic activity of the primary tumor with the response and prognosis.

¹⁸F-FDG-PET/CT in staging, restaging, and treatment response assessment of male breast cancer

PURPOSE

Male breast cancer (BC) is a rare disease, with patterns different from those found in women. Most tumors are detected at more advanced stages than in women. The aim of this study was to analyze the performance of [18F]fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT) in staging, restaging, and therapy response assessment.

METHODS

We performed a systematic analysis in the database of Saint-Louis Hospital to identify male patients with BC referred for PET/CT. (18)F-FDG-PET/CT findings considered suspicious for malignancy were compared to biopsy results, further work-up and/or patient follow-up of at least 6 months. Performances of (18)F-FDG-PET/CT were compared to that of conventional imaging (CI) using the McNemar test. The impact of PET/CT on management was evaluated.

RESULTS

During 6 consecutive years, among 12,692 (18)F-FDG-PET/CT oncology studies, 30 were performed in 15 men with BC: 7 examinations for initial staging, 11 for restaging, and 12 for response assessment. Tumors profile was ER+ and one had HER2 overexpression. PET/CT sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect distant metastases were 100%, 67%, 86%, 100% and 89%, respectively. PET/CT was more informative than CI in 40% of studies (p=0.03; 95% confidence interval: 3.26 - 40%). Findings from (18)F-FDG-PET/CT led to modification in the planned treatment in 13/30 cases (43%).

CONCLUSION

Although all the tumors were ER+, primary lesions and metastases were diagnosed with high sensitivity. (18)F-FDG-PET/CT seems to be a powerful imaging method to perform staging, restaging and treatment response assessment in male patients with BC.

¹⁸F-FDG-PET/CT in malignant mesothelioma

It is well known the useful role of ¹⁸F-FDG-PET/CT for differential diagnosis between benign and malignant disease, for staging, for monitoring response and for prognosis regarding mesothelioma. Recently, literature was enriched with new interesting studies regarding the potential applications of ¹⁸F-FDG-PET/CT in this field. The purpose of this review is to evaluate articles published on line (PubMed) from January 2011 until October 2012 in order to obtain an overview of recent progress of molecular imaging in malignant mesothelioma. The main topics concern the use of ¹⁸F-FDG-PET/CT in radiation therapy planning, monitoring of treatment (surgery/chemotherapy) response and prognosis assessment.