A randomized study of lung cancer screening with spiral computed tomography: three-year results from the DANTE trial

Lung cancer screening: the European perspective

European studies have contributed significantly to the understanding of lung cancer screening. Smoking within screening, quality of life, nodule management, minimally invasive treatments, cancer prevention programs, and risk models have been extensively investigated by European groups. Mortality data from European screening studies have not been encouraging so far, but long-term results of the NELSON study are eagerly awaited. Investigations on molecular markers of lung cancer are ongoing in Europe; preliminary results suggest they may become an important screening tool in the future.

Prospective CT screening for lung cancer in a high-risk population: HIV-positive smokers

BACKGROUND

Epidemiological evidence suggests that HIV-infected individuals are at increased risk of lung cancer, but no data exist because large computed tomography (CT) screening trials routinely exclude HIV-infected participants.

METHODS

From 2006 to 2013, we conducted the world's first lung cancer screening trial of 224 HIV-infected current/former smokers to assess the CT detection rates of lung cancer. We also used 130 HIV-infected patients with known lung cancer to determine radiographic markers of lung cancer risk using multivariate analysis.

RESULTS

Median age was 48 years with 34 pack-years smoked. During 678 person-years, one lung cancer was found on incident screening. Besides this lung cancer case, 18 deaths (8%) occurred, but none were cancer related. There were no interim diagnoses of lung or extrapulmonary cancers. None of the pulmonary nodules detected in 48 participants at baseline were diagnosed as cancer by study end. The heterogeneity of emphysema across the entire lung as measured by CT densitometry was significantly higher in HIV-infected subjects with lung cancer compared with the heterogeneity of emphysema in those without HIV (p ≤ 0.01). On multivariate regression analysis, increased age, higher smoking pack-years, low CD4 nadir, and increased heterogeneity of emphysema on quantitative CT imaging were all significantly associated with lung cancer.

CONCLUSIONS

Despite a high rate of active smoking among HIV-infected participants, only one lung cancer was detected in 678 patient-years. This was probably because of the young age of participants suggesting that CT screening of high-risk populations should strongly consider advanced age as a critical inclusion criterion. Future screening trials in urban American must also incorporate robust measures to ensure HIV patient compliance, adherence, and smoking cessation.

Surgeons and lung cancer screening: rules of engagement

To understand the challenges of screening for lung cancer, surgeons should be familiar with fundamental epidemiologic concepts pertaining to screening and have an understanding of the evidence regarding the various modalities used for screening lung cancer. One large, recent study has confirmed that screening for lung cancer with low-dose computed tomography decreases mortality in high-risk individuals. As a result of these findings, comprehensive screening programs are being developed. High-quality programs should be safe, cost-effective, accessible to high-risk patients, and involve the participation of a multidisciplinary team. Surgeons should be engaged in the implementation of screening programs for lung cancer.

The lung cancer epidemic in Spanish women: an analysis of mortality rates over a 37-year period

BACKGROUND

Lung cancer continues to be the leading cause of cancer-related mortality in the European Union (EU) and deaths from lung cancer have been projected to escalate to epidemic proportions amongst females over the next years. We examined lung cancer mortality rates in men and women from Andalusia (Spain) over a 37-year period [1975-2012].

METHODS

Longitudinal epidemiological study analyzing lung cancer mortality trends in males and females. Data on lung cancer mortality in Andalusia for the period 1975-2012 were obtained from the official cause-of-death publications of the Institute of Statistics of Andalusia. For each sex, age-standardized (European standard population) mortality rates (ASR) from lung cancer were calculated for all ages and truncated at 30-64, 65-74, and >75 years using the direct method. Standardized rate trends by age and sex were estimated by joinpoint regression analysis.

RESULTS

In men, the ASR steadily increased through the period 1993-1995, reaching a peak of 145.72 deaths/100,000 people. Subsequently, lung cancer deaths decreased to a rate of 125.47 in the 2011-2012 period. A moderate increase was seen in women until the late 1990s and early 2000s. Thereafter, a very notable rise was observed in females for all age groups, the only exception being older subjects. The sex differences decreased from 8.6:1 in the 1975-1977 period to 6.8:1 in the 2011-2012 period.

CONCLUSIONS

Lung cancer mortality rates decreased significantly in Andalusian men from 1975 to 2012. More importantly, we demonstrate for the first time the beginning of the lung cancer epidemics in Andalusian women as previously predicted for this area.

Screening and early detection efforts in lung cancer

Lung cancer is the leading cause of cancer-related death in the United States. Since publication of results from the National Lung Screening Trial, several professional organizations, including the US Preventive Services Task Force, have published guidelines recommending low-dose computed tomography for screening in asymptomatic, high-risk individuals. The benefits of screening include detection of cancer at an early stage when a definitive cure is possible, but the risks include overdiagnosis, false-positive results, psychological distress, and radiation exposure. The current review covers the scope of low-dose computed tomography screening, potential risks, costs, and future directions in the efforts for early detection of lung cancer.

Implementing Lung Cancer Screening Using Low-Dose Computed Tomography: Recommendations From an Expert Panel

Implementation of effective and efficient population-based CT lung cancer screening will require involvement and coordination of stakeholders across the health care system.

Low-dose computed tomography screening for lung cancer: results of the first screening round

Evaluation of: National Lung Screening Trial Research Team, Church TR, Black WC, Aberle DR et al. Results of initial low-dose computed tomographic screening for lung cancer. N. Engl. J. Med. 368, 1980-1991 (2013). In 2011, the US NLST trial demonstrated that mortality from lung cancer can be reduced by using low-dose computed tomography (LDCT) screening rather than chest x-ray (CXR) screening. This paper from the US NLST research team focuses on the results of the initial round of LDCT for lung cancer. A total of 53,439 participants were included and randomly assigned to LDCT screening (n = 26,715) or CXR screening (n = 26,724). In total, 27.3% of the participants in the LDCT group and 9.2% in the CXR group had a positive screening result. As a result, 3.8% (LDCT group) and 5.7% (CXR group) of these subjects were diagnosed with lung cancer. The sensitivity (93.8%) and specificity (73.4%) for lung cancer were higher for LDCT compared with CXR screening; 73.5 and 91.3%, respectively.

Assessing the benefits and harms of low-dose computed tomography screening for lung cancer

The concept of using low-dose computed tomography (LDCT) for lung cancer screening goes back almost 25 years. In 2011, the National Lung Screening Trial (NLST) reported that LDCT screening significantly reduced mortality from lung cancer in a high risk population. This article evaluates the benefits and harms of LDCT screening, based largely on evidence from randomized trials. Harms include false-positive screens and resultant diagnostic procedures, overdiagnosed cancers, and radiation exposure. Benefits can be expressed as the number needed to be screened to prevent one lung cancer death or as estimated overall reductions in lung cancer mortality assuming LDCT population screening as recommended by guidelines. Indirect metrics of benefit, such as lung cancer survival and stage distribution, as well as measures of harms, will be important to monitor in the future as LDCT screening disseminates in the population.

A meta-analysis: is low-dose computed tomography a superior method for risky lung cancers screening population?

BACKGROUND AND AIMS

Low-dose computed tomography (LDCT) has been proposed to be a new screening method to discover lung cancers in an early stage, especially those patients who are in a high risk of lung cancer. The primary objective of this meta-analysis is to systematically review the effect of LDCT on screening for lung cancers among the risky population who are older than 49 years old and with smoking exposure.

METHODS

We searched randomized controlled clinical trials (RCTs) about comparing LDCT and chest X-ray or usual caring from MEDLINE, EMBASE, and the Cochrane Library, Web of Knowledge and SpringerLink databases (January 1994 to September 2013).

RESULTS

Nine RCTs met criteria for inclusion. Screening for lung cancer using LDCT resulted in a significantly higher number of stage I lung cancers [odds ratio (OR) 2.15, 95% confidence interval (CI) 1.88-2.47], higher number of total lung cancers (OR 1.31, 95% CI 1.20-1.43) than the control. Four of the nine studies indicated that the screening method did not decrease all-cause mortality (OR 0.96, 95% CI 0.90-1.02), but decreased lung cancer-specific mortality (OR 0.84, 95% CI 0.74-0.96). Five studies showed that LDCT had higher false-positive rates (OR 8.7, 95% CI 7.43-10.19) than the group of control.

CONCLUSION

Among the risky population, LDCT screening find out more stage I lung cancers and total lung cancers compared with chest X-ray or no screening, and also shows advantages in decreasing lung cancer-specific mortality, but the screening method does not decrease all-cause mortality and have a higher false-positive rates in diagnosis.

Lung cancer screening: advantages, controversies, and applications

BACKGROUND

Lung cancer is the leading cause of cancer death in the United States. Results from the National Lung Screening Trial (NLST) have shown that low-dose computed tomography (CT) is capable of detecting lung neoplasms in individuals at high risk. However, whether it is advantageous to perform lung cancer screening on these patients is a significant concern, as are the potential adverse outcomes from screening.

METHODS

A review of several randomized clinical trials, focusing on the NLST, was undertaken. Adverse outcomes and costs related to lung cancer screening were also examined.

RESULTS

Lung cancer screening using low-dose CT in high-risk individuals reduced lung cancer deaths by more than 20% when compared with those screened by chest radiography. False-positive results were seen in both groups, but the number of adverse events from the screening test and subsequent diagnostic procedures was low.

CONCLUSIONS

Lung cancer screening is controversial, but the NLST has demonstrated that such testing may reduce lung cancer deaths in high-risk individuals when performed with low-dose CT rather than chest radiography. Guidelines should be established to not only help identify an appropriate screening population, but also develop standards for radiological testing.

Screening for lung cancer

PURPOSE OF REVIEW

The purpose of this review is to provide an update on the current data about low-dose computed tomography (LD-CT) lung cancer screening.

RECENT FINDINGS

The National Lung Screening Trial (NLST) was the first study that provided statistical evidence that LD-CT screening for lung cancer significantly reduces lung cancer mortality by 20%. Three statistically underpowered European trials could not confirm the positive effect of LD-CT screening on lung cancer mortality. Major obstacles in lung cancer screening are overdiagnosis and the large number of false-positive results. In the NLST, more than 24% of the screens were positive, most of which (96.4%) proved to be benign in nature. Optimized protocols for the workup of detected nodules may help to reduce the number of false-positive screens.

SUMMARY

Currently, the NLST is the only sufficiently powered trial to report a lower mortality rate with LD-CT screening. Long-term follow-up data are still anticipated on the European screening trials. Furthermore, data on the extent of the potential dangers of LD-CT screening, such as overdiagnosis, false-positive results, and the effect of cumulative radiation dose, have yet to be investigated thoroughly.

Issues with implementing a high-quality lung cancer screening program

After a comprehensive review of the evidence, the United States Preventive Services Task Force recently endorsed screening with low-dose computed tomography as an early detection approach that has the potential to significantly reduce deaths due to lung cancer. Prudent implementation of lung cancer screening as a high-quality preventive health service is a complex challenge. The clinical evaluation and management of high-risk cohorts in the absence of symptoms mandates an approach that differs significantly from that of symptom-detected lung cancer. As with other cancer screenings, it is essential to provide to informed at-risk individuals a safe, high-quality, cost-effective, and accessible service. In this review, the components of a successful screening program are discussed as we begin to disseminate lung cancer screening as a national resource to improve outcomes with this lethal cancer. This information about lung cancer screening will assist clinicians with communications about the potential benefits and harms of this service for high-risk individuals considering participation in the screening process.

Lung cancer screening: subsequent evidences of national lung screening trial

The US National Lung Screening Trial (NLST) demonstrated a 20% reduction in lung cancer mortality and a 6.7% decrease in all-cause mortality. The NLST is the only trial showing positive results in a high-risk population, such as in patients with old age and heavy ever smokers. Lung cancer screening using a low-dose chest computed tomography might be beneficial for the high-risk group. However, there may also be potential adverse outcomes in terms of over diagnosis, bias and cost-effectiveness. Until now, lung cancer screening remains controversial. In this review, we wish to discuss the evolution of lung cancer screening and summarize existing evidences and recommendations.

CT lung cancer screening: where are we heading to?

SUMMARY 

Lung cancer screening has been the subject of controversies since the 1970s. After failure of chest x-ray and sputum cytology examination to decrease lung cancer mortality, there was a 15-year period of disillusion. Low-dose CT scan of the thorax provided a renewal of interest with prospective studies followed by randomized trials of which four have been published. Only one, the NLST trial involving 53,000 participants is positive with a 20% reduction in lung cancer specific mortality rate. The European studies are by far smaller, the largest being the Nelson study with 15,000 participants. There are some shortcomings and biases that must be known and well explained to the future participants to a lung cancer screening program. The cost/benefit ratio remains to be better analyzed.

Screening for lung cancer with low-dose computed tomography: a review of current status

Screening using low-dose computed tomography (CT) represents an exciting new development in the struggle to improve outcomes for people with lung cancer. Randomised controlled evidence demonstrating a 20% relative lung cancer mortality benefit has led to endorsement of screening by several expert bodies in the US and funding by healthcare providers. Despite this pivotal result, many questions remain regarding technical and logistical aspects of screening, cost-effectiveness and generalizability to other settings. This review discusses the rationale behind screening, the results of on-going trials, potential harms of screening and current knowledge gaps.

Comparative analyses of volatile organic compounds (VOCs) from patients, tumors and transformed cell lines for the validation of lung cancer-derived breath markers

Breath analysis for the purpose of non-invasive diagnosis of lung cancer has yielded numerous candidate compounds with still questionable clinical relevance. To arrive at suitable volatile organic compounds our approach combined the analysis of different sources: isolated tumor samples compared to healthy lung tissues, and exhaled breath from lung cancer patients and healthy controls. Candidate compounds were further compared to substances previously identified in the comparison of transformed and normal lung epithelial cell lines. For human studies, a breath sampling device was developed enabling automated and CO2-controlled collection of the end-tidal air. All samples were first preconcentrated on multibed sorption tubes and analyzed with gas chromatography mass spectrometry (GC-MS). Significantly (p < 0.05) higher concentrations in all three types of cancer samples studied were observed for ethanol and n-octane. Additional metabolites (inter alia 2-methylpentane, n-hexane) significantly released by lung cancer cells were observed at higher levels in cancer lung tissues and breath samples (compared to respective healthy controls) with statistical significance (p < 0.05) only in breath samples. The results obtained confirmed the cancer-related origin of volatile metabolites, e.g. ethanol and octane that were both detected at significantly (p < 0.05) elevated concentrations in all three kinds of cancer samples studied. This work is an important step towards identification of volatile breath markers of lung cancer through the demonstration of cancer-related origin of certain volatile metabolites.

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.

Predicted for greatness: 1994 molecule of the year--the DNA repair enzyme

Lung cancer mortality is the highest of any cancer. Primary prevention has stalled, however, new lung cancer screening trials of low-dose computerized tomography (LDCT) have shown that the mortality from lung cancer can be reduced by up to 20% among current and former smokers. There are potential harms that must be taken into account when evaluating any screening program. With LDCT, there is a 90% rate of false positives and the potential for high doses of radiation from subsequent workup of benign lesions. The development of biomarkers that might refine the ability of screening to identify individuals at high risk for developing and dying from lung cancer is a ripe area for investigation. Sevilya and colleagues have developed a highly promising set of biomarkers of DNA repair capacity that may satisfy that goal. The large estimate of risk, the thoughtful combination of functional assays of DNA repair capacity, and the population-based design of the study make it reasonable to test these biomarkers in a larger study.

Assessment of circulating microRNAs in plasma of lung cancer patients

Lung cancer is the most common cause of cancer deaths worldwide and numerous ongoing research efforts are directed to identify new strategies for its early detection. The development of non-invasive blood-based biomarkers for cancer detection in its preclinical phases is crucial to improve the outcome of this deadly disease. MicroRNAs (miRNAs) are a new promising class of circulating biomarkers for cancer detection and prognosis definition, but lack of consensus on data normalization methods for circulating miRNAs and the critical issue of haemolysis, has affected the identification of circulating miRNAs with diagnostic potential. We describe here an interesting approach for profiling circulating miRNAs in plasma samples based on the evaluation of reciprocal miRNA levels measured by quantitative Real-Time PCR. By monitoring changes of plasma miRNA-ratios, it is possible to assess the deregulation of tumor-related miRNAs and identify signatures with diagnostic and prognostic value. In addition, to avoid bias due to the release of miRNAs from blood cells, a miRNA-ratios signature distinguishing haemolyzed samples was identified. The method described was validated in plasma samples of lung cancer patients, but given its reproducibility and reliability, could be potentially applied for the identification of diagnostic circulating miRNAs in other diseases.

Would screening for lung cancer benefit 75- to 84-year-old residents of the United States?

Background: The National Lung Screening Trial demonstrated that screening for lung cancer improved overall survival (OS) and reduced lung cancer mortality in the 55- to 74-year-old age group by increasing the proportion of cancers detected at an early stage. Because of the increasing life expectancy of the American population, we investigated whether screening for lung cancer might benefit men and women aged 75–84 years.

Materials/Methods: Rates of non-small cell lung cancer (NSCLC) from 2000 to 2009 were calculated in both younger and older age groups using the surveillance epidemiology and end reporting database. OS and lung cancer-specific survival (LCSS) in patients with Stage I NSCLC diagnosed from 2004 to 2009 were analyzed to determine the effects of age and treatment.

Results: The per capita incidence of NSCLC decreased in the 55–74 cohort, but increased in the 75–84 cohort over the study period. Crude lung cancer death rates in the two age groups who had no specific treatment were 39.5 and 44.9%, respectively. These rates fell in both age groups when increasingly aggressive treatment was used. Rates of OS and LCSS improved significantly with increasingly aggressive treatment in the 75–84 age group. The survival benefits of increasingly aggressive treatment in 75- to 84-year-old females did not differ from their counterparts in the younger cohort.

Conclusion: Screening for lung cancer might be of benefit to individuals at increased risk of lung cancer in the 75–84 age group. The survival benefits of aggressive therapy are similar in females between 55–74 and 75–84 years old.

Serum miR-499 as a novel diagnostic and prognostic biomarker in non-small cell lung cancer

The aim of the present study was to determine whether serum miR-499 may be used as a biomarker for early detection of non-small cell lung cancer (NSCLC). The present study was designed as an initial screening phase and a subsequent validation phase. In the screening phase, we analyzed serum levels of miR-499 in a subset of 40 patients with stage I (n=20) and stage IV (n=20) NSCLC. In the validation phase, miR-499 expression levels in serum (n=514) and tissue (n=136) from NSCLC patients were detected in a large and independent cohort of 514 patients. miR-499 in the screening phase was found to be significantly elevated in the serum of stage I NSCLC patients compared with that in stage IV NSCLC patients (P<0.001). Validation analysis showed that serum miR-499 levels were robust in differentiating NSCLC patients from control subjects [area under the curve (AUC)=0.906; 95% confidence interval (CI)=0.879 to 0.929). Serum miR-499 levels were significantly lower in stage III and IV patients compared with those with stage I (both P<0.001) or II (both P<0.001). Low serum miR-499 levels were associated with shorter overall survival and served as an independent prognostic biomarker in NSCLC patients [hazard ratio (HR)=1.63; 95% CI=1.33-2.0; P<0.0001). In addition, low serum levels of miR-499 indicated a poor disease-free survival in stage I-II NSCLC patients. Serum miR-499 may prove to be a promising biomarker for early detection and prognosis prediction of NSCLC.

Translation of research results to simple estimates of the likely effect of a lung cancer screening programme in the United Kingdom

Background:

There is considerable interest in the possibility of provision of lung cancer screening services in many developed countries. There is, however, no consensus on the target population or optimal screening regimen.

Methods:

In this paper, we demonstrate the use of published results on lung cancer screening and natural history parameters to estimate the likely effects of annual and biennial screening programmes in different risk populations, in terms of deaths prevented and of human costs, including screening episodes, further investigation rates and overdiagnosis.

Results:

Annual screening with the UK Lung Screening Study eligibility criteria was estimated to result in 956 lung cancer deaths prevented and 457 overdiagnosed cancers from 330 000 screening episodes. Biennial screening would result in 802 lung cancer deaths prevented and 383 overdiagnosed cancers for 180 000 screening episodes.

Interpretation/conclusion:

The predictions suggest that the intervention effect could justify the human costs. The evidence base for low-dose CT screening for lung cancer pertains almost entirely to annual screening. The benefit of biennial screening is subject to additional uncertainty but the issue merits further empirical research.

CT screening for lung cancer: countdown to implementation

Implementation of lung cancer CT screening is currently the subject of a major policy decision within the USA. Findings of the US National Lung Screening Trial showed a 20% reduction in lung cancer mortality and a 6·7% decrease in all-cause mortality; subsequently, five US professional and clinical organisations and the US Preventive Services Task Force recommended that screening should be implemented. Should national health services in Europe follow suit? The European community awaits mortality and cost-effectiveness data from the NELSON trial in 2015-16 and pooled findings of European trials. In the intervening years, a recommendation is proposed that a demonstration trial is done in the UK. In this Review, we summarise the existing evidence and identify questions that remain to be answered before the implementation of international lung cancer screening programmes.

Clinical utility of a plasma-based miRNA signature classifier within computed tomography lung cancer screening: a correlative MILD trial study

PURPOSE

Recent screening trial results indicate that low-dose computed tomography (LDCT) reduces lung cancer mortality in high-risk patients. However, high false-positive rates, costs, and potential harms highlight the need for complementary biomarkers. The diagnostic performance of a noninvasive plasma microRNA signature classifier (MSC) was retrospectively evaluated in samples prospectively collected from smokers within the randomized Multicenter Italian Lung Detection (MILD) trial.

PATIENTS AND METHODS

Plasma samples from 939 participants, including 69 patients with lung cancer and 870 disease-free individuals (n = 652, LDCT arm; n = 287, observation arm) were analyzed by using a quantitative reverse transcriptase polymerase chain reaction-based assay for MSC. Diagnostic performance of MSC was evaluated in a blinded validation study that used prespecified risk groups.

RESULTS

The diagnostic performance of MSC for lung cancer detection was 87% for sensitivity and 81% for specificity across both arms, and 88% and 80%, respectively, in the LDCT arm. For all patients, MSC had a negative predictive value of 99% and 99.86% for detection and death as a result of disease, respectively. LDCT had sensitivity of 79% and specificity of 81% with a false-positive rate of 19.4%. Diagnostic performance of MSC was confirmed by time dependency analysis. Combination of both MSC and LDCT resulted in a five-fold reduction of LDCT false-positive rate to 3.7%. MSC risk groups were significantly associated with survival (χ1(2) = 49.53; P < .001).

CONCLUSION

This large validation study indicates that MSC has predictive, diagnostic, and prognostic value and could reduce the false-positive rate of LDCT, thus improving the efficacy of lung cancer screening.

Current status of lung cancer screening

Low-dose CT (LDCT) is effective in the early detection of lung cancer, providing higher resectability and long-term survival rates. The National Lung Screening Trial shows a statistically significant mortality reduction in LDCT compared with chest radiography. The efficacy and safety of annual LDCT screening in heavy smokers must be explored, and the magnitude of benefit compared with the cost of large-scale screening. Trials in Europe have different study designs and an observational arm. Strategies to reduce lung cancer mortality should combine early detection with primary prevention and innovative biologic approaches.

[Advance of lung cancer screening with low-dose spiral CT]

Lung cancer has become the leading cause of cancer mortality globally, and 5-year survival rate is very poor. Screening and early detection are vital to improve survival and decrease mortality of lung cancer. In recent 20 years, low-dose spiral CT (LDCT) screening has become a research focus in this area. Randomized controlled trials have confirmed that LDCT can decrease lung cancer mortality. However, there are still some problems of LDCT. In this paper, we summarized the controversy that whether low-dose helical CT screening can reduce lung cancer mortality or not before its effectiveness was been confirmed, the results and problems in the randomized controlled trials and gave a prospect of low-dose helical CT screening's future application.

Computed tomography screening for lung cancer: results of ten years of annual screening and validation of cosmos prediction model

INTRODUCTION

It is unclear how long low-dose computed tomographic (LDCT) screening should continue in populations at high risk of lung cancer. We assessed outcomes and the predictive ability of the COSMOS prediction model in volunteers screened for 10 years.

MATERIALS AND METHODS

Smokers and former smokers (>20 pack-years), >50 years, were enrolled over one year (2000-2001), receiving annual LDCT for 10 years. The frequency of screening-detected lung cancers was compared with COSMOS and Bach risk model estimates.

RESULTS

Among 1035 recruited volunteers (71% men, mean age 58 years) compliance was 65% at study end. Seventy-one (6.95%) lung cancers were diagnosed, 12 at baseline. Disease stage was: IA in 48 (66.6%); IB in 6; IIA in 5; IIB in 2; IIIA in 5; IIIB in 1; IV in 5; and limited small cell cancer in 3. Five- and ten-year survival were 64% and 57%, respectively, 84% and 65% for stage I. Ten (12.1%) received surgery for a benign lesion. The number of lung cancers detected during the first two screening rounds was close to that predicted by the COSMOS model, while the Bach model accurately predicted frequency from the third year on.

CONCLUSIONS

Neither cancer frequency nor proportion at stage I decreased over 10 years, indicating that screening should not be discontinued. Most cancers were early stage, and overall survival was high. Only a limited number of invasive procedures for benign disease were performed. The Bach model - designed to predict symptomatic cancers - accurately predicted cancer frequency from the third year, suggesting that overdiagnosis is a minor problem in lung cancer screening. The COSMOS model - designed to estimate screening-detected lung cancers - accurately predicted cancer frequency at baseline and second screening round.