Identifying latent tuberculosis in high-risk populations: systematic review and meta-analysis of test accuracy.

BACKGROUND: The relative accuracy of interferon-gamma release assays (IGRAs) and the tuberculin skin test (TST) in identifying latent tuberculosis infection (LTBI) is uncertain.OBJECTIVE: To perform a systematic review and meta-analysis to compare the sensitivity and specificity of IGRAs and TST for the prediction of progression to clinical tuberculosis (TB).METHODS: We searched electronic databases (e.g., MEDLINE and EMBASE) from December 2009 to September 2018 for prospective studies that followed up individuals who had undergone testing with commercial IGRAs and/or TST but had not received treatment based on the test result. The sensitivity and specificity estimates were pooled using a Bayesian bivariate random-effects model.RESULTS: Twenty-five studies, mostly with moderate to high risk of bias and a mean follow-up time ranging from 1 to 5 years were included. TST (10-15 mm) tended to have lower sensitivity and higher specificity than QuantiFERON® Gold In-Tube, T-SPOT®.TB and TST (5 mm). The evidence did not indicate that any test outperformed the others due to wide and overlapping 95% credible intervals.CONCLUSION: The evidence following individuals who had undergone testing for LTBI and had progressed to clinical TB is sparse. We did not find that IGRAs were superior to TST or vice versa; however, as our findings are based on a small number of studies with methodological limitations and great uncertainty around the pooled estimates, the results should be interpreted with caution.

Short- and long-term clinical outcomes of use of beta-interferon or glatiramer acetate for people with clinically isolated syndrome: a systematic review of randomised controlled trials and network meta-analysis.

BACKGROUND: Beta-interferon (IFN-ß) and glatiramer acetate (GA) have been evaluated in people with clinically isolated syndrome (CIS) with the aim to delay a second clinical attack and a diagnosis of clinically definite multiple sclerosis (CDMS). We systematically reviewed trials evaluating the short- and long-term clinical effectiveness of these drugs in CIS. METHODS: We searched multiple electronic databases. We selected randomised controlled studies (RCTs) conducted in CIS patients and where the interventions were IFN-ß and GA. Main outcomes were time to CDMS, and discontinuation due to adverse events (AE). We compared interventions using random-effect network meta-analyses (NMA). We also reported outcomes from long-term open-label extension (OLE) studies. RESULTS: We identified five primary studies. Four had open-label extensions following double-blind periods comparing outcomes between early vs delayed DMT. Short-term clinical results (double-blind period) showed that all drugs delayed CDMS compared to placebo. Indirect comparisons did not suggest superiority of any one active drug over another. We could not undertake a NMA for discontinuation due to AE. Long-term clinical results (OLE studies) showed that the risk of developing CDMS was consistently reduced across studies after early DMT treatment compared to delayed DMT (HR = 0.64, 95% CI 0.55, 0.74). No data supported the benefit of DMTs in reducing the time to, and magnitude of, disability progression. CONCLUSIONS: Meta-analyses confirmed that IFN-ß and GA delay time to CDMS compared to placebo. In the absence of evidence that early DMTs can reduce disability progression, future research is needed to better identify patients most likely to benefit from long-term DMTs.

Measurement properties of the Haem-A-QoL in haemophilia clinical trials.

INTRODUCTION: Patients with haemophilia on long-acting prophylactic treatment may experience an improvement in health-related quality of life (HRQoL) through reductions in breakthrough bleeds and associated complications, including long-term joint damage, compared with episodic treatment. AIM: This analysis examined clinical trial data to understand the psychometric characteristics (reliability, validity and sensitivity to change over time) of the Haem-A-QoL Questionnaire in adult males with haemophilia. METHODS: Two recent, multinational, Phase 3 clinical trials of new, long-acting factor concentrates (A-LONG: rFVIIIFc; B-LONG: rFIXFc) assessed HRQoL in adolescent and adult males with severe haemophilia A or B respectively. The adults' baseline assessments, via the 46-item Haem-A-QoL Questionnaire, and change over time at the 6-month assessment were used in the psychometric analyses. RESULTS: Internal consistency reliability was adequate (Cronbach's alpha > 0.70) for nine of the 10 Haem-A-QoL domains and for 'Total Score' in both trials at baseline (A-LONG, n = 133; B-LONG, n = 73). At baseline, several Haem-A-QoL domains and 'Total Score' demonstrated known-groups and convergent validity when compared with other trial measures, including the EQ-5D (items and total scores) and joint impairment. Change score correlations (baseline to 28 weeks) between the EQ-5D and the Haem-A-QoL 'Total Score', and 'Physical Health' and 'Feelings' domains were moderate in magnitude (│r│ ≥ 0.33; P < 0.03), demonstrating sensitivity to change for these outcome measures in A-LONG. CONCLUSION: These psychometric analyses provide evidence of the reliability, validity and ability to detect change of the Haem-A-QoL to assess the HRQoL of adult males with severe haemophilia A and B in longitudinal clinical trials.

Changes in health-related quality of life with treatment of longer-acting clotting factors: results in the A-LONG and B-LONG clinical studies.

INTRODUCTION: In haemophilia, prophylactic infusion of replacement factor can result in improvements in health-related quality of life (HRQoL) when compared with episodic treatment. The Haemophilia-specific Quality of Life (Haem-A-QoL) questionnaire assessed HRQoL in adults with severe haemophilia A or B who received prophylactic or episodic treatment with recombinant factor VIII or IX Fc fusion protein (rFVIIIFc or rFIXFc) in the A-LONG or B-LONG clinical studies. AIMS: Understand changes in HRQoL during the A-LONG and B-LONG trials. METHODS: Group-level and individual-level changes over time for the Haem-A-QoL key domains of 'Physical Health' and 'Sports & Leisure,' and 'Total Score' were evaluated in adults through baseline and 6-month HRQoL assessments. Previously determined responder definitions (RDs) were used for evaluating meaningful subject-level HRQoL improvements. RESULTS: The analysis included 67 A-LONG and 51 B-LONG subjects who completed the Haem-A-QoL (baseline and 6 months). While HRQoL improvements were observed among all treatment groups, greater improvements in HRQoL were observed among subjects who received episodic treatment pre-study (and prophylaxis on-study) compared to those who received hyphenate prophylaxis. Applying the RDs for interpreting 6-month changes, 47.4%/33.3% ('Physical Health'), 35.9%/50.0% ('Sports & Leisure') and 23.9%/33.3% ('Total Score') of A-LONG subjects who received individualized or weekly prophylaxis were classified as HRQoL responders. In B-LONG, 69.2%/57.9% ('Physical Health'), 44.4%/56.7% ('Sports & Leisure') and 41.7%/44.1% ('Total Score') of subjects who received individualized or weekly prophylaxis were classified as HRQoL responders. CONCLUSION: Changes in Haem-A-QoL key domains and 'Total Score' suggest that prophylaxis with long-acting rFVIIIFc or rFIXFc resulted in meaningful HRQoL improvements.

Interpreting important health-related quality of life change using the Haem-A-QoL.

The Haemophilia Quality of Life Questionnaire for Adults (Haem-A-QoL) measures health-related quality of life (HRQoL) in adults with haemophilia; however, change score thresholds for identifying individuals experiencing a HRQoL benefit have not been appropriately investigated. The objective of this analysis was to derive appropriate HRQoL responder definitions (RDs) for two Haem-A-QoL domains that reflect key impairments, 'Physical Health' and 'Sports & Leisure,' and the Haem-A-QoL 'Total Score' using anchor- and distribution-based methods. In this analysis, data from adults in A-LONG and B-LONG, two Phase 3 clinical studies of rFVIIIFc in haemophilia A and rFIXFc in haemophilia B, respectively, were used. The anchor-based approach identified Haem-A-QoL changes corresponding to EQ-5D item improvements between baseline and 6 months; the distribution-based methods examined the magnitude at baseline of one-half standard deviation and the standard error of measurement. Through triangulation, the most appropriate RDs were derived. Of the 133 A-LONG and 73 B-LONG subjects with baseline Haem-A-QoL scores, 67 and 51 subjects, respectively, completed the Haem-A-QoL questionnaire at both baseline and 6 months follow-up. Triangulation of anchor- and distribution-based estimates with the observed Haem-A-QoL change scores identified a 10-point reduction in the 'Physical Health' and 'Sports & Leisure' domains, and a 7-point reduction in 'Total Score' as the RD thresholds most indicative of HRQoL benefit. These empirically derived RDs for two key Haem-A-QoL domains and 'Total Score' are reasonable and practical thresholds for identifying subjects with notable improvements in HRQoL, and provides HRQoL RDs that can be used for further analysis and interpretation of data from haemophilia clinical trials.

Evaluating PET-CT in routine surveillance and follow-up after treatment for cervical cancer: a cost-effectiveness analysis.

OBJECTIVE: To undertake a cost-effectiveness analysis that compares positron emission tomography - computed tomography (PET-CT) imaging plus standard practice with standard practice alone in the diagnosis of recurrent or persistent cervical cancer during routine surveillance and follow-up of women who have previously been diagnosed and treated. DESIGN: Model-based economic evaluation using data from a systematic review, supplemented with data from other sources, and taking a UK National Health Service (NHS) perspective. SETTING: Secondary Care in England. POPULATION: Women at least 3 months after the completion of treatment, with either recurrent or persistent cervical cancer. METHODS: A state transition (Markov) model was developed using TreeAge Pro 2011. The structure of the model was informed by the reviews of the trials and clinical input. In the model, two diagnostic strategies were examined. A one-way sensitivity analysis, probabilistic sensitivity analysis, and a value of information analysis were also carried out. MAIN OUTCOME MEASURES: Cost-effectiveness based on incremental cost per quality-adjusted life year (QALY). RESULTS: Adding PET-CT to the current treatment strategy of clinical examination and scanning [magnetic resonance imaging (MRI) and/or CT scan] during the routine surveillance and follow-up of women with recurrent or persistent cervical cancer is significantly more costly, with only a minimal increase in effectiveness. The incremental cost-effectiveness ratio (ICER) for the strategy of PET-CT as an adjunct to the standard treatment strategy that included clinical examination, MRI, and/or CT scan, compared with the usual treatment alone, was over £1 million per QALY. CONCLUSION: The results of the current analysis suggest that use of PET-CT in the diagnosis of recurrent or persistent cervical cancer is not cost-effective. Current guidelines recommending imaging using PET-CT as a diagnostic or surveillance tool need to be reconsidered in light of these results. This study did not specifically investigate the use of PET-CT in women with symptoms and radiological suspicion of recurrence where exenteration was considered. More research in that specific area is required.

Evaluating PET-CT in the detection and management of recurrent cervical cancer: systematic reviews of diagnostic accuracy and subjective elicitation.

BACKGROUND: Positron emission tomography-computed tomography (PET-CT) is recommended to triage women for exenterative surgery and surveillance after treatment for advanced cervical cancer. OBJECTIVE: To evaluate diagnostic accuracy of additional whole body PET-CT compared with CT/magnetic resonance imaging (MRI) alone in women with suspected recurrent/persistent cervical cancer and in asymptomatic women as surveillance. DESIGN: Systematic reviews. Subjective elicitation to supplement diagnostic information. SEARCH STRATEGY/SELECTION CRITERIA/DATA COLLECTION AND ANALYSIS: Searches of electronic databases were performed to June 2013. Studies in women with suspected recurrent/persistent cervical cancer and in asymptomatic women undergoing follow up with sufficient numeric data were included. We calculated sensitivity, specificity and corresponding 95% confidence intervals. Meta-analyses employed a bivariate model that included a random-effects term for between-study variations (CT studies) and univariate random effects meta-analyses (PET-CT studies) for sensitivity and specificity separately. SUBJECTIVE ELICITATION: Prevalence of recurrence and the accuracy of imaging elicited using the allocation of points technique. Coherence of elicited subjective probabilities with estimates in the literature examined. RESULTS: We identified 15 relevant studies; none directly compared additional PET-CT with MRI or CT separately. Most CT and MRI studies used older protocols and the majority did not distinguish between asymptomatic and symptomatic women. Meta-analysis of nine PET-CT studies in mostly symptomatic women showed sensitivity of 94.8 (95% CI 91.2-96.9), and specificity of 86.9% (95% CI 82.2-90.5). The summary estimate of the sensitivity of CT for detection of recurrence was 89.64% (95% CI 81.59-94.41) and specificity was 76% (95% CI 43.68-92.82). Meta-analysis for MRI test accuracy studies was not possible because of clinical heterogeneity. The sensitivity and specificity of MRI in pelvic recurrence varied between 82 and 100% and between 78 and 100%, respectively. Formal statistical comparisons of the accuracy of index tests were not possible. Subjective elicitation provided estimates comparable to the literature. Subjective estimates of the increase in accuracy from the addition of PET-CT were less than elicited increases required to justify the use in PET-CT for surveillance. CONCLUSION: Evidence to support additional PET-CT is scarce, of average quality and does not distinguish between application for surveillance and diagnosis. Guidelines recommending PET-CT in recurrent cervical cancer need to be reconsidered in the light of the existing evidence base.

Positron emission tomography/computerised tomography imaging in detecting and managing recurrent cervical cancer: systematic review of evidence, elicitation of subjective probabilities and economic modelling.

BACKGROUND: Cancer of the uterine cervix is a common cause of mortality in women. After initial treatment women may be symptom free, but the cancer may recur within a few years. It is uncertain whether it is more clinically effective to survey asymptomatic women for signs of recurrence or to await symptoms or signs before using imaging. OBJECTIVES: This project compared the diagnostic accuracy of imaging using positron emission tomography/computerised tomography (PET-CT) with that of imaging using CT or magnetic resonance imaging (MRI) alone and evaluated the cost-effectiveness of adding PET-CT as an adjunct to standard practice. DATA SOURCES: Standard systematic review methods were used to obtain and evaluate relevant test accuracy and effectiveness studies. Databases searched included MEDLINE, EMBASE, Science Citation Index and The Cochrane Library. All databases were searched from inception to May 2010. REVIEW METHODS: Study quality was assessed using appropriately modified Quality Assessment of Diagnostic Accuracy Studies (QUADAS) criteria. Included were any studies of PET-CT, MRI or CT compared with the reference standard of histopathological findings or clinical follow-up in symptomatic women suspected of having recurrent or persistent cervical cancer and in asymptomatic women a minimum of 3 months after completion of primary treatment. Subjective elicitation of expert opinion was used to supplement diagnostic information needed for the economic evaluation. The effectiveness of treatment with chemotherapy, radiotherapy, chemoradiotherapy, radical hysterectomy and pelvic exenteration was systematically reviewed. Meta-analysis was carried out in RevMan 5.1 (The Cochrane Collaboration, The Nordic Cochrane Centre, Copenhagen, Denmark) and Stata version 11 (StataCorp LP, College Station, Texas, USA). A Markov model was developed to compare the relative cost-effectiveness using TreeAge Pro software version 2011 (TreeAge Software Inc., Evanston, IL, USA). RESULTS: For the diagnostic review, a total of 7524 citations were identified, of which 12 test accuracy studies were included in the review: six studies evaluated PET-CT, two evaluated MRI, three evaluated CT and one evaluated both MRI and CT. All studies were small and the majority evaluated imaging in women in whom recurrence was suspected on the basis of symptoms. The PET-CT studies evaluated local and distant recurrence and most used methods similar to current practice, whereas five of the six CT and MRI studies evaluated local recurrence only and not all employed currently used methods. Meta-analysis of PET-CT studies gave a sensitivity of 92.2% [95% confidence interval (CI) 85.1% to 96.0%] and a specificity of 88.1% (95% CI 77.9% to 93.9%). MRI sensitivities and specificities varied between 82% and 100% and between 78% and 100%, respectively, and CT sensitivities and specificities varied between 78% and 93% and between 0% and 95%, respectively. One small study directly compared PET-CT with older imaging methods and showed more true-positives and fewer false-negatives with PET-CT. The subjective elicitation from 21 clinical experts gave test accuracy results for asymptomatic and symptomatic women and the results for symptomatic women were similar to those from the published literature. Their combined opinions also suggested that the mean elicited increase in accuracy from the addition of PET-CT to MRI and/or CT was less than the elicited minimum important difference in accuracy required to justify the routine addition of PET-CT for the investigation of women after completion of primary treatment. For the effectiveness review, a total of 24,943 citations were identified, of which 62 studies were included (chemotherapy, 19 randomised controlled trials; radiotherapy or chemoradiotherapy, 16 case series; radical hysterectomy and pelvic exenteration, 27 case series). None provided the effectiveness of cisplatin monotherapy, the most commonly used chemotherapeutic agent in the NHS, compared with supportive care in a background of other treatment such as radiotherapy in recurrent and persistent cervical cancer. The model results showed that adding PET-CT to the current treatment strategy of clinical examination, MRI and/or CT scan was significantly more costly with only a minimal increase in effectiveness, with incremental cost-effectiveness ratios for all models being > £1M per quality-adjusted life-year (QALY) and the additional cost per additional case of recurrence being in the region of £600,000. LIMITATIONS: There was considerable uncertainty in many of the parameters used because of a lack of good-quality evidence in recurrent or persistent cervical cancer. The evidence on diagnostic and therapeutic impact incorporated in the economic model was poor and there was little information on surveillance of asymptomatic women. CONCLUSIONS: Given the current evidence available, the addition of PET-CT to standard practice was not found to be cost-effective in the diagnosis of recurrent or persistent cervical cancer. However, although probabilistic sensitivity analysis showed that the main conclusion about cost-ineffectiveness of PET-CT was firm given the range of assumptions made, should more reliable information become available on accuracy, therapeutic impact and effectiveness, and the cost of PET-CT reduce, this conclusion may need revision. Current guidelines recommending imaging for diagnosis using expensive methods such as PET-CT need to be reconsidered in the light of the above. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Pulse oximetry as a screening test for congenital heart defects in newborn infants: a test accuracy study with evaluation of acceptability and cost-effectiveness.

BACKGROUND: Screening for congenital heart defects (CHDs) relies on antenatal ultrasound and postnatal clinical examination; however, life-threatening defects often go undetected. OBJECTIVE: To determine the accuracy, acceptability and cost-effectiveness of pulse oximetry as a screening test for CHDs in newborn infants. DESIGN: A test accuracy study determined the accuracy of pulse oximetry. Acceptability of testing to parents was evaluated through a questionnaire, and to staff through focus groups. A decision-analytic model was constructed to assess cost-effectiveness. SETTING: Six UK maternity units. PARTICIPANTS: These were 20,055 asymptomatic newborns at ≥ 35 weeks' gestation, their mothers and health-care staff. INTERVENTIONS: Pulse oximetry was performed prior to discharge from hospital and the results of this index test were compared with a composite reference standard (echocardiography, clinical follow-up and follow-up through interrogation of clinical databases). MAIN OUTCOME MEASURES: Detection of major CHDs - defined as causing death or requiring invasive intervention up to 12 months of age (subdivided into critical CHDs causing death or intervention before 28 days, and serious CHDs causing death or intervention between 1 and 12 months of age); acceptability of testing to parents and staff; and the cost-effectiveness in terms of cost per timely diagnosis. RESULTS: Fifty-three of the 20,055 babies screened had a major CHD (24 critical and 29 serious), a prevalence of 2.6 per 1000 live births. Pulse oximetry had a sensitivity of 75.0% [95% confidence interval (CI) 53.3% to 90.2%] for critical cases and 49.1% (95% CI 35.1% to 63.2%) for all major CHDs. When 23 cases were excluded, in which a CHD was already suspected following antenatal ultrasound, pulse oximetry had a sensitivity of 58.3% (95% CI 27.7% to 84.8%) for critical cases (12 babies) and 28.6% (95% CI 14.6% to 46.3%) for all major CHDs (35 babies). False-positive (FP) results occurred in 1 in 119 babies (0.84%) without major CHDs (specificity 99.2%, 95% CI 99.0% to 99.3%). However, of the 169 FPs, there were six cases of significant but not major CHDs and 40 cases of respiratory or infective illness requiring medical intervention. The prevalence of major CHDs in babies with normal pulse oximetry was 1.4 (95% CI 0.9 to 2.0) per 1000 live births, as 27 babies with major CHDs (6 critical and 21 serious) were missed. Parent and staff participants were predominantly satisfied with screening, perceiving it as an important test to detect ill babies. There was no evidence that mothers given FP results were more anxious after participating than those given true-negative results, although they were less satisfied with the test. White British/Irish mothers were more likely to participate in the study, and were less anxious and more satisfied than those of other ethnicities. The incremental cost-effectiveness ratio of pulse oximetry plus clinical examination compared with examination alone is approximately £24,900 per timely diagnosis in a population in which antenatal screening for CHDs already exists. CONCLUSIONS: Pulse oximetry is a simple, safe, feasible test that is acceptable to parents and staff and adds value to existing screening. It is likely to identify cases of critical CHDs that would otherwise go undetected. It is also likely to be cost-effective given current acceptable thresholds. The detection of other pathologies, such as significant CHDs and respiratory and infective illnesses, is an additional advantage. Other pulse oximetry techniques, such as perfusion index, may enhance detection of aortic obstructive lesions. FUNDING: The National Institute for Health Research Health Technology programme.

Pulse oximetry as a screening test for congenital heart defects in newborn infants: a cost-effectiveness analysis.

OBJECTIVE: To undertake a cost-effectiveness analysis that compares pulse oximetry as an adjunct to clinical examination with clinical examination alone in newborn screening for congenital heart defects (CHDs). DESIGN: Model-based economic evaluation using accuracy and cost data from a primary study supplemented from published sources taking an NHS perspective. SETTING: Six large maternity units in the UK. PATIENTS: 20 055 newborn infants prior to discharge from hospital. INTERVENTION: Pulse oximetry as an adjunct to clinical examination. MAIN OUTCOME MEASURE: Cost effectiveness based on incremental cost per timely diagnosis. RESULTS: Pulse oximetry as an adjunct to clinical examination is twice as costly but provides a timely diagnosis to almost 30 additional cases of CHD per 100 000 live births compared with a modelled strategy of clinical examination alone. The incremental cost-effectiveness ratio for this strategy compared with clinical examination alone is approximately £24 000 per case of timely diagnosis in a population in which antenatal screening for CHDs already exists. The probabilistic sensitivity analysis suggests that at a willingness-to-pay (WTP) threshold of £100 000, the probability of 'pulse oximetry as an adjunct to clinical examination' being cost effective is more than 90%. Such a WTP threshold is plausible if a newborn with timely diagnosis of a CHD gained just five quality-adjusted life years, even when treatment costs are taken into consideration. CONCLUSION: Pulse oximetry as an adjunct to current routine practice of clinical examination alone is likely to be considered a cost-effective strategy in the light of currently accepted thresholds.

An economic evaluation of positron emission tomography (PET) and positron emission tomography/computed tomography (PET/CT) for the diagnosis of breast cancer recurrence.

OBJECTIVES: To review the published economic studies that have evaluated positron emission tomography/computed tomography (PET/CT) in the treatment of recurrent breast cancer, and to develop and carry out a model-based economic evaluation to investigate the relative cost-effectiveness of PET/CT to detect breast cancer recurrence compared with conventional work-up. DATA SOURCES: A systematic review of economic and diagnostic evidence for PET/CT in diagnosis of breast cancer recurrence. The original databases searched include MEDLINE (Ovid) (1950 to week 5 May 2009), EMBASE (Ovid) (1980 to 2009 week 22) and the NHS Economic Evaluation Database. An updated search was conducted for each database from May 2009 to week 4 April 2010. METHODS: A decision tree was developed in TREEAGE software (TreeAge Software Inc., Williamstown, MA, USA). The relevant data on accuracy, sensitivity and specificity of each diagnostic test were linked in the model, to costs and the primary outcome measure, cost per quality-adjusted life-year (QALY). The model estimated the mean cost associated with each diagnostic procedure and assumed that patients entering the model were aged 50-75 years. The results of the cost-effectiveness analysis are presented in terms of the incremental cost-effectiveness ratios (ICERs). RESULTS: The ICER for the strategy of PET compared with conventional work-up was estimated at £29,300 per QALY; the ICER for PET/CT compared with PET was £ 31,000 per QALY; and the ICER for PET/CT combined with conventional work-up versus PET/CT was £ 42,100. Clearly, for each additional diagnostic test that is added to PET, the more expensive the package becomes, but also the more effective it becomes in terms of QALYs gained. The probabilistic sensitivity analysis shows that at a willingness-to-pay threshold of £ 20,000 per QALY, conventional work-up is the preferred option. LIMITATIONS: Only data from indirect comparisons are available from the accuracy review, and there is some uncertainty about whether the data defining the accuracy of PET/CT present its use as a replacement or as an adjunct to conventional work-up. CONCLUSIONS: Based on the current model and given the limitations that are apparent in terms of limited availability of data, the result of the current analysis suggests that the use of PET/CT in the diagnosis of recurrent breast cancer in every woman suspected of having a recurrence is unlikely to be cost-effective given the current willingness-to-pay thresholds that are accepted in the UK by decision-making bodies such as the National Institute for Health and Clinical Excellence. Our modelling suggests that conventional work-up could be the most cost-effective diagnostic strategy given current data. Future studies need to secure robust cost data that can be verified from more than one source for the diagnostic tests involved in PET and PET/CT. Reliable and verifiable data on quality of life associated with this clinical condition are also crucial. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Loss of responsiveness to IGF-I in cells with reduced cathepsin L expression levels.

The lysosomal cysteine proteinase cathepsin L is involved in proteolytic processing of internalized proteins. In transformed cells, where it is frequently overexpressed, its intracellular localization and functions can be altered. Previously, we reported that treatment of highly metastatic, murine carcinoma H-59 cells with small molecule cysteine proteinase inhibitors altered the responsiveness of the type I insulin-like growth factor (IGF-I) receptor and consequently reduced cell invasion and metastasis. To assess more specifically the role of cathepsin L in IGF-I-induced signaling and tumorigenicity, we generated H-59 subclones with reduced cathepsin L expression levels. These clonal lines showed an altered responsiveness to IGF-I in vitro, as evidenced by (i) loss of IGF-I-induced receptor phosphorylation and Shc recruitment, (ii) reduced IGF-I (but not IGF-II)-induced cellular proliferation and migration, (iii) decreased anchorage-independent growth and (iv) reduced plasma membrane levels of IGF-IR. These changes resulted in increased apoptosis in vivo and an impaired ability of the cells to form liver metastases. The results demonstrate that cathepsin L expression levels regulate cell responsiveness to IGF-I and thereby identify a novel function for cathepsin L in the control of the tumorigenic/metastatic phenotype.

Inhibition of fibroblast growth factor/fibroblast growth factor receptor activity in glioma cells impedes tumor growth by both angiogenesis-dependent and -independent mechanisms.

We undertook a series of systematic studies to address the role of fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) activity in tumor growth and angiogenesis. We expressed dominant-negative FGFR2 (FGFR2-DN) or FGFR1 (FGFR1-DN) in glioma C6 cells by using constitutive or tetracycline-regulated expression systems. Anchorage-dependent or independent growth was inhibited in FGFR-DN-expressing cells. Tumor development after xenografting FGFR-DN-expressing cells in immunodeficient mice or after transplantation in rat brain was strongly inhibited. Quantification of microvessels demonstrated a significant decrease in vessel density in tumors derived from FGFR-DN-expressing cells. Furthermore, in a rabbit corneal assay, the angiogenic response after implantation of FGFR-DN-expressing cells was decreased. In tumors expressing FGFR-DN, vascular endothelial growth factor expression was strongly inhibited as compared with control tumor. These results indicate that inhibition of FGF activity may constitute a dominant therapeutic strategy in the treatment of FGF-producing cerebral malignancies and may disrupt both angiogenesis-dependent and -independent signals required for glioma growth and invasion.

Identification of a gp130 cytokine receptor critical site involved in oncostatin M response.

Gp130 cytokine receptor is involved in the formation of multimeric functional receptors for interleukin-6 (IL-6), IL-11, leukemia inhibitory factor (LIF), oncostatin M (OSM), ciliary neurotrophic factor, and cardiotrophin-1. Cloning of the epitope recognized by an OSM-neutralizing anti-gp130 monoclonal antibody identified a portion of gp130 receptor localized in the EF loop of the cytokine binding domain. Site-directed mutagenesis of the corresponding region was carried out by alanine substitution of residues 186-198. To generate type 1 or type 2 OSM receptors, gp130 mutants were expressed together with either LIF receptor beta or OSM receptor beta. When positions Val-189/Tyr-190 and Phe-191/Val-192 were alanine-substituted, Scatchard analyses indicated a complete abrogation of OSM binding to both type receptors. Interestingly, binding of LIF to type 1 receptor was not affected, corroborating the notion that in this case gp130 mostly behaves as a converter protein rather than a binding receptor. The present study demonstrates that positions 189-192 of gp130 cytokine binding domain are essential for OSM binding to both gp130/LIF receptor beta and gp130/OSM receptor beta heterocomplexes.

Ciliary neurotrophic factor is a regulator of muscular strength in aging.

Ciliary neurotrophic factor (CNTF) participates in the survival of motor neurons and reduces the denervation-induced atrophy of skeletal muscles. Experiments performed in rats show a decrease in peripheral CNTF synthesis during aging, associated with an overexpression of its alpha-binding receptor component by skeletal muscles. Measurement of sciatic nerve CNTF production and of the muscular performance developed by the animals revealed a strong correlation between the two studied parameters (r = 0.8; p < 0.0003). Furthermore, the twitch and tetanic tensions measured in the isolated soleus skeletal muscle in 24-month-old animals increased 2. 5-fold by continuous in vivo administration of CNTF. Analyses of the activation level of leukemia inhibitory factor receptor beta- and signal transducer and activator of transcription 3-signaling molecules in response to exogenous CNTF revealed an increased tyrosine phosphorylation positively correlated with the twitch tension developed by the soleus muscle of the animals.

Signaling of type II oncostatin M receptor.

Oncostatin M (OSM) mediates its bioactivities through two different heterodimer receptors. They both involve the gp130-transducing receptor, which dimerizes with either leukemia inhibitory receptor beta or with OSM receptor beta (OSMRbeta) to generate, respectively, type I and type II OSM receptors. Co-precipitation of gp130-associated proteins, flow cytometry, polymerase chain reaction, and tyrosine phosphorylation analyses allowed the characterization of both types of OSM receptors expressed on the surface of different cell lines. It also allowed the detection of a large size protein, p250, that specifically associates to the type II OSM receptor components and that is tyrosine-phosphorylated after the activation peak of the gp130.OSMRbeta heterocomplex. The restricted expression of type I OSM receptor by the JAR choriocarcinoma cell line, and type II receptor by the A375 melanoma cell line, permitted the characterization of their signaling machineries. Both type I and type II OSM receptors activated Jak1, Jak2, and Tyk2 receptor-associated tyrosine kinases. The information is next relayed to the nucleus by the STAT3 transcriptional activator, which is recruited by both types of OSM receptors. In addition, STAT5b was specifically activated through the gp130.OSMRbeta type II heterocomplex. The signaling pathway differences observed between the common type I LIF/OSM receptor and the specific type II OSM receptor might explain some of the bioactivities specifically displayed by OSM.

Signaling of the cardiotrophin-1 receptor. Evidence for a third receptor component.

Cardiotrophin-1 (CT-1) is a recently isolated cytokine belonging to the interleukin-6 cytokine family. In the present study we show that CT-1 activates its receptor expressed at the surface of a human neural cell line by recruiting gp130 and gp190/leukemia inhibitory factor receptor beta, as shown by analyzing their tyrosine phosphorylation level. Neutralizing antibody directed against gp130 and reconstitution experiments performed in the COS-7 cell line demonstrate that gp130-gp190 heterocomplex formation is essential for CT-1 signaling. Analysis of the subsequent activation events revealed that CT-1 induces and utilizes Jak1-, Jak2-, and Tyk2-associated tyrosine kinases, which are in turn relayed by STAT-3 transcription factor. Cross-linking of iodinated CT-1 to the cell surface led to the identification of a third alpha component in addition to gp130 and gp190, with an apparent molecular mass of 80 kDa. Removal of N-linked carbohydrates from the protein backbone of the alpha component resulted in a protein of 45 kDa. Our results provide evidence that the CT-1 receptor is composed of a tripartite complex, a situation similar to the high affinity receptor for ciliary neurotrophic factor.

Alanine substitution for Thr268 and Asp269 of soluble ciliary neurotrophic factor (CNTF) receptor alpha component defines a specific antagonist for the CNTF response.

Ciliary neurotrophic factor (CNTF) associates with an alpha subunit (CNTFRalpha) of the receptor complex to initiate signal transduction by facilitating heterodimerization of the gp130 transducing protein and the leukemia inhibitory factor receptor (LIFR) beta. CNTFRalpha is anchored to the membrane by a glycosylphosphatidylinositol linkage; however, a soluble form of the alpha subunit can still bind CNTF to recruit the signal transducing components of the receptor complex. In the present study we show that alanine substitution for residues Thr268 and Asp269 of the CNTFRalpha subunit results in a mutated receptor subunit (R3), which can bind CNTF with an affinity similar to that of the wild type CNTFRalpha but, when expressed as a soluble receptor subunit, lowers the binding of CNTF to its tripartite receptor. In addition, CNTFR3alpha inhibits the proliferation of the TF1 hematopoietic cell line triggered by CNTF plus soluble wild type CNTFRalpha but not by IL-6 or oncostatin M. Similarly, CNTFR3alpha specifically antagonizes the induction of gp130 and LIFRbeta tyrosine phosphorylation observed in response to CNTF and wild type soluble CNTFRalpha in the HepG2 hepatoma cell line, as well as the subsequent events leading to haptoglobin synthesis. Positions 268 and 269 of CNTFRalpha appear to be critical for its interaction with gp130 and LIFRbeta, whereby alanine substitution of the residues at these positions results in antagonism of the CNTF-induced response.

Binding interactions of leukemia inhibitory factor and ciliary neurotrophic factor with the different subunits of their high affinity receptors.

Leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF) share common components in their multimeric receptors. Both cytokine receptors contain gp130/interleukin-6-receptor transducer as well as gp190/low affinity LIF receptor. For CNTF, addition of a third subunit, or alpha subunit, defines the high-affinity CNTF receptor. In the present study, we analyzed the binding interactions of LIF and CNTF in human cell lines and showed a mutual displacement for LIF and CNTF toward the trimeric high-affinity CNTF receptor. Similar results were obtained in the JEG cell line, which only expressed the gp130/gp190 high-affinity LIF receptor, by adding a soluble form of the alpha CNTF receptor to the system to reconstitute the high-affinity-type CNTF receptor. The different receptor subunits were then expressed separately in transfected cells and their binding capacities analyzed. The results showed that the heterocomplex CNTF/alpha CNTF receptor bound to gp130 with an affinity of 3-5 x 10(-10)M, whereas LIF interacted mainly with gp190. In summary, the observed competition between LIF and CNTF does not result from the binding to a common site or receptor subunit, but rather to the interaction of the three receptor components to create a conformational site common to both LIF and CNTF.