Population screening for lung cancer using computed tomography, is there evidence of clinical effectiveness? A systematic review of the literature

Low-dose computed tomography for lung cancer screening in high-risk populations: a systematic review and economic evaluation

BACKGROUND

Diagnosis of lung cancer frequently occurs in its later stages. Low-dose computed tomography (LDCT) could detect lung cancer early.

OBJECTIVES

To estimate the clinical effectiveness and cost-effectiveness of LDCT lung cancer screening in high-risk populations.

DATA SOURCES

Bibliographic sources included MEDLINE, EMBASE, Web of Science and The Cochrane Library.

METHODS

Clinical effectiveness - a systematic review of randomised controlled trials (RCTs) comparing LDCT screening programmes with usual care (no screening) or other imaging screening programmes [such as chest X-ray (CXR)] was conducted. Bibliographic sources included MEDLINE, EMBASE, Web of Science and The Cochrane Library. Meta-analyses, including network meta-analyses, were performed. Cost-effectiveness - an independent economic model employing discrete event simulation and using a natural history model calibrated to results from a large RCT was developed. There were 12 different population eligibility criteria and four intervention frequencies [(1) single screen, (2) triple screen, (3) annual screening and (4) biennial screening] and a no-screening control arm.

RESULTS

Clinical effectiveness - 12 RCTs were included, four of which currently contribute evidence on mortality. Meta-analysis of these demonstrated that LDCT, with ≤ 9.80 years of follow-up, was associated with a non-statistically significant decrease in lung cancer mortality (pooled relative risk 0.94, 95% confidence interval 0.74 to 1.19). The findings also showed that LDCT screening demonstrated a non-statistically significant increase in all-cause mortality. Given the considerable heterogeneity detected between studies for both outcomes, the results should be treated with caution. Network meta-analysis, including six RCTs, was performed to assess the relative clinical effectiveness of LDCT, CXR and usual care. The results showed that LDCT was ranked as the best screening strategy in terms of lung cancer mortality reduction. CXR had a 99.7% probability of being the worst intervention and usual care was ranked second. Cost-effectiveness - screening programmes are predicted to be more effective than no screening, reduce lung cancer mortality and result in more lung cancer diagnoses. Screening programmes also increase costs. Screening for lung cancer is unlikely to be cost-effective at a threshold of £20,000/quality-adjusted life-year (QALY), but may be cost-effective at a threshold of £30,000/QALY. The incremental cost-effectiveness ratio for a single screen in smokers aged 60-75 years with at least a 3% risk of lung cancer is £28,169 per QALY. Sensitivity and scenario analyses were conducted. Screening was only cost-effective at a threshold of £20,000/QALY in only a minority of analyses.

LIMITATIONS

Clinical effectiveness - the largest of the included RCTs compared LDCT with CXR screening rather than no screening. Cost-effectiveness - a representative cost to the NHS of lung cancer has not been recently estimated according to key variables such as stage at diagnosis. Certain costs associated with running a screening programme have not been included.

CONCLUSIONS

LDCT screening may be clinically effective in reducing lung cancer mortality, but there is considerable uncertainty. There is evidence that a single round of screening could be considered cost-effective at conventional thresholds, but there is significant uncertainty about the effect on costs and the magnitude of benefits.

FUTURE WORK

Clinical effectiveness and cost-effectiveness estimates should be updated with the anticipated results from several ongoing RCTs [particularly the NEderlands Leuvens Longkanker Screenings ONderzoek (NELSON) screening trial].

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016048530.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Do we know enough about the effect of low-dose computed tomography screening for lung cancer on survival to act? A systematic review, meta-analysis and network meta-analysis of randomised controlled trials

BACKGROUND

Diagnosis of lung cancer frequently occurs in its later stages. Low-dose computed tomography (LDCT) could detect lung cancer early.

METHODS

Our objective was to estimate the effect of LDCT lung cancer screening on mortality in high-risk populations. A systematic review of randomised controlled trials (RCTs) comparing LDCT screening programmes with usual care (no screening) or other imaging screening programme (such as chest X-ray (CXR)) was conducted. RCTs of CXR screening were additionally included in the network meta-analysis. Bibliographic sources including MEDLINE, Embase, Web of Science and the Cochrane Library were searched to January 2017. All key review steps were done by two persons. Quality assessment used the Cochrane Risk of Bias tool. Meta-analyses were performed.

RESULTS

Four RCTs were included. More will provide data in the future. Meta-analysis demonstrated that LDCT screening with up to 9.80 years of follow-up was associated with a statistically non-significant decrease in lung cancer mortality (pooled relative risk (RR) 0.94, 95% confidence interval (CI) 0.74 to 1.19; p = 0.62). There was a statistically non-significant increase in all-cause mortality. Given the considerable heterogeneity for both outcomes, the results should be treated with caution.Network meta-analysis including the four original RCTs plus two further RCTs assessed the relative effectiveness of LDCT, CXR and usual care. The results showed that in terms of lung cancer mortality reduction LDCT was ranked as the best screening strategy, CXR screening as the worst strategy and usual care intermediate.

CONCLUSIONS

LDCT screening may be effective in reducing lung cancer mortality but there is considerable uncertainty: the largest of the RCTs compared LDCT with CXR screening rather than no screening; there is imprecision of the estimates; and there is important heterogeneity between the included study results. The uncertainty about the effect on all-cause mortality is even greater. Maturing trials may resolve the uncertainty.

Low-dose computed tomography (LDCT) versus other cancer screenings in early diagnosis of lung cancer: A meta-analysis

BACKGROUND

Lung cancer is the leading cause of cancer mortality worldwide. It is often diagnosed at an advanced stage when treatment is no longer possible. Early population-based screening may provide an opportunity for early diagnosis and reduce mortality rates.

METHODS

Study characteristics were collected and outcome data (lung cancer diagnosis and mortality) were extracted and used for meta-analysis. Statistical analyses were performed using OpenMetaAnalyst-0.1503 software. The odds ratio (OR) and 95% confidence interval (CI) were used to assess LDCT compared to other screening methods under the random-effects model. The I2 statistic was used to assess heterogeneity.

RESULTS

Pooling data from 4 studies (64,129 patients) showed a higher incidence of diagnosed lung cancer with LDCT screening (OR = 1.86, 95% CI: 1.02-3.37), compared to other screening tools. However, no significant difference (OR = 1.13, 95% CI: 0.78-1.64) was found in lung cancer mortality between both groups.

CONCLUSIONS

Although no significant difference was found between LDCT and other control groups in terms of lung cancer mortality, this meta-analysis suggests an increased diagnosis of lung cancer with LDCT as compared with other screening modalities. This meta-analysis displays the potential but also the limitations of LDCT for early lung cancer detection.

Screening for Lung Cancer

Lung cancer is a global health burden and is among the most common and deadliest of all malignancies worldwide. The goal of screening programs is to detect tumors in earlier, curable stages, consequently reducing disease-specific mortality. The issue of screening has great relevance to thoracic surgeons, who should play a leading role in the debate over screening and its consequences. The burden is on thoracic surgeons to work in a multidisciplinary setting to guide and treat these patients safely and responsibly, ensuring low morbidity and mortality of potential diagnostic or therapeutic interventions.

The UK Lung Cancer Screening Trial: a pilot randomised controlled trial of low-dose computed tomography screening for the early detection of lung cancer

BACKGROUND

Lung cancer kills more people than any other cancer in the UK (5-year survival < 13%). Early diagnosis can save lives. The USA-based National Lung Cancer Screening Trial reported a 20% relative reduction in lung cancer mortality and 6.7% all-cause mortality in low-dose computed tomography (LDCT)-screened subjects.

OBJECTIVES

To (1) analyse LDCT lung cancer screening in a high-risk UK population, determine optimum recruitment, screening, reading and care pathway strategies; and (2) assess the psychological consequences and the health-economic implications of screening.

DESIGN

A pilot randomised controlled trial comparing intervention with usual care. A population-based risk questionnaire identified individuals who were at high risk of developing lung cancer (≥ 5% over 5 years).

SETTING

Thoracic centres with expertise in lung cancer imaging, respiratory medicine, pathology and surgery: Liverpool Heart & Chest Hospital, Merseyside, and Papworth Hospital, Cambridgeshire.

PARTICIPANTS

Individuals aged 50-75 years, at high risk of lung cancer, in the primary care trusts adjacent to the centres.

INTERVENTIONS

A thoracic LDCT scan. Follow-up computed tomography (CT) scans as per protocol. Referral to multidisciplinary team clinics was determined by nodule size criteria.

MAIN OUTCOME MEASURES

Population-based recruitment based on risk stratification; management of the trial through web-based database; optimal characteristics of CT scan readers (radiologists vs. radiographers); characterisation of CT-detected nodules utilising volumetric analysis; prevalence of lung cancer at baseline; sociodemographic factors affecting participation; psychosocial measures (cancer distress, anxiety, depression, decision satisfaction); and cost-effectiveness modelling.

RESULTS

A total of 247,354 individuals were approached to take part in the trial; 30.7% responded positively to the screening invitation. Recruitment of participants resulted in 2028 in the CT arm and 2027 in the control arm. A total of 1994 participants underwent CT scanning: 42 participants (2.1%) were diagnosed with lung cancer; 36 out of 42 (85.7%) of the screen-detected cancers were identified as stage 1 or 2, and 35 (83.3%) underwent surgical resection as their primary treatment. Lung cancer was more common in the lowest socioeconomic group. Short-term adverse psychosocial consequences were observed in participants who were randomised to the intervention arm and in those who had a major lung abnormality detected, but these differences were modest and temporary. Rollout of screening as a service or design of a full trial would need to address issues of outreach. The health-economic analysis suggests that the intervention could be cost-effective but this needs to be confirmed using data on actual lung cancer mortality.

CONCLUSIONS

The UK Lung Cancer Screening (UKLS) pilot was successfully undertaken with 4055 randomised individuals. The data from the UKLS provide evidence that adds to existing data to suggest that lung cancer screening in the UK could potentially be implemented in the 60-75 years age group, selected via the Liverpool Lung Project risk model version 2 and using CT volumetry-based management protocols.

FUTURE WORK

The UKLS data will be pooled with the NELSON (Nederlands Leuvens Longkanker Screenings Onderzoek: Dutch-Belgian Randomised Lung Cancer Screening Trial) and other European Union trials in 2017 which will provide European mortality and cost-effectiveness data. For now, there is a clear need for mortality results from other trials and further research to identify optimal methods of implementation and delivery. Strategies for increasing uptake and providing support for underserved groups will be key to implementation.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN78513845.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 40. See the NIHR Journals Library website for further project information.

A systematic review of the characteristics associated with recall rates, detection rates and positive predictive values of computed tomography screening for lung cancer

BACKGROUND

Low-dose computed tomography (LDCT) screening has been shown to reduce mortality from lung cancer but at a substantial cost in diagnostic activity. The objective of this study was to investigate the characteristics of screening programmes associated with recall rates, detection rates and positive predictive values (PPVs).

DESIGN

We conducted a systematic review of randomised trials and observational studies on LDCT screening for lung cancer. A meta-regression using random-effect logistic regressions was carried out to assess factors influencing recall rates for further investigation, cancer detection rates and PPVs of recall.

RESULTS

We used data from 63 372 prevalent screens from 16 studies of LDCT screening for lung cancer and 79 302 incident screens from nine studies. In univariable analysis, the use of a cut-off size to define nodules warranting further investigation at prevalent screens reduced recall rates [odds ratio (OR) = 0.44, 95% confidence interval (CI) 0.24-0.82 and OR = 0.42, 95% CI 0.21-0.84 for cut-off sizes of 3-4 and 5-8 mm, respectively], without significant changes in detection rates and PPVs. The number of readers (1 or ≥2) was not associated with changes in recall rates, detection rates and PPVs at prevalent and incident screens. Using the volumetry software at incident screens significantly increased the PPV (OR = 5.02, 95% CI 1.65-15.28) as a result of a decrease in recall rates (OR = 0.25, 95% CI 0.12-0.51), without significant changes in detection rates.

CONCLUSION

These results highlight the value of using a cut-off size for nodules warranting further investigation with lower recall rates at prevalent screens, whereas the volumetric assessment software at incident screens results in lower recall rates and higher PPVs. The presence of positron emission tomography in the work-up protocol might be associated with lower rates of surgical procedures for benign findings, although this hypothesis deserves further investigation.

[(18)F]Fluorodeoxyglucose-positron emission tomography screening for lung cancer: a systematic review and meta-analysis

Rationale and objectives: Although low-dose computed tomography (CT) is a recommended modality for lung cancer screening in high-risk populations, the role of other modalities, such as [¹⁸F]fluorodeoxyglucose-positron emission tomography (PET), is unclear. We conducted a systematic review to describe the role of PET in lung cancer screening. Materials and methods: A systematic review was conducted by reviewing primary studies focusing on PET screening for lung cancer until July 2012. Two independent reviewers identified studies that were compatible for inclusion/exclusion criteria. The analysis was restricted to English and included studies published since 2000. A descriptive analysis was used to summarize the results, and the pooled diagnostic performance of selective PET screening was calculated by weighted average using individual sample sizes. Results: Among the identified studies (n = 3497), 12 studies were included for analysis. None of the studies evaluated the efficacy of primary PET screening specific to lung cancer. Eight studies focused on primary PET screening for all types of cancer; the detection rates of lung cancer were low. Four studies reported evidence of lung cancer screening programs with selective PET, in which the estimated pooled sensitivity and specificity was 83% and 91%, respectively. Conclusions: The role of primary PET screening for lung cancer remains unknown. However, PET has high sensitivity and specificity as a selective screening modality. Further studies must be conducted to evaluate the use of PET or PET/computed tomography screening for high-risk populations, preferably using randomized trials or prospective registration. Advances in knowledge: Our meta-analysis indicates that PET has high sensitivity and specificity as a selective screening modality.

Cancer screening: the journey from epidemiology to policy

PURPOSE

Cancer screening procedures have brought great benefit to the public's health. However, the science of cancer screening and the evidence arising from research in this field as it is applied to policy is complex and has been difficult to communicate, especially on the national stage. We explore how epidemiologists have contributed to this evidence base and to its translation into policy.

METHODS

Our essay focuses on breast and lung cancer screening to identify commonalities of experience by epidemiologists across two different cancer sites and describe how epidemiologists interact with evolving scientific and policy environments.

RESULTS

We describe the roles and challenges that epidemiologists encounter according to the maturity of the data, stakeholders, and the related political context. We also explore the unique position of cancer screening as influenced by the legislative landscape where, due to recent healthcare reform, cancer screening research plays directly into national policy.

CONCLUSIONS

In the complex landscape for cancer screening policy, epidemiologists can increase their impact by learning from past experiences, being well prepared and communicating effectively.

Potential of computer-aided diagnosis to improve CT lung cancer screening

The development of low-dose spiral computed tomography (CT) has rekindled hope that effective lung cancer screening might yet be found. Screening is justified when there is evidence that it will extend lives at reasonable cost and acceptable levels of risk. A screening test should detect all extant cancers while avoiding unnecessary workups. Thus optimal screening modalities have both high sensitivity and specificity. Due to the present state of technology, radiologists must opt to increase sensitivity and rely on follow-up diagnostic procedures to rule out the incurred false positives. There is evidence in published reports that computer-aided diagnosis technology may help radiologists alter the benefit-cost calculus of CT sensitivity and specificity in lung cancer screening protocols. This review will provide insight into the current discussion of the effectiveness of lung cancer screening and assesses the potential of state-of-the-art computer-aided design developments.

Screening for lung cancer: challenges for the thoracic surgeon

Lung cancer is a global health burden and is among the most common and deadly of all malignancies worldwide. Early detection of resectable and potentially curable disease may reduce the overall death rate from lung cancer. However, at the present time, screening for lung cancer is not recommended by most clinical societies and health care agencies in the United States. This article discusses the history of, and rationale for, lung cancer screening, addresses optimization of screening protocols, and describes our current approach for the evaluation of small pulmonary nodules referred for surgical management.

Causes of widening life expectancy inequalities in Québec, Canada, 1989-2004

OBJECTIVES

Inequalities in life expectancy between the most and least materially deprived areas in the province of Quebec, Canada are increasing, but the reasons for this trend are unclear. An analysis of which causes of death, in which age groups, are implicated in this trend is necessary to understand it and provide clear targets for intervention.

METHODS

We analyzed Quebec mortality data for three 4-year periods from 1989-2004. Differences in life expectancy at birth between the most- and least-deprived areas in each period and over time were decomposed by age and cause of death for men and women using the Arriaga method.

RESULTS

Life expectancy increased for all areas, but the increase was smaller in deprived areas. Cancer, heart disease and unintentional injuries accounted for the largest shares of inequality in each period. Among women, the widening life expectancy gap was largely due to increased lung cancer mortality. Among men, mortality from HIV was an important cause of widening inequality. Increasing inequality in both sexes was offset by a decrease in mortality from unintentional injuries in deprived areas (narrowing the gap between the most- and least-deprived areas). The largest share of inequality among women was due to deaths in the 65-and-over age group. Among men, the largest share shifted over time from middle-age to the 65-and-over age group.

CONCLUSION

The widening life expectancy gap between advantaged and disadvantaged areas in Quebec is driven by relatively few causes of death with well-known risk factors and strategies for prevention.

TGF-β1 serum concentration as a complementary diagnostic biomarker of lung cancer: establishment of a cut-point value

Lung cancer is a malignant disease with increasing mortality rates. Cytokines play a role in normal cell growth regulation and differentiation and are also implicated in malignant disease. Among these cytokines, Transforming Growth Factor β type 1 (TGF-β1) acts as a tumor promoter in malignant cells. Several clinical studies have found high levels of TGF-β1 in various cancer types. The aim of this study was to establish a TGF-β1 cut-off point as a complementary diagnostic tool in lung cancer detection. Therefore, 72 clinically well-characterized individuals were studied, 41 lung cancer patients and 31 healthy subjects. Serum TGF-β1 concentration was measured by an enzyme-linked immunosorbent assay (ELISA). We compared statistically the serum TGF-β1 concentration between both groups with analysis of variance, linear regression and receiver operating curve analysis. We observed that lung cancer patients produced higher TGF-β1 levels than healthy individuals (37,225±9,436 vs. 28,416±9,324 pg/ml, P<0.001). The cut-point diagnostic value was 30,500 pg/ml with 80.5% sensitivity, 64.5% specificity and odds ratio: 7.5, 95% CI: 2.6-21.8.

CONCLUSIONS

We found significantly higher TGF-β1 levels in lung cancer patients than in healthy individuals. We propose the measurement of serum TGF-β1 levels as a complementary diagnostic test in lung cancer detection.

CT scans for pulmonary surveillance may be overused in lower-grade sarcoma

Chest CT scans are often used to monitor patients after excision of a sarcoma. Although sensitive, CT scans are more expensive than chest radiographs and are associated with possible health risks from a higher radiation dose. We hypothesized that a program based upon limited CT scans in lower-grade sarcoma could be efficacious and less expensive. We retrospectively assigned patients to a high-risk or low-risk hypothetical protocol. Eighty-three low- or intermediate-grade soft tissue sarcomas met our inclusion criteria. Eight patients had pulmonary metastasis. A protocol based on selective CT scans for high-risk patients would have identified seven out of eight lesions. The incremental cost-effectiveness ratio for routine CT scans was $731,400. A program based upon selective CT scans for higher-risk patients is accurate, spares unnecessary radiation to many patients, and is less expensive.

Detection rate of lung cancer among chronic obstructive pulmonary disease patients regularly followed up by pulmonary physicians

BACKGROUND

  Chronic obstructive pulmonary disease (COPD) has been found to be an independent risk factor for lung cancer. The aim of this study was to evaluate whether regular follow up of COPD patients increases the diagnosis of lung cancer at an early stage.

METHODS

  Case reports of 105 male moderate to severe COPD patients who participated in a clinical study were analyzed retrospectively. Throughout the 3-year study period patients regularly visited a pulmonary physician. Investigations to detect lung cancer were ordered only with the presence of symptoms. The lung cancer incidence in the study group was compared to that of general male population matched by age.

RESULTS

  At the beginning of the study the mean age was 67 (range 55-81) years, mean smoking history 36.2 (range 11-102) years and mean forced expiratory volume in 1 s (FEV₁ ) 43.3% (range 22.7-59.7). During the study six lung cancers and five other cancers were diagnosed per 287 person-years of observation. Only one lung cancer was operable, others were locally advanced or had distant metastases.

CONCLUSIONS

  Despite the patients being followed up regularly by a pulmonary physician, most cancers were diagnosed at an advanced stage. The relative risk of getting lung cancer was 6.0 times higher (95% CI 2.7-13.3) among COPD patients than among the general population. The current study confirms that COPD patients have an increased risk of lung cancer. Moreover simple regular follow up of patients without special lung cancer screening investigations do not help to detect the cancer in its early stage. This study stresses the need to establish a more detailed follow-up program for COPD patients to detect early lung cancer in this high risk population.

Screening and early detection of lung cancer

Lung cancer with an estimated 342,000 deaths in 2008 (20% of total) is the most common cause of death from cancer, followed by colorectal cancer (12%), breast cancer (8%), and stomach cancer (7%) in Europe. In former smokers, the absolute lung cancer risk remains higher than in never-smokers; these data therefore call for effective secondary preventive measures for lung cancer in addition to smoking cessation programs. This review presents and discusses the most recent advances in the early detection and screening of lung cancer.An overview of randomized controlled computerized tomography-screening trials is given, and the role of bronchoscopy and new techniques is discussed. Finally, the approach of (noninvasive) biomarker testing in the blood, exhaled breath, sputum, and bronchoscopic specimen is reviewed.

Screening for lung cancer with low-dose computed tomography: a systematic review and meta-analysis of the baseline findings of randomized controlled trials

OBJECTIVES

Lung cancer is the leading cause of death among all cancers. An estimated 29% of the global population older than 15 years currently smokes tobacco. The presence of a high risk population, relatively asymptomatic nature of the disease in the early phase, and relatively good prognosis when discovered early makes screening for lung cancer an attractive proposition. We performed a systematic review and a meta-analysis of the baseline results of randomized controlled trials so far published, which included more than 14,000 patients. Analysis was used to determine whether data was for or against the screening of lung cancers using low-dose computed tomography (LDCT).

DESIGN

Random effect meta regression model of meta-analysis and systematic review.

METHODS

We performed a systematic review and a meta-analysis of the current literature to determine whether screening for lung cancer in a high-risk population with computed tomography improves outcomes. A search strategy using Medline was employed, studies selected based on preset criteria and application of exclusion criteria, and data collected and analyzed for statistical significance.

RESULTS

Screening for lung cancer using LDCT resulted in a significantly higher number of stage I lung cancers (odds ratio 3.9, 95% confidence interval [CI] 2.0-7.4), higher number of total non-small cell lung cancers (odds ratio 5.5, 95% CI 3.1-9.6), and higher total lung cancers (odds ratio 4.1, 95% CI 2.4-7.1). Screening using LDCT also resulted in increased detection of false-positive nodules (odds ratio 3.1, 95% CI 2.6-3.7) and more unnecessary thoracotomies for benign lesions (event rate 3.7 per 1000, 95% CI 3.5-3.8). For every 1000 individuals screened with LDCT for lung cancer, 9 stage I non-small cell lung cancer and 235 false-positive nodules were detected, and 4 thoracotomies for benign lesions were performed.

CONCLUSIONS

The baseline data from six randomized controlled trials offer no compelling data in favor or against the use of LDCT screening for lung cancer. We await the final results of these randomized controlled trials to improve our understanding of the effectiveness of LDCT in the screening for lung cancer and its effect on mortality.

Lung cancer screening--are we there yet?

BACKGROUND

Lung cancer is the most lethal cancer and most cases are the result of cigarette smoking. Although a high risk target population for screening can be defined, and although early stage lung cancer has a much better prognosis than advanced disease, there is still no clear evidence that lung cancer screening decreases mortality. Accordingly, current guidelines suggest that there is no evidence to support routine screening. Although randomized studies in the 1970('s) which used chest x-ray and sputum for screening were clearly negative in the last 20 years more sensitive screening tools such as chest computed tomography have revolutionized the field. However, randomized controlled trials of computed tomography have only recently been launched. AIMS OF THIS REVIEW: Our objectives are to provide the reader with the rationale for screening for lung cancer, to review the older screening studies and their limitations, and to summarize the current knowledge and ongoing trials of lung cancer screening.

LITERATURE SEARCH

A literature search using Medline was conducted from 1966 onwards searching for articles with relevant key words such as lung cancer screening chest X - ray low dose computerized tomography cancer screening guideline. When appropriate additional references were found from the bibliographies of identified papers of interest.

CONCLUSIONS

Recent uncontrolled multicenter studies of chest computed tomography scans show encouraging results. However, until data from, large properly designed and appropriately analyzed randomized controlled trials which may overcome research biases is available, the benefit of lung cancer screening, if any is still unknown.

Joint registration and segmentation of serial lung CT images for image-guided lung cancer diagnosis and therapy

In image-guided diagnosis and treatment of small peripheral lung lesions the alignment of the pre-procedural lung CT images and the intra-procedural images is an important step to accurately guide and monitor the interventional procedure. Registering the serial images often relies on correct segmentation of the images and, on the other hand, the segmentation results can be further improved by temporal alignment of the serial images. This paper presents a joint serial image registration and segmentation algorithm. In this algorithm, serial images are segmented based on the current deformations, and the deformations among the serial images are iteratively refined based on the updated segmentation results. No temporal smoothness about the deformation fields is enforced so that the algorithm can tolerate larger or discontinuous temporal changes that often appear during image-guided therapy. Physical procedure models could also be incorporated to our framework to better handle the temporal changes of the serial images during intervention. In experiments, we apply the proposed algorithm to align serial lung CT images. Results using both simulated and clinical images show that the new algorithm is more robust compared to the method that only uses deformable registration.

Lung cancer screening update

PURPOSE OF REVIEW

Lung cancer is a health problem of global proportions. Despite intensive research over many years, the prognosis is still very poor. For the surgery to be effective, tumours need to be recognized early. Computed tomography (CT) is significantly more sensitive than chest radiograph for identifying small, asymptomatic lung cancers. Although low-dose CT screening observational trials have demonstrated that survival for all tumour types and sizes detected were extremely high, there is no clear evidence that low-dose CT screening reduces deaths from lung cancer. Only the results of ongoing randomized controlled trials can reveal a real benefit of screening in terms of mortality reduction.

RECENT FINDINGS

We summarize the protocols and the preliminary results of the lung cancer screening randomized controlled trial and the problems linked to the detection of suspected early cancer.

SUMMARY

Today, we cannot already prove the ultimate mortality benefit of lung cancer screening with low-dose CT nor we can confirm that this approach is not harmful. We are waiting the final analysis of randomized controlled trials for lung cancer mortality. Even if is widely accepted that pooling data of randomized controlled trials could be of help to get powerful results in terms of mortality reduction in shorter follow-up time, this opportunity is still under evaluation.

CT lung cancer screening in the UK

Lung cancer is the most common cause of cancer-related death in the UK. Despite aggressive primary prevention measures and improved medical care, the 5-year survival rate is less than 10% for patients in the UK who present with symptoms. The possibility of CT screening for lung cancer provides some hope of reducing mortality. However, the case for screening remains unproven. This article explores the issues surrounding lung cancer screening in the context of historical studies, trials in progress and tentative plans for a UK CT lung cancer screening trial.

Road ahead to respiratory health: experts chart future research directions

Respiratory illnesses are a huge and rising burden to health-care systems and societies worldwide. Research is crucial to tackle the enormous problem of chest diseases. However the vast number of research questions and available research approaches often creates confusion and risks dilution of resources by spreading them too diffusely. Clear research directions will help to use research funds efficiently to provide treatment advances that benefit patient care. This paper presents the visions of leading experts on future research directions, focusing on what should rather than what is going to be done. These opinions provide a guide for new investigators and a platform for intellectual debates through which coordinated research efforts can help progress towards respiratory health.

Pulmonary nodules detected at cardiac CT: comparison of images in limited and full fields of view

OBJECTIVE

The purpose of this study was to compare the frequency of detection of pulmonary nodules on cardiac CT scans acquired with a limited field of view with the frequency of detection at full field of view.

CONCLUSION

Viewing of cardiac CT scans obtained only at a limited field of view can result in missing more than 67% of nodules larger than 1 cm and more than 80% of nodules smaller than 1 cm.

Lung cancer screening: the way forward

To take lung cancer screening into national programmes, we first have to answer the question whether low-dose computed tomography (LDCT) screening and treatment of early lesions will decrease lung cancer mortality compared with a control group, to accurately estimate the balance of benefits and harms, and to determine the cost-effectiveness of the intervention.

Lung cancer screening: has there been any progress? Computed tomography and autofluorescence bronchoscopy

PURPOSE OF REVIEW

Advances in imaging technologies are currently being explored in the attempt to reduce lung cancer morbidity and mortality by achieving stage shift. We reviewed recent important publications on lung cancer screening.

RECENT FINDINGS

Autofluorescence bronchoscopy has established its important role in the intervention of early central airway lesions. Multidetector computed tomography (CT) and CT-positron emission tomography may facilitate diagnosis of early parenchymal lung lesions. Practical implications of screening are reaching far beyond early diagnostic efforts per se as lead-time, length-time, overdiagnosis biases combined with low specificity of screening tests undermine its cost-effectiveness in the era of healthcare budget constraints.

SUMMARY

Advanced imaging technologies may allow early detection and prudent intervention in some individuals that harbour asymptomatic early lung cancer, but disproportional expenses may be required to sieve out many more individuals at risk to attain stage shift. Confounding co-morbidities and practical hurdles may reduce screening's efficacy as it is plausible that for the majority of smokers, lung cancer may not be the ultimate cause of suffering since 90% of them will not develop lung cancer. This fact remains true despite increased use of noninvasive and minimally invasive technologies for the maximum preservation of quality of life irrespective of whether early intervention is a success or failure.