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To determine the prognostic and predictive value of early metabolic response assessed by a change in standardized uptake value (SUV) on interim 18F-FDG PET in patients with esophageal cancer undergoing neoadjuvant chemoradiotherapy. PubMed and Embase were searched up until 10 September, 2020, for studies evaluating a change in SUV on interim 18F-FDG PET for predicting a pathologic response, progression-free survival (PFS), or overall survival (OS) in patients with esophageal cancer. The sensitivity and specificity for predicting a pathologic response were pooled using bivariate and hierarchical summary receiver operating characteristic (HSROC) models. Meta-analytic pooled hazard ratios (HRs) and their 95% confidence intervals (CIs) were derived using a random-effects model. A total of 11 studies (695 patients) were included in the meta-analysis. For nine studies assessing predictive accuracy, the pooled sensitivity and specificity of an early metabolic response for predicting a pathologic response were 0.80 (95% CI 0.61–0.91) and 0.54 (95% CI 0.45–0.63), respectively. The area under the HSROC curve was 0.64 (95% CI 0.60–0.68). Across the nine studies assessing prognostic value, an early metabolic response determined by interim PET showed pooled HRs for predicting PFS and OS of 0.44 (95% CI, 0.30–0.63) and 0.42 (95% CI, 0.31–0.56), respectively. Change in SUV on interim 18F-FDG PET had significant prognostic value and moderate predictive value for a pathologic response in esophageal cancer treated with neoadjuvant chemoradiotherapy. Interim 18F-FDG PET may help prognostic stratification and guide treatment planning in oncologic practice.

To determine the prognostic and predictive value of early metabolic response assessed by a change in standardized uptake value (SUV) on interimPubMed and Embase were searched up until 10 September, 2020, for studies evaluating a change in SUV on interimA total of 11 studies (695 patients) were included in the meta-analysis. For nine studies assessing predictive accuracy, the pooled sensitivity and specificity of an early metabolic response for predicting a pathologic response were 0.80 (95% CI 0.61-0.91) and 0.54 (95% CI 0.45-0.63), respectively. The area under the HSROC curve was 0.64 (95% CI 0.60-0.68). Across the nine studies assessing prognostic value, an early metabolic response determined by interim PET showed pooled HRs for predicting PFS and OS of 0.44 (95% CI, 0.30-0.63) and 0.42 (95% CI, 0.31-0.56), respectively.Change in SUV on interim

Idiopathic pulmonary fibrosis (IPF) is associated with an increased incidence of lung cancer, but patients with IPF often have poor pulmonary function and are vulnerable to pneumothorax and so using an invasive procedure to diagnose a single nodule detected on chest CT risks a critical adverse outcome. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is recognized to be useful for differentiating between benign and malignant solitary pulmonary nodules (SPN) in patients without IPF, but its diagnostic accuracy has not been investigated in patients with IPF. In this study, therefore, we investigated whether 18F-FDG PET/CT is useful for the differential diagnosis of SPNs in patients with IPF. From the IPF patient cohort of our institution, we retrospectively reviewed 55 patients (54 men, 1 woman; age 67.8 ± 7.6 years) with an SPN sized 8–30 mm (mean 18.5 ± 5.7 mm) who underwent chest CT followed by 18F-FDG PET/CT between April 2004 and March 2016. The 18F-FDG uptake of the SPN was analyzed visually and semiquantitatively, and these determinations were compared with the final diagnosis obtained by pathology (n = 52) or imaging follow-up (n = 3). The final diagnoses showed that 41 (75%) of the SPNs were malignant (21 squamous cell carcinomas, 9 adenocarcinomas, 5 small-cell carcinomas, 4 mixed-type carcinomas, 1 large-cell neuroendocrine carcinoma, and 1 sarcoid carcinoma) and 14 (25%) were benign. The determination of malignant SPNs by visual analysis of the PET/CT images had a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 98, 86, 95, and 92%, respectively. The semiquantitative analysis using a maximum standardized uptake value of 2.0 as the cut-off had a sensitivity, specificity, PPV, and NPV of 95, 93, 98, and 87%, respectively. 18F-FDG PET/CT is useful for differentiating benign and malignant SPNs in patients with IPF, as it is for patients without IPF.

We aimed to explore the ability of textural heterogeneity indices determined by (18)F-FDG PET/CT for grading the malignancy of thymic epithelial tumors (TETs).We retrospectively enrolled 47 patients with pathologically proven TETs who underwent pre-treatment (18)F-FDG PET/CT. TETs were classified by pathological results into three subgroups with increasing grades of malignancy: low-risk thymoma (LRT; WHO classification A, AB and B1), high-risk thymoma (B2 and B3), and thymic carcinoma (TC). Using (18)F-FDG PET/CT, we obtained conventional imaging indices including SUVmax and 20 intratumoral heterogeneity indices: i.e., four local-scale indices derived from the neighborhood gray-tone difference matrix (NGTDM), eight regional-scale indices from the gray-level run-length matrix (GLRLM), and eight regional-scale indices from the gray-level size zone matrix (GLSZM). Area under the receiver operating characteristic curve (AUC) was used to demonstrate the abilities of the imaging indices for differentiating subgroups. Multivariable logistic regression analysis was performed to show the independent significance of the textural indices. Combined criteria using optimal cutoff values of the SUVmax and a best-performing heterogeneity index were applied to investigate whether they improved differentiation between the subgroups.Most of the GLRLM and GLSZM indices and the SUVmax showed good or fair discrimination (AUC0.7) with best performance for some of the GLRLM indices and the SUVmax, whereas the NGTDM indices showed relatively inferior performance. The discriminative ability of some of the GLSZM indices was independent from that of SUVmax in multivariate analysis. Combined use of the SUVmax and a GLSZM index improved positive predictive values for LRT and TC.Texture analysis of (18)F-FDG PET/CT scans has the potential to differentiate between TET tumor grades; regional-scale indices from GLRLM and GLSZM perform better than local-scale indices from the NGTDM. The SUVmax and heterogeneity indices may have complementary value in differentiating TET subgroups.

Idiopathic pulmonary fibrosis (IPF) is associated with an increased incidence of lung cancer, but patients with IPF often have poor pulmonary function and are vulnerable to pneumothorax and so using an invasive procedure to diagnose a single nodule detected on chest CT risks a critical adverse outcome.From the IPF patient cohort of our institution, we retrospectively reviewed 55 patients (54 men, 1 woman; age 67.8 ± 7.6 years) with an SPN sized 8-30 mm (mean 18.5 ± 5.7 mm) who underwent chest CT followed byThe final diagnoses showed that 41 (75%) of the SPNs were malignant (21 squamous cell carcinomas, 9 adenocarcinomas, 5 small-cell carcinomas, 4 mixed-type carcinomas, 1 large-cell neuroendocrine carcinoma, and 1 sarcoid carcinoma) and 14 (25%) were benign. The determination of malignant SPNs by visual analysis of the PET/CT images had a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 98, 86, 95, and 92%, respectively. The semiquantitative analysis using a maximum standardized uptake value of 2.0 as the cut-off had a sensitivity, specificity, PPV, and NPV of 95, 93, 98, and 87%, respectively.

The purpose of this study was to investigate the diagnostic performance of postoperative fluorine-18 fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) as a surveillance modality for advanced gastric cancer patients who were asymptomatic and negative by conventional follow-up.We retrospectively collected 46 advanced gastric cancer patients who received approximately 1-year-postoperative (18)F-FDG PET/CT surveillance following curative resection (mean age 60.6 ± 11.5 years). (18)F-FDG PET/CT was interpreted by nuclear medicine physicians who were blind to the clinical information. Final confirmation was determined by clinical follow-up using tumor markers, conventional CT scan, upper gastrointestinal endoscopy and with/without subsequent histopathologic diagnosis.Four patients developed recurrence (8.7 %; 1 local and 3 distant recurrences). For local recurrence, (18)F-FDG PET/CT found four hypermetabolic lesions and one was local recurrence. For distant recurrence, seven hypermetabolic lesions were found in six patients and true-positive was three lesions. False-positive cases were mainly turned out to be physiologic small bowel uptake. Regardless of the recurrence site, the sensitivity, specificity, positive predictive value and negative predictive value of (18)F-FDG PET/CT were 100 % (4/4, 95 % confidence interval (CI) 39.6-100 %), 88.1 % (37/42, 95 % CI 73.6-95.5 %), 44.4 % (4/9, 95 % CI 15.3-77.3 %) and 100 % (37/37, 95 % CI 88.3-100 %), respectively in the patient-based analysis.Our study showed good specificity of postoperative surveillance (18)F-FDG PET/CT for detecting recurrence. Careful caution should be made for interpreting some false-positive hypermetabolic lesions in postoperative (18)F-FDG PET/CT, especially at the local anastomosis site.

Metformin-induced [F-18] fluorodeoxyglucose (FDG) bowel uptake can hinder positron emission tomography/computed tomography (PET/CT) evaluation of the bowel. This study aimed to investigate the segmental bowel uptake of FDG according to metformin discontinuation times up to 72 h. We retrospectively divided 240 diabetic patients into four groups: metformin discontinuation

A diffuse hepatic uptake (DHU) on radioiodine whole-body scans (WBS) after (131)I therapy is caused by (131)I-labeled iodoproteins, particularly (131)I-labeled thyroglobulin (Tg). We hypothesized that the DHU intensity after (131)I therapy might correlate with subsequent serum Tg reduction, suggesting that DHU reflects destruction of functioning thyroid tissue as measured by serum Tg.We retrospectively reviewed the medical records and (131)I WBSs of 47 patients treated with (131)I therapy for distant metastasis from differentiated thyroid cancer (M:F = 15:32, median age 45 years, range 11-74 years). All patients received post-ablative (131)I scans (PAWBS) at first (131)I ablation after total thyroidectomy and post-therapy (131)I scan (PTWBS) at second (131)I therapy. The DHU intensities of the PAWBS and PTWBS were classified into 3 grades: 1, faint; 2, modest; and 3, intense. Serum thyroid-stimulating hormone-stimulated Tg (sTg) levels were measured at the time of each therapy and 1 year after the second (131)I therapy.One year after the second (131)I therapy, 10 patients (21.3%) were in remission and 37 (78.7%) had persistent disease. The DHU intensity on PAWBS correlated with the percentage sTg reduction at the next follow-up point (σ = 0.466, p = 0.0016). The patients with intense DHU on PTWBS tended to have a higher percentage sTg reduction than the other patients, although statistical significances were marginal (Spearman's rank correlation: σ = 0.304, p = 0.054; Kruskal-Wallis test: p = 0.067). In univariate analysis, the DHU grades on PAWBS and the initial sTg levels were significantly different between patients in remission and those with persistent disease (PAWBS: p = 0.022; initial sTg: p = 0.0059). In multivariate logistic regression analysis, after adjusting for initial sTg levels, a DHU grade of 3 on PAWBS was an independent predictor of remission (PAWBS: p = 0.028; initial sTg100 ng/ml: p = 0.043).In patients with iodine-avid distant metastases, intensity of DHU on (131)I post-therapy scan correlated with subsequent percentage serum sTg reduction. Also, intense DHU could be one of the predictors of remission in these patients.