Propensity score analysis of 18-FDG PET/CT-enhanced staging in patients undergoing surgery for esophageal cancer.

PURPOSE: PET/CT is now integral to the staging pathway for potentially curable esophageal cancer (EC), primarily to identify distant metastases undetected by computed tomography. The aim of this study was to analyze the effect of PET/CT introduction on survival and assess patterns of recurrence after esophagectomy. METHODS: A longitudinal cohort of EC patients staged between 1998 and 2016 were considered for inclusion. After co-variate adjustment using propensity scoring, a cohort of 496 patients (273 pre-PET/CT and 223 post-PET/CT) who underwent esophagectomy [median age 63 years (31-80), 395 males, 425 adenocarcinomas, 71 squamous cell carcinomas, 325 neoadjuvant therapy] were included. The primary outcome measure was overall survival (OS) based on intention to treat. RESULTS: Three-year OS pre-PET/CT was 42.5% compared with 57.8% post-PET/CT (Chi2 6.571, df 1, p = 0.004). On multivariable analysis, pT stage (HR 1.496 [95% CI 1.28-1.75], p < 0.0001), pN stage (HR 1.114 [95% CI 1.04-1.19], p = 0.001) and PET/CT staging (HR 0.688 [95% CI 0.53-0.89] p = 0.004) were independently associated with OS. Recurrent cancer was observed in 125 patients (51.4%) pre-PET/CT, compared with 74 patients post-PET/CT (37.8%, p = 0.004), and was less likely to be distant recurrence after PET/CT introduction (39.5 vs. 27.0%, p = 0.006). CONCLUSIONS: Enhanced PET/CT staging is an important modality and independent factor associated with improved survival in patients undergoing esophagectomy for cancer.

Additional value of EUS in oesophageal cancer patients staged N0 on PET/CT: validation of a prognostic model.

BACKGROUND: Lymph node metastases are a major prognostic indicator in oesophageal cancer. Radiological staging largely influences treatment decisions and is becoming more reliant on PET and CT. However, the sensitivity of these modalities is suboptimal and is known to under-stage disease. The primary aim of this study was to validate a published prognostic model in oesophageal cancer patients staged N0 with PET/CT, which showed that EUS nodal status was an independent predictor of survival. The secondary aim was to assess the prognostic significance of pathological lymph node metastases in this cohort. METHODS: An independent validation cohort included 139 consecutive patients from a regional upper gastrointestinal cancer network staged N0 with PET/CT between 1st January 2013 and 31st June 2015. Replicating the original study, two Cox regression models were produced: one included EUS T-stage and EUS N-stage, and one included EUS T-stage and EUS N0 versus N+. The primary outcome of the prognostic model was overall survival (OS). Kaplan-Meier analysis assessed differences in OS between pathological node-negative (pN0) and node-positive (pN+) groups. A p value of < 0.05 was considered statistically significant. RESULTS: The mean OS of the validation cohort was 29.8 months (95% CI 27.1-35.2). EUS T-stage was significantly and independently associated with OS in both models (p = 0.011 and p = 0.012, respectively). EUS N-stage and EUS N0 versus N+ were not significantly associated with OS (p = 0.553 and p = 0.359, respectively). There was a significant difference in OS between pN0 and pN+ groups (χ2 13.315, df 1, p < 0.001). CONCLUSION: Lymph node metastases have a significant detrimental effect on OS. This validation study did not replicate the results of the developed prognostic model but the continued benefit of EUS in patients staged N0 with PET/CT was demonstrated. EUS remains a valuable component of a multi-modality approach to oesophageal cancer staging.

Accuracy of contemporary oesophageal cancer lymph node staging with radiological-pathological correlation.

AIM: To evaluate the accuracy of contemporary N-staging and provide radiological-pathological correlation in patients with lymph node metastases (LNMs) that were radiologically staged N0. MATERIALS AND METHODS: One hundred and twelve patients were included who underwent surgery alone (n=41) or neoadjuvant therapy (n=71) between October 2010 and December 2015. Contrast-enhanced computed tomography (CECT), endoscopic ultrasound (EUS), and combined positron-emission tomography (PET) and CT N-stage were compared to pathological N-stage [node-negative (N0) versus node-positive (N+) groups]. Fifty LNMs from 15 patients preoperatively staged as N0 were measured and the maximum size recorded. RESULTS: Accuracy, sensitivity, and specificity of N0 versus N+ disease with CECT, EUS, and PET/CT was 54.5%, 39.7% and 77.3%, 55.4%, 42.6% and 75%, and 57.1% 35.3%, and 90.9%, respectively. All techniques were more likely to under-stage nodal disease; CECT (X2 32.890, df=1, p<0.001), EUS (X2 28.471, df=1, p<0.001), and PET/CT (X2 50.790, df=1, p<0.001). PET/CT was more likely to under-stage nodal disease than EUS (p=0.031). Median LNM size was 3 mm, with 41 (82%) of LNMs measuring <6 mm and 22 (44%) classified as micro-metastases (≤2 mm). CONCLUSION: This study has demonstrated poor N-staging accuracy in the modern era of radiological staging. Eighty-two percent of LNMs measured <6 mm, making direct identification extremely challenging on medical imaging. Future research should focus on investigating and developing alternative surrogate markers to predict the likelihood of LNMs.

FDG PET-CT imaging of therapeutic response in granulomatous lymphocytic interstitial lung disease (GLILD) in common variable immunodeficiency (CVID).

Common variable immunodeficiency (CVID) is the most common severe adult primary immunodeficiency and is characterized by a failure to produce antibodies leading to recurrent predominantly sinopulmonary infections. Improvements in the prevention and treatment of infection with immunoglobulin replacement and antibiotics have resulted in malignancy, autoimmune, inflammatory and lymphoproliferative disorders emerging as major clinical challenges in the management of patients who have CVID. In a proportion of CVID patients, inflammation manifests as granulomas that frequently involve the lungs, lymph nodes, spleen and liver and may affect almost any organ. Granulomatous lymphocytic interstitial lung disease (GLILD) is associated with a worse outcome. Its underlying pathogenic mechanisms are poorly understood and there is limited evidence to inform how best to monitor, treat or select patients to treat. We describe the use of combined 2-[(18)F]-fluoro-2-deoxy-d-glucose positron emission tomography and computed tomography (FDG PET-CT) scanning for the assessment and monitoring of response to treatment in a patient with GLILD. This enabled a synergistic combination of functional and anatomical imaging in GLILD and demonstrated a widespread and high level of metabolic activity in the lungs and lymph nodes. Following treatment with rituximab and mycophenolate there was almost complete resolution of the previously identified high metabolic activity alongside significant normalization in lymph node size and lung architecture. The results support the view that GLILD represents one facet of a multi-systemic metabolically highly active lymphoproliferative disorder and suggests potential utility of this imaging modality in this subset of patients with CVID.

N-staging of oesophageal and junctional carcinoma: is there still a role for EUS in patients staged N0 at PET/CT?

AIM: To assess whether separate endoscopic ultrasound (EUS) lymph node (N)-staging is still of prognostic value in those staged node negative (N0) at combined positron-emission tomography/computed tomography (PET/CT) in patients with oesophageal cancer (OC). MATERIALS AND METHODS: One hundred and seventeen consecutive patients [median age 67 years; 88 male; 98 cases of adenocarcinoma, 19 cases of squamous cell carcinoma (SCC)] staged as N0 at PET/CT underwent EUS to record tumour (T)- and N-stage. The patients were subsequently separated into two groups: EUS N0 (n = 78) and EUS N+ (n = 39). Survival analysis using Kaplan-Meier and Cox's proportional hazard methods was performed. Primary outcome was overall survival from diagnosis. RESULTS: EUS N-stage and EUS N0 versus EUS N+ (p = 0.005 and p = 0.001, respectively) were found to be significantly and independently associated with survival in two models of multivariate analysis, in patients staged N0 at PET/CT. EUS T-stage was significantly associated with survival on univariate analysis. CONCLUSION: EUS N-staging still has prognostic value in patients staged N0 at PET/CT. There is a significant difference in survival between EUS N0 and positive nodal EUS status in those staged N0 at PET/CT, suggesting PET/CT is unreliable for local staging. PET/CT and EUS continue to have complimentary roles in OC staging.

Feasibility study of FDG PET/CT-derived primary tumour glycolysis as a prognostic indicator of survival in patients with non-small-cell lung cancer.

AIM: To assess the feasibility and prognostic value of measuring total lesion glycolysis of the primary tumour (TLG(primary)) using combined 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography/computed tomography (PET/CT) in patients with proven or suspected non-small-cell lung cancer (NSCLC) in the routine diagnostic setting. MATERIALS AND METHODS: At the All wales Research and Diagnostic Positron Emission Tomography Centre in Cardiff (PETIC), in the calendar year 2011, 288 consecutive patients were identified with a single pulmonary mass in whom NSCLC was confirmed or clinically diagnosed following multidisciplinary team review. In a retrospective analysis, for each patient the PET-derived volume of the primary tumour and SUVMEAN was calculated using adaptive thresholds of 40% and 50% of the SUVMAX of the primary tumour. The TLG(primary) (calculated by volume x SUVMEAN) was calculated at these two thresholds and was used to predict survival in a multivariate analysis with TNM (tumour, node, metastasis) stage, age, sex, and SUV(MAX). The primary endpoint was overall survival over a minimum follow-up of at least 7 months. RESULTS: In virtually every case, the primary tumour could be measured using the automated software with minimal use of manual adjustments. In multivariate analysis, TNM clinical stage, log(TLG(primary)) and sex were independent predictors of overall survival. CONCLUSION: Measurements of primary tumour total lesion glycolysis are simple to perform and provide additional prognostic information over and above that provided by TNM staging.

Prognostic significance of 18-FDG PET/CT and EUS-defined tumour characteristics in patients with oesophageal cancer.

AIM: To determine the correlation between 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography/computed tomography (PET/CT) defined maximum standardized uptake value (SUVmax) and endoluminal ultrasound-defined tumour volume (EDTV) in patients with oesophageal cancer (OC) and their relative prognostic significance. MATERIALS AND METHODS: One hundred and eighty-five consecutive patients with OC were staged using CT, endoscopic ultrasound (EUS), and PET/CT. The maximum potential EDTV was calculated (πr(2)L, where r = tumour thickness and L = total length of disease including proximal and distal lymph node metastases). Primary outcome measure was survival from diagnosis. RESULTS: Ninety-one percent of patients (168/185) had FDG-avid tumours on PET/CT. SUVmax correlated positively and significantly with EDTV (Spearman's rho = 0.339, p = 0.001). On univariate analysis, survival was inversely related to the PET/CT lymph node metastasis count (LNMC, p = 0.015), EUS N stage (p = 0.002), EDTV (<48 cm(3), p = 0.001), EUS total length of disease (p = 0.001), SUVmax (p = 0.002), PET/CT N stage (p < 0.0001), and EUS LNMC (p < 0.0001). On multivariate analysis two factors were significantly and independently associated with survival: EDTV (HR, 3.118; 95% CI: 1.357-7.167; p = 0.007), and PET/CT N stage (HR, 0.496; 95% CI: 0.084-1.577; p = 0.022). CONCLUSION: EDTV and PET/CT N stage were important predictors of survival and further research is needed to identify critical prognostic values.

Multimodality imaging of exuberant mitral annular calcification in a patient presenting with transient ischaemic attack.

We report an unusual case of calcification of mitral valve annulus imaged with multiple non-invasive modalities in a patient who suffered a transient ischaemic attack, probably from thrombus overlying the mitral annular calcification. Both this mode of presentation and the imaging features of the annular calcification were relatively unusual, and the images obtained are remarkably clear and diagnostic.

Liver X receptor inhibits the synthesis and secretion of apolipoprotein A1 by human liver-derived cells.

The liver X receptor (LXR) agonist TO901317 inhibited the synthesis of apolipoprotein A1 (apo A1) by human liver-derived cells, including the formation of lipid-poor, prebeta-migrating high-density lipoprotein (HDL). Despite activation of the lipid transporter ABCA1 under these conditions, cellular efflux of PL and cholesterol from liver cells was also reduced. By assaying transcription from full-length and truncated promoters and by site-directed mutagenesis, the effect of LXR and its ligand was localized to a binding site for hepatic nuclear factor-4 (HNF4) in the proximal apo A1 promoter (-132/-119 bp). Chromatin immunoprecipitation analysis of apo A1 transcription complexes from control and ligand-activated cells showed an increase in the binding of reported apo A1 transcriptional inhibitor COUP-TF, which competes with HNF4 for DNA binding. It also identified LXR in the apo A1 transcription complex of TO901317-treated cells. Displacement of HNF4 from the -132/-119 bp promoter DNA sequence in the presence of TO901317 was confirmed by gel shift analysis. These data indicate that LXR can be a significant negative regulator of apo A1 transcription and HDL synthesis.

Membrane cholesterol and the regulation of signal transduction.

The plasma membrane of mammalian cells consists of microdomains differing in lipid and protein composition. Two distinct classes of cholesterol/sphingolipid microdomain (caveolae and lipid rafts) are assembly points for transmembrane signalling complexes. Recent evidence suggests that transient changes in cholesterol content may be important in regulating signal transduction.

Expression of p53, pRB, and p16 in lung tumours: a validation study on tissue microarrays.

Tissue microarrays have been created from 326 lung tumours, including 173 squamous cell carcinomas (SCCs) and 132 adenocarcinomas (ADs). In order to evaluate the usefulness of this microarray series, the expression of p53, p16, and Rb proteins was compared by immunohistochemistry on both the tissue microarrays and the corresponding whole sections for all 326 tumours. The presence of replicate punches improved both the yield and the concordance of data relative to the whole section results, so that the consensus score from the replicates agreed with the whole section result in more than 90% of informative tumours. The large number of tumours in this series also allowed significant differences in protein expression patterns to be detected between SCC and AD, the major subtypes of non-small cell lung carcinoma (NSCLC). SCC had higher levels of p53 staining (67% vs 52% in AD) and substantially increased p16 loss (SCC 75%, AD 53%) combined with greater retention of pRB expression (SCC 86% vs 67% in AD). The strong inverse correlation between p16 and pRB seen in SCC was essentially absent in AD. This study represents the largest single immunohistochemical survey of protein expression for p53, p16, and RB in NSCLCs.

Sterol efflux to apolipoprotein A-I originates from caveolin-rich microdomains and potentiates PDGF-dependent protein kinase activity.

The kinetics of sterol efflux from human aortic smooth muscle cells equilibrated with a [(3)H]benzophenone-modified photoactivable free cholesterol analogue ((3)H-FCBP) did not differ significantly from those labeled with free cholesterol ((3)H-FC). Trypsin digestion of caveolin cross-linked by photoactivation of FCBP led to association of radiolabel in a single low molecular weight fraction, indicating relative structural homogeneity of caveolin-bound sterol. These findings were used to investigate the organization of sterols in caveolae and the ability of these domains to transfer sterols to apolipoprotein A-I (apo A-I), the major protein of human plasma high-density lipoproteins (HDL). During long-term (4-5 h) incubation with apo A-I, caveolin-associated (3)H-FC and (3)H-FCBP decreased, in parallel with an increase in apo A-I-associated sterol. Assay of caveolin-associated labeled sterols indicated that caveolae were a major source of sterol lost from the cells during HDL formation. Short-term changes of sterol distribution in caveolae were assayed using platelet-derived growth factor (PDGF). PDGF was without effect on FC efflux in the absence of apo A-I, but when apo A-I was present, PDGF increased FC efflux approximately 3-fold beyond the efflux rate catalyzed by apo A-I alone. At the same time, caveolin-associated FC decreased, and PDGF-dependent protein kinase activity was stimulated. Parallel results were obtained with (3)H-FCBP-equilibrated cells, in which apo A-I potentiated a PDGF-mediated reduction of radiolabel cross-linked to caveolin following photoactivation. These results suggest that sterols within caveolae are mobile and selectively transferred to apo A-I. They also suggest a novel role for sterol efflux in amplifying PDGF-mediated signal transduction.

Cellular cholesterol efflux.

Efflux of free cholesterol (FC) continues even when cellular FC mass is unchanged. This reflects a recirculation of preformed FC between cells and extracellular fluids which has multiple functions in cell biology including receptor recycling and signaling as well as cellular FC homeostasis. Total FC efflux is heterogeneous. Simple diffusion to mature high density lipoprotein (HDL), mainly via albumin as intermediate, initiates FC net transport driven by plasma lecithin:cholesterol acyltransferase activity. A second major efflux component reflects protein-facilitated transport from cell surface domains (caveolae, rafts) driven by FC binding to lipid-poor, pre-beta-migrating HDL (pre-beta-HDL). Facilitated efflux from caveolae, unlike simple diffusion, is highly regulated. Neither ABC1 (the protein defective in Tangier disease) nor other ATP-dependent transporters now appear likely to contribute directly to FC efflux. Their role is limited to the initial formation of a particle precursor to circulating pre-beta-HDL, which recycles without further lipid input from ATP-dependent transporter proteins. Lipid-free apolipoprotein A-I, previously considered a surrogate for pre-beta-HDL, has a reactivity much lower than that of native lipoprotein FC acceptors.

Caveolae and intracellular trafficking of cholesterol.

Caveolae, free cholesterol (FC)-rich microdomains of the plasma membrane, are both a terminus for the intracellular transit of newly synthesized and recycling cellular FC, and a site for FC efflux to the extracellular medium. The same domains play key roles as locations for the assembly of signaling complexes and for the endocytosis of selected ligands. Caveolin, the major structural protein of caveolae, plays a regulatory role in growth, the cell cycle, and cell adhesion. Each of these functions is FC-dependent. Caveolae appear to act as both sensors and regulators of cellular FC content, and in this way mediate an array of membrane-dependent cell functions.

A new microbial barrier test for porous medical packaging materials.

A reproducible, quick and easy-to-use test has been developed for routine evaluation and control of packaging materials.

Cholesterol and caveolae: structural and functional relationships.

Caveolae are free cholesterol (FC)- and sphingolipid-rich surface microdomains abundant in most peripheral cells. Caveolin, a FC binding protein, is a major structural element of these domains. Caveolae serve as portals to regulate cellular FC homeostasis, possibly via their association with ancillary proteins including scavenger receptor B1. The FC content of caveolae regulates the transmission of both extracellular receptor-mediated and endogenous signal transduction via changes in the composition of caveolin-associated complexes of signaling intermediates. By controlling surface FC content, reporting membrane changes by signal transduction to the nucleus, and regulating signal traffic in response to extracellular stimuli, caveolae exert a multifaceted influence on cell physiology including growth and cell division, adhesion, and hormonal response. Cell surface lipid 'rafts' may assume many of the functions of caveolae in cells with low levels of caveolin.

A two-step mechanism for free cholesterol and phospholipid efflux from human vascular cells to apolipoprotein A-1.

Smooth muscle and endothelial cells in vivo are quiescent yet exposed to high levels of lipoprotein lipids. Phospholipid (PL) and free cholesterol (FC) efflux maintain homeostasis. Smooth muscle cells (SMC) expressed high levels of ABC-1 transporter mRNA, and glyburide-dependent PL and FC efflux to apolipoprotein A-1 (apo A-1), the major protein of high-density lipoprotein. FC efflux was inhibited by vanadate and okadaic acid, while PL efflux was not. Phosphatidylcholine was the major PL transferred by both cell types. Stimulation of phosphatidylserine efflux, redistributed within the membrane by this transporter, was only minimally increased. Umbilical vein and aortic endothelial cells expressed little ABC-1 mRNA, nor did these cells promote either PL or FC efflux in response to the presence of apo A-1. To investigate the mechanism of ABC-1-dependent lipid efflux from these cells, apo A-1 was preincubated in the presence of unlabeled SMC or fibroblasts, and the conditioned medium was then transferred to endothelial cells. This medium catalyzed the efflux of FC but not of PL from endothelial cells. Such FC efflux was resistant to glyburide but inhibited by okadaic acid and vanadate. The data suggest that ABC-1-dependent PL efflux precedes FC efflux to apo A-1 and that the complex of apo A-1 and PL is a much better acceptor of FC than apo A-1 itself. Inhibition of FC but not PL efflux by vanadate and okadaic acid suggests these transfers involve different mechanisms.

The evolution of loss of heterozygosity on chromosome 17 during the progression to barrett's adenocarcinoma involves a unique combination of target sites in individual specimens.

We have previously identified thirteen common minimally deleted regions (MRs) on chromosome 17 in twelve Barrett's esophageal adenocarcinoma (BOA) specimens using 41 precisely mapped microsatellite markers (Dunn et al., Oncogene, 17: 987-993, 1999). The aim of the present study has been to identify the earliest sites of loss on this chromosome that arise and persist during the progression to BOA. This has been undertaken by the analysis of multiple carefully microdissected tissue samples from each of five esophagectomy specimens, several of which contained identifiable premalignant tissue. Our data demonstrate a stepwise accumulation of loss in each analyzed specimen, consistent with a single clonal pathway in four specimens and several coexisting pathways in one specimen. Several clonal anomalies (loss preceding heterozygosity and variable intrasample degrees of loss at different markers) were also observed. Within extensively deleted regions of the tumor (seen in three specimens), small deletions were detected in premalignant tissue, predominantly at the site of our identified MRs, and these losses were seen to expand and merge during the progression to BOA. Clonal losses at MRs were first detected in tissue showing early changes histologically, including Barrett's intestinal metaplasia and intermediate-grade dysplasia. Our results provide further support for many of the MRs we have previously identified, thereby adding to evidence for the existence of multiple novel cancer-associated genes on chromosome 17 involved in the development of BOA.

Packaging and the environment: a regulation update.

This article reports on the progress that is being made on standards and associated documents to support the Packaging and Packaging Waste Directive. Potential revisions are also discussed.