Appropriate timing to perform an interim 18F-FDG PET/CT in patients with nasal-type extranodal natural killer/T cell lymphoma.

Interim 18F-FDG PET/CT (I-PET) has a role in response evaluation and treatment guidance in patients with nasal-type extranodal natural killer/T cell lymphoma (ENKTL). However, there was no agreement on the timing of I-PET performed, after chemotherapy or after chemoradiotherapy. We aimed to find the appropriate timing for I-PET by assessing the prognostic value of I-PET in response evaluation in ENKTL patients. Two hundred and twenty-seven ENKTL patients who had undergone I-PET were retrospectively included. All patients were grouped based on their therapeutic strategy received, chemotherapy or chemoradiotherapy. The Deauville 5-point score (DS) was used to interpret the I-PET images. The hazard ratio (HR) and C-index were used to measure the discriminatory and prognostic capacities of I-PET performed at different times. One hundred and six patients underwent the I-PET after chemotherapy (chemotherapy group), while I-PET was performed after chemoradiotherapy in 121 patients (chemoradiotherapy group). Eighty-seven patients were classified as metabolic remission (DS score of 1-3), while the other 140 were classified as non-metabolic remission (DS score of 4-5) according to the Deauville criteria. There were no significant survival differences between patients in metabolic remission and in non-metabolic remission in either progression-free survival (PFS, p = 0.406) or overall survival (OS, p = 0.350). In the chemotherapy group, patients in metabolic remission had significantly superior PFS than patients in non-metabolic remission (p = 0.012). For OS, a discriminative trend was also found on the survival curve between patients in metabolic remission and in non-metabolic remission (p = 0.082). In the chemoradiotherapy group, there was no significant difference in PFS (P = 0.185) or OS (P = 0.627) between patients in metabolic remission and in non-metabolic remission. I-PET after chemotherapy yields higher discriminative power and has the ability for prognostic prediction in nasal-type ENKTL patients. I-PET after radiochemotherapy has no prognostic value. Thus, the appropriate timing for I-PET is after chemotherapy but before radiotherapy for response evaluation in nasal-type ENKTL patients.

Quality and consistency of clinical practice guideline recommendations for PET/CT and PET: a systematic appraisal.

OBJECTIVES: To systematically appraise the methodologies used for guidelines for positron emission tomography (PET) imaging and to compare the consistency of these recommendations. METHODS: We searched PubMed, EMBASE, four guideline databases, and Google Scholar to identify evidence-based clinical practice guidelines pertaining to the use of PET, PET/computed tomography (CT), or PET/magnetic resonance in routine practice. We assessed the quality of each guideline using the Appraisal of Guidelines for Research and Evaluation II instrument and compared recommendations regarding indications for 18F-fluorodeoxyglucose (FDG) PET/CT. RESULTS: Thirty-five guidelines for PET imaging, published between 2008 and 2021, were included. These guidelines performed well in the domains of scope and purpose (median 80.6%, inter-quartile range [IQR] 77.8-83.3%) and clarity of presentation (median 75%, IQR 69.4-83.3%), but poorly in applicability (median 27.1%, IQR 22.9-37.5%). Recommendations for 48 indications in 13 cancers were compared. Considerable inconsistencies in the direction of whether to support the use of FDG PET/CT were observed in 10 (20.1%) indications pertaining to 8 cancer types: head and neck cancer (treatment response assessment), colorectal cancer (staging in patients with stages I-III disease), esophageal cancer (staging), breast cancer (restaging and treatment response assessment), cervical cancer (staging in patients with stage < IB2 disease and treatment response assessment), ovarian cancer (restaging), pancreatic cancer (diagnosis), and sarcoma (treatment response assessment). CONCLUSIONS: Current guidelines for PET imaging vary in methodological quality and provided considerably inconsistent recommendations. Efforts are needed to improve adherence to guideline development methodologies, to synthesis high-quality evidence, and to adopt standard terminologies. PROTOCOL REGISTRATION NUMBER: PROSPERO CRD42020184965. CLINICAL RELEVANCE STATEMENT: Guidelines for PET imaging provide considerably inconsistent recommendations and vary in methodological quality. It is suggested that clinicians be critical of these recommendations when applying them in practice, that guideline developers adopt more rigorous development methodologies, and that researchers prioritize research gaps identified by current guidelines. KEY POINTS: • PET guidelines vary in methodological quality and provided inconsistent recommendations. Efforts are needed to improve methodologies, synthesize high-quality evidence, and standardize terminologies. • Among six domains of methodological quality assessed by the AGREE II tool, guidelines for PET imaging performed well in scope and purpose (median 80.6%, inter-quartile range 77.8-83.3%) and clarity of presentation (75%, 69.4-83.3%), but poorly in applicability (27.1%, 22.9-37.5%). • Among the 48 recommendations (for 13 cancer types) compared, conflicts in the direction of whether to support FDG PET/CT use were observed in 10 (20.1%), for 8 cancer types (i.e., head and neck, colorectal, esophageal, breast, cervical, ovarian, pancreatic, and sarcoma).

68Ga-PSMA PET/CT versus 18F-FDG PET/CT for detecting lesions in a case of fumarate hydratase-deficient renal cell carcinoma.

Gallium-68 (68Ga)-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) and fluorine-18-fluorodeoxyglucose(18F-FDG) PET/CT were performed for staging in a 51-year-old man with renal cell carcinoma. Compared with 18F-FDG PET/CT, no obvious tracer uptake in right renal mass and less metastatic lesions were found on 68Ga-PSMA PET/CT. Postoperative pathology demonstrated the diagnosis of fumarate hydratase-deficient renal cell carcinoma (FHRCC).

Quantifying the contribution of 18F-FDG PET to the diagnostic assessment of pediatric patients with fever of unknown origin: a systematic review and meta-analysis.

BACKGROUND: The value of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in the diagnostic assessment of pediatric fever of unknown origin is not known, and evidence from adults is not applicable. OBJECTIVE: To quantify the contribution of 18F-FDG PET to pediatric fever of unknown origin, considering its diagnostic limitations. MATERIALS AND METHODS: We searched PubMed, EMBASE and Cochrane Central Register of Controlled Trials up to Feb. 18, 2021. We included studies on patients with pediatric fever of unknown origin presenting sufficient data to calculate the likelihood of achieving definite diagnosis (based on pathology or clinical follow-up) between those with abnormal PET findings versus those with normal PET findings. We assessed the risk of bias using a modified Newcastle-Ottawa quality assessment scale and quantified the value of PET by pooling the likelihood of achieving definite diagnosis using a random-effects model. RESULTS: We included 6 studies and found that pediatric patients with abnormal PET findings were about 17 times more likely to achieve definite diagnoses than those with normal PET findings (odds ratio [OR]: 16.75, 95% confidence interval [CI] 8.0-35, P < 0.00001). Sensitivity analyses using a fixed-effect model (OR 16.91, 95% CI 8.1-35, P < 0.0001) or removing one study at a time (OR 12-20, 95% CI lower bound 3.8-8.6, 95% CI upper bound 33-45, P < 0.0001) did not significantly alter the results. Sample size (interaction P = 0.75), imaging modality (interaction P = 0.29), length of follow-up (interaction P = 0.37), fever of unknown origin subclasses (interaction P = 0.89) and geographical areas (interaction P = 0.74) of studies showed no statistically significant influence on the results. CONCLUSION: 18F-FDG PET is a promising approach in the diagnostic work-up of pediatric fever of unknown origin. Further studies are warranted to support routine use in clinical care.

The use of systematic review evidence to support the development of guidelines for positron emission tomography: a cross-sectional survey.

OBJECTIVES: To examine to what degree guidelines for PET and PET/CT used systematic review evidence. METHODS: The latest version of guidelines for PET, PET/CT or PET/MRI published in English in PubMed until December 2019 was analysed in two categories: (1) for indications, if mainly discussing the appropriate use of PET in diverse conditions; (2) for procedures, if providing step-by-step instructions for imaging. We surveyed the general characteristics and the use of systematic review evidence for developing recommendations across all guidelines, and surveyed the citation of evidence for five recommendation topics in guidelines for procedures. RESULTS: Forty-seven guidelines, published between 2004 and 2020, were included. Guidelines for indications were developed mainly on systematic reviews (13 of 19, 68.4%). Among those, 12 (63.2%) reported the level of evidence, 4 (21.1%) reported the strength of recommendations, 3 (15.8%) described external review and 7 (36.8%) involved methodologists. Guidelines for procedures were seldom developed on systematic reviews (1 of 27, 3.7%). Among those, 1 (3.7%) reported the level of evidence, 1 (3.7%) reported the strength of recommendations, 3 (11.1%) described external review and 1 (3.7%) involved methodologists. Systematic review evidence was cited by 2 (7.4%) procedure guidelines per recommendation topic in median. CONCLUSION: The use of systematic review evidence for developing recommendations among PET or PET/CT guidelines was suboptimal. While our survey is an icebreaking attempt to explore a key element (i.e. use of systematic review evidence) for developing nuclear medicine guidelines, assessments of other domains of guideline quality may help capture the entire picture. KEY POINTS: • The use of systematic review evidence for developing recommendations among guidelines for PET or PET/CT was suboptimal. • Only 13 (68.4%) guidelines for indications and 1 (3.7%) guideline for procedures systematically reviewed the literature during guideline development. • For each recommendation topic we examined, only a median of 2 (7.4%) procedure guidelines cited systematic review evidence.

The hypoglossal nerve palsy involved by papillary thyroid carcinoma detected on 18F-FDG PET/MRI.

A 51-year-old woman with papillary thyroid cancer (PTC) complained of headache.Physical examination found the tongue derivation torightside. Fluorine-18-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI) detected a hypermetabolic soft-tissue mass in the right retropharyngeal carotid space, where the nasopharyngeal carotid segment of right hypoglossal nerve passing inferiorly. The musculature in the right side of tongue was inflammatory instead of fatty infiltration, with hyperintense on T2-weighted image and hypermetabolism on PET. These images together indicated the early phase of hypoglossal nerve palsy caused by PTC invasion.

18F-FDG PET/CT imaging for a solitary primary bone lymphoma of the maxilla.

Primary bone lymphoma (PBL) is a rare primary extranodal lymphoma. It can occur in many parts of the body but rarely in the maxilla. We describe a case of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) imaging revealed solitary osseous lytic lesion with intense uptake in the maxilla, suggesting a primary skeletal malignancy. The subsequent histopathologic examination confirmed the diagnosis of high-grade B-cell lymphoma (HGBL).

[The Application Value of True Whole-body PET/CT Scanning Protocol in Patients of Extranodal NK/T Cell Lymphoma].

OBJECTIVE: To assess the staging, restaging, and treatment strategy determination of extranodal NK/T cell lymphoma (ENKT) by PET/CT real body (true whole-body, TWB) imaging, which is superior to PET/CT limitation of the whole body (limited whole-body, LWB, from skull vertex to upper thighs) by adding 'distal lower extremity' images. METHODS: TWB 18F-FDG PET/CT studies performed for staging and follow-up of ENKTL patients between January 2012 and September 2017 were retrospectively reviewed. Patients in staging group received TWB PET/CT evaluation for staging at the first diagnosis. In follow-up group, patients received follow-up evalution with TWB PET/CT and progressive disease (PD) in the LWB range with or without clinical diagnosis or suspicion before follow-up examination, and then divided into four subgroups: staging (+) PD (－), staging (+) PD (+), staging (－) PD (－), staging (－) PD (+). Then the percentage of unexpected ENKTL lesions found at the distal extremity (outside the LWB range) (P1), and the percentage of changes in the staging, restaging/outcome evaluation (P2) in each group were recorded. RESULTS: Among the 225 patients in the staging group, 200 (88.9%) had tumors confined to LWB, while P1 was 11.1% (25 cases) and P2 was 0.4% (1 case). In the follow-up group, the P1 in staging (+) PD (－)( n=85), staging (+) PD (+)( n=4), staging (－) PD (－)( n=43), staging (－) PD (+) goups ( n=15) were 1.2%, 75.0%, 0%, 26.7%, and P2 were 1.2%, 0%, 0%, 13.3%, respectively. In the follow-up group, regardless of whether the TWB PET/CT examination was performed at the initial diagnosis stage, P1 in PD (－) group and PD (+) group was 0.8 vs. 36.8% ( P<0.000 1), and P2 was 0.8% vs. 10.5% ( P<0.000 1). CONCLUSION: It is not recommended that the TWB PET/CT imaging from the top of the head to the bottom of the foot use for the first diagnosis of ENKTL patients. And for follow-up patients with no clinical evidence of tumor progression or with evidence of tumor progression but whose lesions were limited to LWB at the initial diagnosis of TWB PET/CT staging, LWB PET/CT from the top of the head to the middle of the thigh is recommended for routine follow-up. For ENKTL patients, TWB PET/CT was not performed at the initial stage of diagnosis to detect the condition of lower limbs. If the evidence of tumor progression in the LWB range appeared before the follow-up examination, TWB PET/CT was recommended for the follow-up evaluation to evaluate the systemic tumor involvement.

Physiological uptake of 18F-FDG in the vertebral bone marrow in healthy adults on PET/CT imaging.

BACKGROUND: 18F-fluorodeoxyglucose *Equal contributors. positron emission tomography/computed tomography (18F-FDG PET/CT) has proven to be a valuable imaging modality for the assessment of bone marrow condition. PURPOSE: To investigate the physiological uptake of 18F-FDG in the vertebral bone marrow in healthy adults on PET/CT imaging, and correlate the appearance with clinical factors including gender, body mass index, and age. MATERIAL AND METHODS: A total of 64 healthy individuals underwent PET/CT scan, and for each vertebral body, the mean and maximum standardized uptake value (SUVmean and SUVmax) were determined in the central slice of vertebral body on the transversal fused PET/CT image. For each individual, the FDG uptake of the four regions was obtained by averaging the SUVmean and SUVmax of the vertebrae in individual regions. RESULTS: The FDG uptake from thoracic to sacral vertebrae showed an upward trend first, then a downward trend, while that of cervical vertebrae was relatively stable. The SUVmax and SUVmean values of bone marrow in the old group (age ≥ 50 years) were significantly lower than those in the young group (age < 50 years) in all regions of the spine ( P < 0.05). FDG uptake of the whole spine showed significant negative correlation with age, and the strongest correlation was observed in lumbar spine (SUVmean: r = -0.364, P < 0.05; SUVmax: r = -0.344, P < 0.05). CONCLUSION: FDG uptake showed a tendency to increase first then decrease from thoracic to sacral vertebrae while the tendency was not obvious in cervical vertebrae. In addition, the glycolytic metabolism of all the four regions decreased with advancing age.

Diagnostic value of dual-time point 68Ga-PSMA PET/CT image for benign and malignant lesions in patients with prostate cancer.

OBJECTIVE: This study aimed to ascertain the diagnostic efficacy of routine 68Ga-PSMA imaging conducted 1 h post-injection, in conjunction with delayed imaging performed 3 h post-injection, for differentiating between benign and malignant lesions in prostate cancer (PCa) patients. METHODS: A retrospective assessment was undertaken on 44 prostate cancer patients who had undergone both routine and delayed 68Ga-PSMA PET/CT scans. Variations in SUVmax and SUVmean values in normal organs, primary prostate cancer sites, metastatic sites, and benign lesions were analyzed. Pathological examination and extended follow-ups were used to confirm all lesions. RESULTS: The study encompassed 44 patients, presenting 35 primary prostate cancer lesions, 44 metastatic lesions, and 30 benign lesions. Delayed imaging (3 h post-injection) demonstrated a decreasing trend in the SUVmax and SUVmean for the liver, blood, and spleen. Conversely, an increasing trend was observed for the parotid, lacrimal, and submandibular glands. For primary lesions, the SUVmax and SUVmean values were 17.63 ± 9.61 and 9.77 ± 5.18 during routine imaging, and 25.09 ± 15.11 and 14.05 ± 8.02 (P < 0.001) during delayed imaging. A comparable increase in SUVmax and SUVmean was seen in the delayed images for metastatic lesions when juxtaposed with routine images. Nevertheless, benign lesions displayed a decrease in SUVmax and SUVmean during delayed imaging when set against routine imaging (SUVmax: 3.56 ± 1.49 vs 2.93 ± 1.47, P = 0.001; SUVmean: 1.99 ± 0.87 vs 1.65 ± 0.87, P = 0.003). CONCLUSION: Imaging using 68Ga-PSMA PET/CT at 3 h post-injection manifested a higher uptake and target-to-background uptake in most malignant prostate cancer lesions, but a diminished uptake in benign lesions. This observation can assist clinicians in distinguishing non-specific PSMA uptake in prostate cancer patients based on PSMA PET/CT image.

Granulomatosis With Polyangiitis of Spinal Dura Presenting With "Bottle Brush Sign" on 18 F-FDG PET/CT.

ABSTRACT: A 72-year-old man with fever and weakness in both lower limbs underwent thoracolumbar MRI and 18 F-FDG PET/CT. The PET/CT scan revealed diffused FDG uptake along the spinal dura mater from T7 to S2 level like a "bottle brush." Pathologic examination after biopsy of spinal canal lesions manifested granulomatous inflammation. The blood test showed cytoplasmic antineutrophil cytoplasmic antibody (ANCA) and myeloperoxidase-ANCAs were positive, whereas the perinuclear ANCA was negative. Eventually, he was diagnosed with granulomatosis with polyangiitis.

Intracranial Phosphaturic Mesenchymal Tumor Detected by 68 Ga-DOTATATE PET/CT.

ABSTRACT: A 68 Ga-DOTATATE PET/CT scan was conducted to locate the causative tumor responsible for suspected tumor-induced osteomalacia in a 56-year-old woman. The PET/CT images showed a focus in the right occipital region. Subsequent MRI showed an extra-axial nodule in the right occipital region, mimicking a meningioma. Although rare, an intracranial phosphaturic mesenchymal tumor was still suspected because of the typical clinical settings. Finally, phosphaturic mesenchymal tumor was confirmed by the postoperative pathology.

Diagnosis of bone marrow involvement in angioimmunoblastic T-cell lymphoma should be based on both [18F]FDG-PET/CT and bone marrow biopsy findings.

OBJECTIVE: During the initial staging of certain lymphoma subtypes, 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG-PET/CT) has become an alternative to bone marrow biopsy (BMB) for detecting bone marrow (BM) involvement. However, whether [18F]FDG-PET/CT can accurately detect BM involvement in angioimmunoblastic T-cell lymphoma (AITL) remains unknown. Our study aimed to assess the diagnostic and prognostic capability of [18F]FDG-PET/CT for detecting BM involvement in AITL. Methods: This retrospective study included 84 individuals newly diagnosed with AITL who underwent baseline BMB and [18F]FDG-PET/CT. "BM involvement" was defined as one or both of the following: 1) angioimmunoblastic T-cells detected in the BM; or 2) initially heightened focal uptake having disappeared on follow-up [18F]FDG-PET/CT. The ability of [18F]FDG-PET/CT to detect BM cancerous lesions was respectively analyzed by BM involvement confirmed by BMB or the aforementioned definition as the reference standard. The patients' clinical characteristics and survival and prognostic outcomes were respectively analyzed. RESULTS: Of the 84 participants, five (6.0%) displayed positive BMB and PET/BM results, 17 (20.2%) had BMB-positive but PET/BM-negative results, eight (9.5%) showed BMB-negative but PET/BM-positive outcomes, and 54 (64.3%) displayed negative BMB and PET/BM outcomes. Using pre-defined BM involvement as the reference standard, [18F]FDG-PET/CT exhibited a specificity of 100%, sensitivity of 40%, negative predictive value (NPV) of 75%, and positive predictive value (PPV) of 100%. In contrast, using BMB-detected BM involvement as reference, [18F]FDG-PET/CT exhibited a sensitivity, specificity, PPV, and NPV of 38.5%, 76.1%, 22.7%, and 87.1%, respectively. Among patients with PET/BM-positive and BMB-negative outcomes, 62.5% (5/8) underwent upstaging from III to IV. In 58.8% (10/17) of patients who were initially diagnosed with stage II/III disease based on the [18F]FDG-PET/CT results, repeat BMB resulted in upstaging to IV. PET/BM-negative patients had a higher 3-year progression-free survival rate (38.3% vs. 22.8%, p = 0.018) and 3-year overall survival rate (64.4% vs. 34.6%, p = 0.011) than PET/BM-positive patients. CONCLUSION: In AITL patients, PET/BM-positive results may obviate the necessity for repeat BMB to ascertain confirm BM involvement. PET/BM-negative results do not definitively exclude BM involvement. The combined use of [18F]FDG-PET/CT and BMB can increase the diagnostic accuracy of BM involvement for AITL patients.

Cavernous Sinus Metastasis From Laryngeal Cancer Identified by 18F-FDG PET/MR.

ABSTRACT: Cavernous sinus metastasis from head and neck cancers is rare. We report FDG PET/MRI findings of cavernous sinus metastases from laryngeal cancer in a 56-year-old woman. The images revealed isointense lesions in the bilateral cavernous sinus on T2-weighted MR, with slight enhancement, and intense FDG uptake. The lesions were confirmed as metastases to the cavernous sinus.

Comparison of Lugano Criteria Versus RECIL and PERCIST as Prognostic Factors in Diffuse Large B-Cell Lymphoma.

OBJECTIVE: This study aimed to compare the criteria of the Lugano, RECIL, and PERCIST for prognosis in patients with diffuse large B-cell lymphoma. PATIENTS AND METHODS: We retrospectively evaluated 335 patients with diffuse large B-cell lymphoma. All patients underwent baseline 18 F-FDG PET/CT. Among them, 252 and 213 patients underwent interim PET/CT (I-PET/CT) and end-of-treatment PET/CT (EoT-PET/CT), respectively. Scans were interpreted by 2 nuclear medicine physicians using Lugano, RECIL, and PERCIST. RECIL and PERCIST were compared with Lugano for predicting progression-free survival (PFS) and overall survival (OS). RESULTS: All 3 response criteria could be used to predict PFS and OS. In I-PET/CT, the concordance index of Lugano in predicting PFS and OS was higher than that of RECIL (both P = 0.043) or PERCIST ( P = 0.008 and P = 0.034, respectively). In EoT-PET/CT, the concordance index of Lugano for predicting PFS and OS was similar to RECIL and not significantly different from PERCIST ( P = 0.597 and P = 0.231, respectively). CONCLUSIONS: For I-PET/CT, using the Lugano criteria is more accurate than RECIL or PERCIST in predicting PFS and OS. However, for EoT-PET/CT, the PERCIST criteria are minimally better.

Lactate Dehydrogenase A is Associated with Elevated FDG Metabolism, Radioiodine Non-avidity, and Poor Prognosis in Differentiated Thyroid Cancer.

RATIONALE AND OBJECTIVES: The role of lactate dehydrogenase A (LDHA) expression in differentiated thyroid cancer (DTC), especially in radioiodine-refractory DTC, remains unclear. The aim of this study was to analyse the relationships and the prognostic value of LDHA, glycolysis, and radioactive iodine (RAI) avidity in DTC. METHODS: DTC patients who underwent 18F-FDG PET/CT and subsequent total thyroidectomy or metastasectomy were enroled. The expression levels of LDHA, glucose transporters (Glut) and Ki67 proteins in tumour tissue were measured using immunohistochemistry. The maximum standardised uptake value (SUVmax), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) of 18F-FDG PET/CT were measured. A radioiodine whole body scan was used to determine lesion radioiodine avidity. RESULTS: 69 patients with DTC were enroled in this study, including 37 women (53.6%) and 32 men (46.4%), with a median age of 52 years (11 to 77 years). Regarding the pathological category, papillary thyroid cancer was documented in 50 patients (72.5%), while follicular and poorly differentiated thyroid cancer were found in 12 patients (17.4%) and seven patients (10.1%), respectively. Distant metastases were observed in 27 (39.1%) patients; 34 (49.3%) were classified as stage I, 16 (23.2%) as stage II, and 3 (4.3%) and 16 (23.2%) patients in stages III and IV, respectively. LDHA expression levels were correlated with Glut3 expression levels (r = 0.395, P = 0.003) and SUVmax (r = 0.408, P = 0.002). The median LDHA expression and lesion SUVmax of the RAI avidity group were lower than those of the non-RAI avidity group (200 vs. 285, P = 0.036; 3.06 vs. 8.38, P = 0.038, respectively). Elevated SUVmax (P = 0.004), MTV (P = 0.014), TLG (P = 0.001) and LDHA expression (P = 0.048) led to shorter time to progression (TTP); Cox regression analysis revealed that TLG (HR: 4.773, P = 0.047) was an independent prognostic factor of TTP. CONCLUSION: Elevated LDHA is correlated with increased glucose metabolism, decreased radioiodine avidity, and accelerated disease progression. Moreover, 18F-FDG PET/CT acting as "in vivo pathology" is an excellent predictor of DTC prognosis.

68Ga-FAPI-04 positron emission tomography/CT and laparoscopy for the diagnosis of occult peritoneal metastasis in newly diagnosed locally advanced gastric cancer: study protocol of a single-centre prospective cohort study.

INTRODUCTION: Accurate baseline clinical staging is critical to inform treatment decision-making for patients with gastric cancers. Peritoneal metastasis (PM) is the most common form of metastasis in gastric cancer and mainly diagnosed by diagnostic laparoscopy and peritoneal lavage evaluation. However, diagnostic laparoscopy is invasive and less cost-effective. It is urgent to develop a safe, fast and non-invasive functional imaging method to verify the peritoneal metastasis of gastric cancer. The aim of our study was to evaluate the proportion of patients in whom 68Ga-FAPI-04 positron emission tomography/CT (PET/CT) led to a change in treatment strategy and to assess the diagnostic accuracy of 68Ga-FAPI-04 PET/CT for the detection of occult peritoneal metastasis compared with laparoscopic exploration. METHODS AND ANALYSIS: In this single-centre, prospective diagnostic test accuracy study, a total of 48 patients with locally advanced gastric or gastro-oesophageal junction adenocarcinoma (cT4a-b, N0-3, M0, based on CT images) who are considering radical tumour surgery will be recruited. All participants will undergo 68Ga-FAPI-04 PET/CT before the initiation of laparoscopic exploration. The primary outcome is the proportion of patients with occult peritoneal metastatic lesions detected by 68Ga-FAPI-04 PET/CT, leading to a change in therapy strategy. The secondary outcomes include the diagnostic performance of 68Ga-FAPI-04 PET/CT for occult peritoneal metastasis, including sensitivity, specificity, accuracy, positive predictive value and negative predictive value. ETHICS AND DISSEMINATION: The study protocol was approved by the Ethics Committee of West China Hospital, Sichuan University (2022-1484). Study results will be presented at public and scientific conferences and in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ChiCTR2300067591.

Surufatinib combined with transarterial embolization versus surufatinib monotherapy in patients with liver metastatic neuroendocrine tumors: Study protocol for a prospective, randomized, controlled trial.

BACKGROUND: More than half of neuroendocrine tumor (NET) patients will experience liver metastasis, and interventional therapy represented by transarterial embolization (TAE) is the main local treatment method. Surufatinib is recommended as a standard systemic treatment for advanced NETs. The efficacy and safety of surufatinib combined with TAE in the treatment of liver metastasis are undetermined. This study was conducted to compare the clinical outcome of surufatinib combined with TAE versus surufatinib monotherapy in liver metastatic NETs. METHODS: This is a prospective, multicenter, open-label, and randomized controlled trial. Patients diagnosed with liver metastatic NETs will be enrolled. Participants are randomly assigned in a 1:1 ratio to either the experimental group or the control group. Patients will be treated with surufatinib plus TAE in the experimental group, while patients in the control group will receive surufatinib monotherapy. The primary endpoint is progression-free survival (PFS) assessed by a blinded independent image review committee (BIIRC). The secondary endpoints are investigator-assessed PFS, liver-specific objective response rate (ORR), objective response rate (ORR), disease control rate (DCR), overall survival (OS), and incidence of adverse events. DISCUSSION: This is the first prospective study to investigate the efficacy of surufatinib combined with TAE. We expect this trial to propose a new and effective treatment strategy for liver metastatic NETs.

Comparison of 68Ga-FAPI-04 and 18F-FDG PET/CT in Fumarate Hydratase-Deficient Renal Cell Carcinoma: A Prospective and Single-Center Study.

PURPOSE: Fumarate hydratase-deficient renal cell cancer (FHRCC) is a rare and aggressive form of renal cell carcinoma. The diagnostic value of 68Ga-FAPI PET/CT for FHRCC remains unexplored. Therefore, we compared the potential value of 68Ga-FAPI-04 and 18F-FDG PET/CT in FHRCC. PATIENTS AND METHODS: Patients with FHRCC underwent 68Ga-FAPI-04 and 18F-FDG PET/CT from May 2022 to December 2023. The SUVmax and tumor-to-liver ratio (TLR) of both tracers were compared using the Wilcoxon signed rank test. RESULTS: Eleven patients with 83 lesions were enrolled. The rate of 18F-FDG PET/CT in detecting lesions was higher than that of 68Ga-FAPI-04 PET/CT: primary tumors: 75.0% (6/8) versus 50.0% (4/8); lymph nodes: 94.9% (37/39) versus 89.7% (35/39); and bone lesions: 100.0% (21/21) versus 90.5% (19/21). The median SUVmax of primary and metastatic lesions on 18F-FDG PET/CT was comparable to 68Ga-FAPI-04 PET/CT in semiquantitative analysis (primary lesions: 13.86 vs 16.35, P = 1.000; lymph nodes: 10.04 vs 9.33, P = 0.517; bone lesions: 13.49 vs 9.84, P = 0.107; visceral lesions: 8.54 vs 4.20, P = 0.056). However, the median TLRs of primary and metastatic lesions on 68Ga-FAPI-04 PET/CT were higher than that of 18F-FDG PET/CT (primary lesions: 30.44 vs 5.41, P = 0.010; lymph nodes: 17.71 vs 3.95, P = 0.000; bone lesions: 15.94 vs 5.21, P = 0.000; visceral lesions: 9.26 vs 3.44, P = 0.003). CONCLUSIONS: 18F-FDG PET/CT detected more primary and metastatic FHRCC lesions than 68Ga-FAPI-04 PET/CT. However, the higher TLR in FHRCC on 68Ga-FAPI-04 PET/CT may indicate therapeutic potential in targeting fibroblast activation protein in FHRCC.

Heterogeneous Uptake of 68 Ga-DOTATATE and 18 F-FDG in Initial Diagnosed Neuroendocrine Tumors Patients : Which Patients Are Suitable for Dual-Tracer PET Imaging?

PURPOSE: This study was designed to assess the uptake heterogeneity in neuroendocrine tumor (NET) patients at initial diagnosis with dual-tracer PET imaging and the staging changes and prognostic value it brings to explore the indication of the use of dual-tracer PET. METHODS: Fifty-one newly diagnosed patients with pathologically confirmed NET who underwent 18 F-FDG and 68 Ga-DOTATATE PET imaging between January 2020 and September 2022 were enrolled. Dual-tracer uptake patterns were classified into 3 groups: A. 68 Ga-DOTATATE positive and 18 F-FDG negative, B. 68 Ga-DOTATATE positive and 18 F-FDG positive, and C. 68 Ga-DOTATATE negative and 18 F-FDG positive. Descriptive statistics were used to evaluate the heterogeneity of dual-tracer uptake patterns among different grading (G) groups, between primary and metastatic lesions, and staging changes. Moreover, dual-tracer uptake patterns, grade, age, sex, and stage were compared with progression-free survival (PFS) by Cox regression. RESULTS: In the different G groups, none of the patients with dual-tracer uptake pattern A had grade 3 histology, but 57% of patients with grade 1 disease had FDG avidity (25% of them resulting in dual-tracer uptake pattern C). Patients with no metastasis were well differentiated, but one of them presented with dual-tracer uptake pattern C. Different uptake patterns were also observed between primary and metastatic lesions, particularly 44% of patients with dual-tracer uptake pattern A of primary with FDG avidity of metastases. Moreover, 9 (17.6%) had new lesions detected by additional 18 F-FDG PET imaging, and 3 of them (5.9%) had clinical stage changed accordingly. The Cox regression test showed that the dual-tracer uptake patterns were significantly correlated with PFS by univariate and multivariate analyses ( P = 0.026 and 0.039, respectively), whereas the grade and stage did not correlate with survival (all P >0.05). CONCLUSION: The current study has proven the uptake heterogeneity of the NET at initial diagnosis and demonstrated the staging and prognostic value of dual-tracer PET imaging. Our preliminary results have confirmed the importance of dual-tracer imaging modalities and concluded that dual-tracer PET imaging could be considered as prognostic tool for all patients with an initial diagnosis of NET.