Risk-Benefit Analysis of X-Ray Exposure Associated with Lung Cancer Screening in the Italung-CT Trial

Benefit-to-radiation-risk of low-dose computed tomography lung cancer screening

BACKGROUND

The US National Lung Screening Trial (NLST) and Dutch-Belgian NELSON randomized controlled trials have shown significant mortality reductions from low-dose computed tomography (CT) lung cancer screening (LCS). NLST, ITALUNG, and COSMOS trials have provided detailed dosimetry data for LCS.

METHODS

LCS trial mortality benefit results, organ dose and effective dose data, and Biological Effects of Ionizing Radiation, Report VII (BEIR VII) organ dose-to-cancer-mortality risk data are used to estimate benefit-to-radiation-risk ratios of the NLST, ITALUNG, and COSMOS trials. Data from those trials also are used to estimate benefit-to-radiation-risk ratios for longer-term LCS corresponding to scenarios recommended by United States Preventive Services Task Force and the American Cancer Society.

RESULTS

Including only screening doses, NLST benefit-to-radiation-risk ratios are 12:1 for males, 19:1 for females, and 16:1 overall. Including both screening and estimated follow-up doses, benefit-to-radiation-risk ratios for NLST are 9:1 for males, 13:1 for females, and 12:1 overall. For the ITALUNG trial, the benefit-to-radiation-risk ratio is 58-63:1. For the COSMOS trial, assuming sex-specific mortality benefits like those of the NELSON trial, the benefit-to-radiation-risk ratio is 23:1. Assuming a conservative 20% mortality benefit, annual screening in people 50-79 years old with a 20+ pack-year history of smoking has benefit-to-radiation-risk ratios of 23:1 (with follow-up doses adding 40% to screening doses) to 29:1 (with follow-up adding 10%) based on COSMOS dose data.

CONCLUSIONS

Based on linear, no threshold BEIR VII dose-risk estimates, benefit-to-radiation-risk ratios for LCS are highly favorable. Results emphasize the importance of using modern CT technologies, maintaining low diagnostic follow-up rates, and minimizing both screening and diagnostic follow-up doses.

PLAIN LANGUAGE SUMMARY

The benefits of lung cancer screening significantly outweigh estimates of future harms associated with exposure to radiation during screening and diagnostic follow-up examinations. Our findings emphasize the importance of lung cancer screening practices using state-of-the-art computed tomography scanners and specialized low-dose lung screening and diagnostic follow-up techniques.

Lung Cancer Screening with Low-Dose CT: What We Have Learned in Two Decades of ITALUNG and What Is Yet to Be Addressed

The ITALUNG trial started in 2004 and compared lung cancer (LC) and other-causes mortality in 55-69 years-aged smokers and ex-smokers who were randomized to four annual chest low-dose CT (LDCT) or usual care. ITALUNG showed a lower LC and cardiovascular mortality in the screened subjects after 13 years of follow-up, especially in women, and produced many ancillary studies. They included recruitment results of a population-based mimicking approach, development of software for computer-aided diagnosis (CAD) and lung nodules volumetry, LDCT assessment of pulmonary emphysema and coronary artery calcifications (CAC) and their relevance to long-term mortality, results of a smoking-cessation intervention, assessment of the radiations dose associated with screening LDCT, and the results of biomarkers assays. Moreover, ITALUNG data indicated that screen-detected LCs are mostly already present at baseline LDCT, can present as lung cancer associated with cystic airspaces, and can be multiple. However, several issues of LC screening are still unaddressed. They include the annual vs. biennial pace of LDCT, choice between opportunistic or population-based recruitment. and between uni or multi-centre screening, implementation of CAD-assisted reading, containment of false positive and negative LDCT results, incorporation of emphysema. and CAC quantification in models of personalized LC and mortality risk, validation of ultra-LDCT acquisitions, optimization of the smoking-cessation intervention. and prospective validation of the biomarkers.

Radiation Exposure to Low-Dose Computed Tomography for Lung Cancer Screening: Should We Be Concerned?

Lung cancer screening (LCS) programs through low-dose Computed Tomography (LDCT) are being implemented in several countries worldwide. Radiation exposure of healthy individuals due to prolonged CT screening rounds and, eventually, the additional examinations required in case of suspicious findings may represent a concern, thus eventually reducing the participation in an LCS program. Therefore, the present review aims to assess the potential radiation risk from LDCT in this setting, providing estimates of cumulative dose and radiation-related risk in LCS in order to improve awareness for an informed and complete attendance to the program. After summarizing the results of the international trials on LCS to introduce the benefits coming from the implementation of a dedicated program, the screening-related and participant-related factors determining the radiation risk will be introduced and their burden assessed. Finally, future directions for a personalized screening program as well as technical improvements to reduce the delivered dose will be presented.

Should We Always Perform Preoperative Chest Computed Tomography in Patients with cT1a Renal Cell Carcinoma?

No definitive criteria regarding the performance of preoperative chest computed tomography (CT) in patients with cT1a renal cell carcinoma (RCC) exists. We aimed to establish an objective standard for the optimal timing of preoperative chest CT in patients with RCC. Data from 890 patients who underwent surgical treatment for RCC between January 2011 and December 2020 were retrospectively collected. The primary endpoint was detection of lung metastasis on chest CT before nephrectomy. A multivariable logistic regression model predicting positive chest CT scans was used. Predictors included preoperative cTN stage, presence of systemic symptoms, Charlson comorbidity index (CCI), platelet count/hemoglobin ratio, albumin/globulin ratio (AGR), and De Ritis ratio. The overall rate of positive chest CT scans before nephrectomy was 3.03% (27/890). Only one patient had lung metastasis before surgery for cT1a. cT stage (≥cT1b), CCI ≥4, and low AGR were associated with a higher risk of positive chest CT scans. The best cutoff value for AGR was 1.39. After 890-sample bootstrap validation, the concordance index was 0.80. The net benefit of the proposed strategy was superior to that of the select-all and select-none strategies according to decision curve analysis. Therefore, when chest CT scans were performed with a risk of a positive result ≥10%, 532 (59.8%) negative chest CT scans could be prevented. Only 24 (2.7%) potentially positive chest CT scans were misdiagnosed. Therefore, we recommend chest CT in patients with ≥cT1b disease, CCI ≥4, and low AGR.

Single CT Appointment for Double Lung and Colorectal Cancer Screening: Is the Time Ripe?

Annual screening of lung cancer (LC) with chest low-dose computed tomography (CT) and screening of colorectal cancer (CRC) with CT colonography every 5 years are recommended by the United States Prevention Service Task Force. We review epidemiological and pathological data on LC and CRC, and the features of screening chest low-dose CT and CT colonography comprising execution, reading, radiation exposure and harm, and the cost effectiveness of the two CT screening interventions. The possibility of combining chest low-dose CT and CT colonography examinations for double LC and CRC screening in a single CT appointment is then addressed. We demonstrate how this approach appears feasible and is already reasonable as an opportunistic screening intervention in 50–75-year-old subjects with smoking history and average CRC risk. In addition to the crucial role Computer Assisted Diagnosis systems play in decreasing the test reading times and the need to educate radiologists in screening chest LDCT and CT colonography, in view of a single CT appointment for double screening, the following uncertainties need to be solved: (1) the schedule of the screening CT; (2) the effectiveness of iterative reconstruction and deep learning algorithms affording an ultra-low-dose CT acquisition technique and (3) management of incidental findings. Resolving these issues will imply new cost-effectiveness analyses for LC screening with chest low dose CT and for CRC screening with CT colonography and, especially, for the double LC and CRC screening with a single-appointment CT.

Impact of low-dose computed tomography (LDCT) screening on lung cancer-related mortality

BACKGROUND

Lung cancer is the most common cause of cancer-related death in the world, however lung cancer screening has not been implemented in most countries at a population level. A previous Cochrane Review found limited evidence for the effectiveness of lung cancer screening with chest radiography (CXR) or sputum cytology in reducing lung cancer-related mortality, however there has been increasing evidence supporting screening with low-dose computed tomography (LDCT).  OBJECTIVES: To determine whether screening for lung cancer using LDCT of the chest reduces lung cancer-related mortality and to evaluate the possible harms of LDCT screening.

SEARCH METHODS

We performed the search in collaboration with the Information Specialist of the Cochrane Lung Cancer Group and included the Cochrane Lung Cancer Group Trial Register, Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library, current issue), MEDLINE (accessed via PubMed) and Embase in our search. We also searched the clinical trial registries to identify unpublished and ongoing trials. We did not impose any restriction on language of publication. The search was performed up to 31 July 2021.  SELECTION CRITERIA: Randomised controlled trials (RCTs) of lung cancer screening using LDCT and reporting mortality or harm outcomes.  DATA COLLECTION AND ANALYSIS: Two review authors were involved in independently assessing trials for eligibility, extraction of trial data and characteristics, and assessing risk of bias of the included trials using the Cochrane RoB 1 tool. We assessed the certainty of evidence using GRADE. Primary outcomes were lung cancer-related mortality and harms of screening. We performed a meta-analysis, where appropriate, for all outcomes using a random-effects model. We only included trials in the analysis of mortality outcomes if they had at least 5 years of follow-up. We reported risk ratios (RRs) and hazard ratios (HRs), with 95% confidence intervals (CIs) and used the I2 statistic to investigate heterogeneity.  MAIN RESULTS: We included 11 trials in this review with a total of 94,445 participants. Trials were conducted in Europe and the USA in people aged 40 years or older, with most trials having an entry requirement of ≥ 20 pack-year smoking history (e.g. 1 pack of cigarettes/day for 20 years or 2 packs/day for 10 years etc.). One trial included male participants only. Eight trials were phase three RCTs, with two feasibility RCTs and one pilot RCT. Seven of the included trials had no screening as a comparison, and four trials had CXR screening as a comparator. Screening frequency included annual, biennial and incrementing intervals. The duration of screening ranged from 1 year to 10 years. Mortality follow-up was from 5 years to approximately 12 years.  None of the included trials were at low risk of bias across all domains. The certainty of evidence was moderate to low across different outcomes, as assessed by GRADE. In the meta-analysis of trials assessing lung cancer-related mortality, we included eight trials (91,122 participants), and there was a reduction in mortality of 21% with LDCT screening compared to control groups of no screening or CXR screening (RR 0.79, 95% CI 0.72 to 0.87; 8 trials, 91,122 participants; moderate-certainty evidence). There were probably no differences in subgroups for analyses by control type, sex, geographical region, and nodule management algorithm. Females appeared to have a larger lung cancer-related mortality benefit compared to males with LDCT screening. There was also a reduction in all-cause mortality (including lung cancer-related) of 5% (RR 0.95, 95% CI 0.91 to 0.99; 8 trials, 91,107 participants; moderate-certainty evidence).  Invasive tests occurred more frequently in the LDCT group (RR 2.60, 95% CI 2.41 to 2.80; 3 trials, 60,003 participants; moderate-certainty evidence). However, analysis of 60-day postoperative mortality was not significant between groups (RR 0.68, 95% CI 0.24 to 1.94; 2 trials, 409 participants; moderate-certainty evidence).  False-positive results and recall rates were higher with LDCT screening compared to screening with CXR, however there was low-certainty evidence in the meta-analyses due to heterogeneity and risk of bias concerns. Estimated overdiagnosis with LDCT screening was 18%, however the 95% CI was 0 to 36% (risk difference (RD) 0.18, 95% CI -0.00 to 0.36; 5 trials, 28,656 participants; low-certainty evidence). Four trials compared different aspects of health-related quality of life (HRQoL) using various measures. Anxiety was pooled from three trials, with participants in LDCT screening reporting lower anxiety scores than in the control group (standardised mean difference (SMD) -0.43, 95% CI -0.59 to -0.27; 3 trials, 8153 participants; low-certainty evidence). There were insufficient data to comment on the impact of LDCT screening on smoking behaviour.  AUTHORS' CONCLUSIONS: The current evidence supports a reduction in lung cancer-related mortality with the use of LDCT for lung cancer screening in high-risk populations (those over the age of 40 with a significant smoking exposure). However, there are limited data on harms and further trials are required to determine participant selection and optimal frequency and duration of screening, with potential for significant overdiagnosis of lung cancer. Trials are ongoing for lung cancer screening in non-smokers.

Deep Learning to Optimize Candidate Selection for Lung Cancer CT Screening: Advancing the 2021 USPSTF Recommendations

Background A deep learning (DL) model to identify lung cancer screening candidates based on their chest radiographs requires external validation with a recent real-world non-U.S. sample. Purpose To validate the DL model and identify added benefits to the 2021 U.S. Preventive Services Task Force (USPSTF) recommendations in a health check-up sample. Materials and Methods This single-center retrospective study included consecutive current and former smokers aged 50-80 years who underwent chest radiography during a health check-up between January 2004 and June 2018. Discrimination performance, including receiver operating characteristic curve analysis and area under the receiver operating characteristic curve (AUC) calculation, of the model for incident lung cancers was evaluated. The added value of the model to the 2021 USPSTF recommendations was investigated for lung cancer inclusion rate, proportion of selected CT screening candidates, and positive predictive value (PPV). Results For model validation, a total of 19 488 individuals (mean age, 58 years ± 6 [SD]; 18 467 [95%] men) and the subset of USPSTF-eligible individuals (n = 7835; mean age, 57 years ± 6; 7699 [98%] men) were assessed, and the AUCs for incident lung cancers were 0.68 (95% CI: 0.62, 0.73) and 0.75 (95% CI: 0.68, 0.81), respectively. In individuals with pack-year information (n = 17 390), when excluding low- and indeterminate-risk categories from the USPSTF-eligible sample, the proportion of selected CT screening candidates was reduced to 35.8% (6233 of 17 390) from 45.1% (7835 of 17 390, P < .001), with three missed lung cancers (0.2%). The cancer inclusion rate (0.3% [53 of 17 390] vs 0.3% [56 of 17 390], P = .85) and PPV (0.9% [53 of 6233] vs 0.7% [56 of 7835], P = .42) remained unaffected. Conclusion An externally validated deep learning model showed the added value to the 2021 U.S. Preventive Services Task Force recommendations for low-dose CT lung cancer screening in reducing the number of screening candidates while maintaining the inclusion rate and positive predictive value for incident lung cancer. © RSNA, 2022 Online supplemental material is available for this article.

Screening for Lung Cancer in Individuals Who Never Smoked: An International Association for the Study of Lung Cancer Early Detection and Screening Committee Report

Screening with low-dose computed tomography of high-risk individuals with a smoking history reduces lung cancer mortality. Current screening guidelines and eligibility criteria can miss more than 50% of lung cancers, and in some geographic areas, such as East Asia, a large proportion of the missed lung cancers are in never-smokers. Although randomized trials revealed the benefits of screening for people who smoke, these trials generally excluded never-smokers. Thus, the feasibility and effectiveness of lung cancer screening of individuals who never smoked are uncertain. Several known and suspected risk factors for lung cancers in never-smokers such as exposure to secondhand smoke, occupational carcinogens, radon, air pollution, and pulmonary diseases, such as chronic obstructive pulmonary disease and interstitial lung diseases, and intrinsic factors, such as age, are well noted. In this regard, knowledge of risk factors may make possible quantification and prediction of lung cancer risk in never smokers. It is worth considering if and how never smokers could be included in population-based screening programs. As the implementation of these programs is challenging in many countries owing to multiple factors and the epidemiologic differences by global regions, these issues will need to be evaluated in each country taking into account various factors, including accuracy of risk assessment and cost-effectiveness of screening in never smokers. This report aims to outline current knowledge on risk factors for lung cancer in never smokers to propose research strategies for this topic and initiate a broader discussion on lung cancer screening of never smokers. Similar considerations can be made in current and ex-smokers, which do not fulfill the current screening inclusion criteria, but otherwise are at increased risk. Although screening of never smokers may in the future be effectively conducted, current evidence to support widespread implementation of this practice is lacking.

Lung Cancer Screening with Low-Dose CT in Smokers: A Systematic Review and Meta-Analysis

Lung cancer continues to be one of the main causes of cancer death in Europe. Low-dose computed tomography (LDCT) has shown high potential for screening of lung cancer in smokers, most recently in two European trials. The aim of this review was to assess lung cancer screening of smokers by LDCT with respect to clinical effectiveness, radiological procedures, quality of life, and changes in smoking behavior. We searched electronic databases in April 2020 for publications of randomized controlled trials (RCT) reporting on lung cancer and overall mortality, lung cancer morbidity, and harms of LDCT screening. A meta-analysis was performed to estimate effects on mortality. Forty-three publications on 10 RCTs were included. The meta-analysis of eight studies showed a statistically significant relative reduction of lung cancer mortality of 12% in the screening group (risk ratio = 0.88; 95% CI: 0.79-0.97). Between 4% and 24% of screening-LDCT scans were classified as positive, and 84-96% of them turned out to be false positive. The risk of overdiagnosis was estimated between 19% and 69% of diagnosed lung cancers. Lung cancer screening can reduce disease-specific mortality in (former) smokers when stringent requirements and quality standards for performance are met.

Personalising lung cancer screening: An overview of risk-stratification opportunities and challenges

Randomised clinical trials have shown the efficacy of computed tomography lung cancer screening, initiating discussions on whether and how to implement population‐based screening programs. Due to smoking behaviour being the primary risk‐factor for lung cancer and part of the criteria for determining screening eligibility, lung cancer screening is inherently risk‐based. In fact, the selection of high‐risk individuals has been shown to be essential in implementing lung cancer screening in a cost‐effective manner. Furthermore, studies have shown that further risk‐stratification may improve screening efficiency, allow personalisation of the screening interval and reduce health disparities. However, implementing risk‐based lung cancer screening programs also requires overcoming a number of challenges. There are indications that risk‐based approaches can negatively influence the trade‐off between individual benefits and harms if not applied thoughtfully. Large‐scale implementation of targeted, risk‐based screening programs has been limited thus far. Consequently, questions remain on how to efficiently identify and invite high‐risk individuals from the general population. Finally, while risk‐based approaches may increase screening program efficiency, efficiency should be balanced with the overall impact of the screening program. In this review, we will address the opportunities and challenges in applying risk‐stratification in different aspects of lung cancer screening programs, as well as the balance between screening program efficiency and impact.

Screening for Lung Cancer With Low-Dose Computed Tomography: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Lung cancer is the leading cause of cancer-related death in the US.

OBJECTIVE

To review the evidence on screening for lung cancer with low-dose computed tomography (LDCT) to inform the US Preventive Services Task Force (USPSTF).

DATA SOURCES

MEDLINE, Cochrane Library, and trial registries through May 2019; references; experts; and literature surveillance through November 20, 2020.

STUDY SELECTION

English-language studies of screening with LDCT, accuracy of LDCT, risk prediction models, or treatment for early-stage lung cancer.

DATA EXTRACTION AND SYNTHESIS

Dual review of abstracts, full-text articles, and study quality; qualitative synthesis of findings. Data were not pooled because of heterogeneity of populations and screening protocols.

MAIN OUTCOMES AND MEASURES

Lung cancer incidence, lung cancer mortality, all-cause mortality, test accuracy, and harms.

RESULTS

This review included 223 publications. Seven randomized clinical trials (RCTs) (N = 86 486) evaluated lung cancer screening with LDCT; the National Lung Screening Trial (NLST, N = 53 454) and Nederlands-Leuvens Longkanker Screenings Onderzoek (NELSON, N = 15 792) were the largest RCTs. Participants were more likely to benefit than the US screening-eligible population (eg, based on life expectancy). The NLST found a reduction in lung cancer mortality (incidence rate ratio [IRR], 0.85 [95% CI, 0.75-0.96]; number needed to screen [NNS] to prevent 1 lung cancer death, 323 over 6.5 years of follow-up) with 3 rounds of annual LDCT screening compared with chest radiograph for high-risk current and former smokers aged 55 to 74 years. NELSON found a reduction in lung cancer mortality (IRR, 0.75 [95% CI, 0.61-0.90]; NNS to prevent 1 lung cancer death of 130 over 10 years of follow-up) with 4 rounds of LDCT screening with increasing intervals compared with no screening for high-risk current and former smokers aged 50 to 74 years. Harms of screening included radiation-induced cancer, false-positive results leading to unnecessary tests and invasive procedures, overdiagnosis, incidental findings, and increases in distress. For every 1000 persons screened in the NLST, false-positive results led to 17 invasive procedures (number needed to harm, 59) and fewer than 1 person having a major complication. Overdiagnosis estimates varied greatly (0%-67% chance that a lung cancer was overdiagnosed). Incidental findings were common, and estimates varied widely (4.4%-40.7% of persons screened).

CONCLUSIONS AND RELEVANCE

Screening high-risk persons with LDCT can reduce lung cancer mortality but also causes false-positive results leading to unnecessary tests and invasive procedures, overdiagnosis, incidental findings, increases in distress, and, rarely, radiation-induced cancers. Most studies reviewed did not use current nodule evaluation protocols, which might reduce false-positive results and invasive procedures for false-positive results.

Screening for Lung Cancer: US Preventive Services Task Force Recommendation Statement

IMPORTANCE

Lung cancer is the second most common cancer and the leading cause of cancer death in the US. In 2020, an estimated 228 820 persons were diagnosed with lung cancer, and 135 720 persons died of the disease. The most important risk factor for lung cancer is smoking. Increasing age is also a risk factor for lung cancer. Lung cancer has a generally poor prognosis, with an overall 5-year survival rate of 20.5%. However, early-stage lung cancer has a better prognosis and is more amenable to treatment.

OBJECTIVE

To update its 2013 recommendation, the US Preventive Services Task Force (USPSTF) commissioned a systematic review on the accuracy of screening for lung cancer with low-dose computed tomography (LDCT) and on the benefits and harms of screening for lung cancer and commissioned a collaborative modeling study to provide information about the optimum age at which to begin and end screening, the optimal screening interval, and the relative benefits and harms of different screening strategies compared with modified versions of multivariate risk prediction models.

POPULATION

This recommendation statement applies to adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years.

EVIDENCE ASSESSMENT

The USPSTF concludes with moderate certainty that annual screening for lung cancer with LDCT has a moderate net benefit in persons at high risk of lung cancer based on age, total cumulative exposure to tobacco smoke, and years since quitting smoking.

RECOMMENDATION

The USPSTF recommends annual screening for lung cancer with LDCT in adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years. Screening should be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery. (B recommendation) This recommendation replaces the 2013 USPSTF statement that recommended annual screening for lung cancer with LDCT in adults aged 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years.

Lung Cancer Screening, Version 3.2018, NCCN Clinical Practice Guidelines in Oncology

Lung cancer is the leading cause of cancer-related mortality in the United States and worldwide. Early detection of lung cancer is an important opportunity for decreasing mortality. Data support using low-dose computed tomography (LDCT) of the chest to screen select patients who are at high risk for lung cancer. Lung screening is covered under the Affordable Care Act for individuals with high-risk factors. The Centers for Medicare & Medicaid Services (CMS) covers annual screening LDCT for appropriate Medicare beneficiaries at high risk for lung cancer if they also receive counseling and participate in shared decision-making before screening. The complete version of the NCCN Guidelines for Lung Cancer Screening provides recommendations for initial and subsequent LDCT screening and provides more detail about LDCT screening. This manuscript focuses on identifying patients at high risk for lung cancer who are candidates for LDCT of the chest and on evaluating initial screening findings.

Implementation planning for lung cancer screening in China

Lung cancer is the leading cause of cancer-related deaths in China, with over 690 000 lung cancer deaths estimated in 2018. The mortality has increased about five-fold from the mid-1970s to the 2000s. Lung cancer low-dose computerized tomography (LDCT) screening in smokers was shown to improve survival in the US National Lung Screening Trial, and more recently in the European NELSON trial. However, although the predominant risk factor, smoking contributes to a lower fraction of lung cancers in China than in the UK and USA. Therefore, it is necessary to establish Chinese-specific screening strategies. There have been 23 associated programmes completed or still ongoing in China since the 1980s, mainly after 2000; and one has recently been planned. Generally, their entry criteria are not smoking-stringent. Most of the Chinese programmes have reported preliminary results only, which demonstrated a different high-risk subpopulation of lung cancer in China. Evidence concerning LDCT screening implementation is based on results of randomized controlled trials outside China. LDCT screening programmes combining tobacco control would produce more benefits. Population recruitment (e.g. risk-based selection), screening protocol, nodule management and cost-effectiveness are discussed in detail. In China, the high-risk subpopulation eligible for lung cancer screening has not as yet been confirmed, as all the risk parameters have not as yet been determined. Although evidence on best practice for implementation of lung cancer screening has been accumulating in other countries, further research in China is urgently required, as China is now facing a lung cancer epidemic.

Cancer risk assessment in modern radiotherapy workflow with medical big data

Modern radiotherapy (RT) is being enriched by big digital data and intensive technology. Multimodality image registration, intelligence-guided planning, real-time tracking, image-guided RT (IGRT), and automatic follow-up surveys are the products of the digital era. Enormous digital data are created in the process of treatment, including benefits and risks. Generally, decision making in RT tries to balance these two aspects, which is based on the archival and retrieving of data from various platforms. However, modern risk-based analysis shows that many errors that occur in radiation oncology are due to failures in workflow. These errors can lead to imbalance between benefits and risks. In addition, the exact mechanism and dose-response relationship for radiation-induced malignancy are not well understood. The cancer risk in modern RT workflow continues to be a problem. Therefore, in this review, we develop risk assessments based on our current knowledge of IGRT and provide strategies for cancer risk reduction. Artificial intelligence (AI) such as machine learning is also discussed because big data are transforming RT via AI.

Identification of a three-miRNA signature as a blood-borne diagnostic marker for early diagnosis of lung adenocarcinoma

Background

The subtypes of NSCLC have unique characteristics of pathogenic mechanism and responses to targeted therapies. Thus, non-invasive markers for diagnosis of different subtypes of NSCLC at early stage are needed.

Results

Based on the results from the screening and validation process, 3 miRNAs (miR-532, miR-628-3p and miR-425-3p) were found to display significantly different expression levels in early-stage lung adenocarcinoma, as compared to those in healthy controls. ROC analysis showed that the miRNA–based biomarker could distinguish lung adenocarcinoma from healthy controls with high AUC (0.974), sensitivity (91.5%), and specificity (97.8%). Importantly, these three miRNAs could also distinguish lung adenocarcinoma from lung benigh diseases and other subtypes of lung cancer.

Methods

Two hundreds and one early-stage lung adenocarcinoma cases and one hundreds seventy eight age- and sex-matched healthy controls were recruited to this study. We screened the differentially expressed plasma miRNAs using TaqMan Low Density Arrays (TLDA) followed by three-phase qRT-PCR validation. A risk score model was established to evaluate the diagnostic value of the plasma miRNA profiling system.

Conclusions

Taken together, these findings suggest that the 3 miRNA–based biomarker might serve as a novel non-invasive approach for diagnosis of early-stage lung adenocarcinoma.

Lung densitometry: why, how and when

Lung densitometry assesses with computed tomography (CT) the X-ray attenuation of the pulmonary tissue which reflects both the degree of inflation and the structural lung abnormalities implying decreased attenuation, as in emphysema and cystic diseases, or increased attenuation, as in fibrosis. Five reasons justify replacement with lung densitometry of semi-quantitative visual scales used to measure extent and severity of diffuse lung diseases: (I) improved reproducibility; (II) complete vs. discrete assessment of the lung tissue; (III) shorter computation times; (IV) better correlation with pathology quantification of pulmonary emphysema; (V) better or equal correlation with pulmonary function tests (PFT). Commercially and open platform software are available for lung densitometry. It requires attention to technical and methodological issues including CT scanner calibration, radiation dose, and selection of thickness and filter to be applied to sections reconstructed from whole-lung CT acquisition. Critical is also the lung volume reached by the subject at scanning that can be measured in post-processing and represent valuable information per se. The measurements of lung density include mean and standard deviation, relative area (RA) at -970, -960 or -950 Hounsfield units (HU) and 1st and 15th percentile for emphysema in inspiratory scans, and RA at -856 HU for air trapping in expiratory scans. Kurtosis and skewness are used for evaluating pulmonary fibrosis in inspiratory scans. The main indication for lung densitometry is assessment of emphysema component in the single patient with chronic obstructive pulmonary diseases (COPD). Additional emerging applications include the evaluation of air trapping in COPD patients and in subjects at risk of emphysema and the staging in patients with lymphangioleiomyomatosis (LAM) and with pulmonary fibrosis. It has also been applied to assess prevalence of smoking-related emphysema and to monitor progression of smoking-related emphysema, alpha1 antitrypsin deficiency emphysema, and pulmonary fibrosis. Finally, it is recommended as end-point in pharmacological trials of emphysema and lung fibrosis.

Lung cancer screening with ultra-low dose CT using full iterative reconstruction

PURPOSE

To investigate the diagnostic capability of ultra-low-dose CT (ULDCT) with full iterative reconstruction (f-IR) for lung cancer screening.

MATERIALS AND METHODS

All underwent ULDCT and/or low-dose CT (LD-CT) on a 320-detector scanner. ULDCT images were reconstructed with f-IR. We qualitatively and quantitatively studied 95 nodules in 69 subjects. Two radiologists classified the nodules on ULDCT images as solid-, part-solid-, and pure ground-glass (PGG) and recorded their mean size. Their findings were compared with the reference standard. The observer performance study included 7 other radiologists and 35 subjects with- and 15 without nodules. The results were analyzed by AFROC analysis.

RESULTS

In the qualitative study, the kappa values between observers 1 and 2, respectively, and the reference standard were 0.70 and 0.83; the intra-class correlation coefficients for the nodule diameter between the reference standard and their measurements were 0.84 and 0.90. The 95% confidence interval (CI) for the area under the curve (AUC) difference for nodule detection on LDCT and ULDCT was -0.03 to 0.07. The 95% CI crossed the 0 difference in the AUC but not the pre-defined non-inferiority margin of -0.08.

CONCLUSION

The diagnostic ability of ULDCT using f-IR is comparable to LDCT.

MicroRNA-200 Family Profile: A Promising Ancillary Tool for Accurate Cancer Diagnosis

Cancer is one of the most threatening diseases in the world and great interests have been paid to discover accurate and noninvasive methods for cancer diagnosis. The value of microRNA-200 (miRNA-200, miR-200) family has been revealed in many studies. However, the results from various studies were inconsistent, and thus a meta-analysis was designed and performed to assess the overall value of miRNA200 in cancer diagnosis. Relevant studies were searched electronically from the following databases: PubMed, Embase, Web of Science, the Cochrane Library, and Chinese National Knowledge Infrastructure. Keyword combined with “miR-200,” “cancer,” and “diagnosis” in any fields was used for searching relevant studies. Then, the pooled sensitivity, specificity, area under the curve (AUC), and partial AUC were calculated using the random-effects model. Heterogeneity among individual studies was also explored by subgroup analyses. A total of 28 studies from 18 articles with an overall sample size of 3676 subjects (2097 patients and 1579 controls) were included in this meta-analysis. The overall sensitivity and specificity with 95% confidence intervals (95% CIs) are 0.709 (95% CI: 0.657–0.755) and 0.667 (95% CI: 0.617–0.713), respectively. Additionally, AUC and partial AUC for the pooled data is 0.735 and 0.627, respectively. Subgroup analyses revealed that using miRNA-200 family for cancer diagnosis is more effective in white than in Asian ethnic groups. In addition, cancer diagnosis by miRNA using circulating specimen is more effective than that using noncirculating specimen. Finally, miRNA is more accurate in diagnosing endometrial cancer than other types of cancer, and some miRNA family members (miR-200b and miR-429) have superior diagnostic accuracy than other miR-200 family members. In conclusion, the profiling of miRNA-200 family is likely to be a valuable tool in cancer detection and diagnosis.

Insights into the application of let-7 family as promising biomarker in cancer screening

Cancer is a leading cause of death worldwide with its low 5-year survival rate. Studies on the accuracy of let-7 family for human cancers have inconsistent conclusions, leading us to conduct this meta-analysis. This meta-analysis comprised of 11 studies from eight articles involving 805 cancer patients and 483 controls. The pooled parameters were as follows: sensitivity, 77 % (95 % confidence interval (CI) 73-81 %); specificity, 80 % (95 % CI 68-88 %); positive likelihood ratio (PLR), 3.8; negative likelihood ratio (NLR), 0.29; and diagnostic odds ratio (DOR) 13.0. In addition, we plotted the SROC and calculated the area under the curve (AUC) of 0.81 (95 % CI 0.78-0.84), which indicated a relatively high descriptive accuracy. In summary, our data suggested that let-7 family might be applied in noninvasive screening tests for human cancers, which needed to be validated in further large-scale studies.

MicroRNA-145 as ideal biomarker for the diagnosis of various carcinomas

Increasing evidences indicated that microRNAs (miRNAs) can serve as a noninvasive biomarker with a high sensitivity and specificity for the early diagnosis of various cancers, among which, microRNA-145 (miRNA-145, miR-145) was verified to have strong relationship to irregular apoptosis, thus making it useful in the early detection of cancers. However, contradictory results on its diagnostic accuracy and reliability are still existed in individual studies. Therefore, we conducted this meta-analysis of the relevant published literatures to systematically evaluate the diagnostic value of miR-145 in the prediction of cancers. The sensitivity and specificity of the included studies were used to construct the summary receiver operator characteristic (SROC) curve and calculate the area under the SROC curve (AUC). All analyses were performed using the STATA 12.0 software. Thirteen studies from nine articles were involved in our meta-analysis. The pooled parameters calculated from all studies are as follows: sensitivity, 0.71 (95% confidence interval (CI) 0.59-0.81); specificity, 0.75 (95% CI 0.66-0.83); positive likelihood ratio (PLR), 2.9 (95% CI 1.9-4.4); negative likelihood ratio (NLR), 0.38 (95% CI 0.25-0.58); and diagnostic odds ratio (DOR), 8 (95% CI 3-17). In addition, subgroup analyses based on ethnicity suggested that miR-145 as a biomarker on the detection of cancers for Caucasian population showed a higher sensitivity and specificity than for Asian population. In conclusion, the current meta-analysis showed that miR-145 holds a high accuracy in distinguishing cancer patients from healthy controls with noninvasiveness and high efficiency. However, large-scale prospective studies and additional improvements are urgently needed to confirm our findings and its utilization for routine clinical diagnosis in future.

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.

Epidemiology of lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Ever since a lung cancer epidemic emerged in the mid-1900 s, the epidemiology of lung cancer has been intensively investigated to characterize its causes and patterns of occurrence. This report summarizes the key findings of this research.

METHODS

A detailed literature search provided the basis for a narrative review, identifying and summarizing key reports on population patterns and factors that affect lung cancer risk.

RESULTS

Established environmental risk factors for lung cancer include smoking cigarettes and other tobacco products and exposure to secondhand tobacco smoke, occupational lung carcinogens, radiation, and indoor and outdoor air pollution. Cigarette smoking is the predominant cause of lung cancer and the leading worldwide cause of cancer death. Smoking prevalence in developing nations has increased, starting new lung cancer epidemics in these nations. A positive family history and acquired lung disease are examples of host factors that are clinically useful risk indicators. Risk prediction models based on lung cancer risk factors have been developed, but further refinement is needed to provide clinically useful risk stratification. Promising biomarkers of lung cancer risk and early detection have been identified, but none are ready for broad clinical application.

CONCLUSIONS

Almost all lung cancer deaths are caused by cigarette smoking, underscoring the need for ongoing efforts at tobacco control throughout the world. Further research is needed into the reasons underlying lung cancer disparities, the causes of lung cancer in never smokers, the potential role of HIV in lung carcinogenesis, and the development of biomarkers.

XAGE-1a and XAGE-1d are potential biomarkers of lung squamous cell carcinoma

BACKGROUND

Lung cancer is the leading cause of cancer deaths worldwide. We evaluated the diagnostic potential of sera XAGE-1a and XAGE-1d in lung cancer, both of which are variants of the X antigen family, member 1.

METHODS

The expression levels of XAGE-1a and XAGE-1d in cell lines were determined using western blot analysis. Competitive ELISA was used to analyze XAGE-1a and XAGE-1d levels in culture supernatants and sera from 194 lung cancer patients and 194 healthy sex- and age-group-matched controls. To evaluate the diagnostic performance of these proteins, we also analyzed carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA 21-1) in culture supernatants and 388 sera using commercial ELISA kits.

RESULTS

XAGE-1a and XAGE-1d proteins were expressed in both breast cancer and lung cancer cell lines, but they were only secreted by the latter. The areas under the curves (AUCs) for XAGE-1a and XAGE-1d were 0.787 and 0.806, respectively. The cutoff values (sensitivity, specificity) for XAGE-1a and XAGE-1d were 1.62 ng/ml (0.866, 0.572) and 2.51 ng/ml (0.871, 0.613), respectively. The diagnostic performance was improved for patients with squamous cell carcinoma. The AUC values for XAGE-1a and XAGE-1d for patients with squamous cell carcinoma versus a group containing all healthy participants and patients with any illness other than squamous cell carcinoma were similar to those for CEA and CYFRA 21-1. Better performance (AUC: 0.914) for all patients was obtained when using a combination of four markers (Random Forest).

CONCLUSIONS

Sera XAGE-1a and XAGE-1d are potential biomarkers for lung cancer; they display a diagnostic performance comparable to that of CEA or CYFRA 21-1. Further studies are needed to evaluate the diagnostic and prognostic potential of XAGE-1a and XAGE-1d in lung cancer.

Dose exposure in the ITALUNG trial of lung cancer screening with low-dose CT

Few data are available on the effective dose received by participants in lung cancer screening programmes with low-dose CT (LDCT). We report the collective effective dose delivered to 1406 current or former smokers enrolled in the ITALUNG trial who completed 4 annual LDCT examinations and related further investigations including follow-up LDCT, 2-[(18)F]flu-2-deoxy-d-glucose positron emission tomography (FDG-PET) or CT-guided fine needle aspiration biopsy (FNAB). Using the air CT dose index and Monte Carlo simulations on an anthropomorphic phantom, the whole-body effective dose associated with LDCT was determined for the eight CT scanners used in the trial. A value of 7 mSv was assigned to FDG-PET while the measured mean effective dose of CT-guided FNAB was 1.5 mSv. The mean collective effective dose in the 1406 subjects ranged between 8.75 and 9.36 Sv and the mean effective dose to the single subject over 4 years was between 6.2 and 6.8 mSv (range 1.7-21.5 mSv) according to the cranial-caudal length of the LDCT volume. 77.4% of the dose was owing to annual LDCT and 22.6% to further investigations. Considering the nominal risk coefficients for stochastic effects after exposure to low-dose radiation according to the National Radiological Protection Board, International Commission on Radiological Protection (ICRP) 60, ICRP103 and Biological Effects of Ionizing Radiation VII, the mean number of radiation-induced cancers ranged between 0.12 and 0.33 per 1000 subjects. The individual effective dose to participants in a 4-year lung cancer screening programme with annual LDCT is very low and about one-third of the effective dose that is associated with natural background radiation and diagnostic radiology in the same time period.

Screening for lung cancer using low-dose spiral CT: 10 years later, state of the art

Ten years after the first papers on this subject, this editorial represents a brief review on lung cancer screening with low-dose spiral CT. The aim is to present the main theoretical and practical problems related to lung cancer screening, the historical background and results of observational studies and the main ongoing randomised controlled trials. In particular, the National Lung Screening Trial (NLST), which was interrupted early, is discussed. The opinion of the authors is that too many questions are still awaiting an answer.

Identification of ten serum microRNAs from a genome-wide serum microRNA expression profile as novel noninvasive biomarkers for nonsmall cell lung cancer diagnosis

The detection of nonsmall cell lung cancer (NSCLC) at an early stage presents a daunting challenge due to the lack of a specific noninvasive marker. The discovery of microRNAs (miRNAs), particularly those found in serum, has opened a new avenue for tumor diagnosis. To determine whether the expression profile of serum miRNAs can serve as a NSCLC fingerprint, we performed Taqman probe-based quantitative RT-PCR assay to selected differentially expressed serum miRNAs from a sample set including 400 NSCLC cases and 220 controls, and risk score analysis to evaluate the diagnostic value of the serum miRNA profiling system. After a two-phase selection and validation process, 10 miRNAs were found to have significantly different expression levels in NSCLC serum samples compared with the control serum samples. Risk score analysis showed that this panel of miRNAs was able to distinguish NSCLC cases from controls with high sensitivity and specificity. Under ROC curves, the AUC for tumor identification in training set and validation set were 0.966 and 0.972, respectively. Furthermore, the expression profile of the 10-serum miRNAs was correlated with the stage of NSCLC patients, especially in younger patients and patients with current smoking habits. More importantly, the serum miRNA-based biomarker for early NSCLC detection was supported by a retrospective analysis in which the 10-serum miRNA profile could accurately classify serum samples collected up to 33 months ahead of the clinical NSCLC diagnosis. Taken together, we demonstrate that the profiling of 10-serum miRNAs provides a novel noninvasive biomarker for NSCLC diagnosis.

Lung cancer risk prediction to select smokers for screening CT--a model based on the Italian COSMOS trial

Screening with low-dose helical computed tomography (CT) has been shown to significantly reduce lung cancer mortality but the optimal target population and time interval to subsequent screening are yet to be defined. We developed two models to stratify individual smokers according to risk of developing lung cancer. We first used the number of lung cancers detected at baseline screening CT in the 5,203 asymptomatic participants of the COSMOS trial to recalibrate the Bach model, which we propose using to select smokers for screening. Next, we incorporated lung nodule characteristics and presence of emphysema identified at baseline CT into the Bach model and proposed the resulting multivariable model to predict lung cancer risk in screened smokers after baseline CT. Age and smoking exposure were the main determinants of lung cancer risk. The recalibrated Bach model accurately predicted lung cancers detected during the first year of screening. Presence of nonsolid nodules (RR = 10.1, 95% CI = 5.57-18.5), nodule size more than 8 mm (RR = 9.89, 95% CI = 5.84-16.8), and emphysema (RR = 2.36, 95% CI = 1.59-3.49) at baseline CT were all significant predictors of subsequent lung cancers. Incorporation of these variables into the Bach model increased the predictive value of the multivariable model (c-index = 0.759, internal validation). The recalibrated Bach model seems suitable for selecting the higher risk population for recruitment for large-scale CT screening. The Bach model incorporating CT findings at baseline screening could help defining the time interval to subsequent screening in individual participants. Further studies are necessary to validate these models.

Participation bias in a randomised trial of screening for lung cancer

INTRODUCTION

Participation bias might affect the results and the representability of randomised controlled trials. We investigated the degree of socio-demographic and psychosocial participation bias in the Danish Lung Cancer Screening Trial (DLCST).

METHODS

In DLCST the questionnaire COS-LC (Consequences of Screening in Lung Cancer) was used to measure the psychosocial aspects of screening. To investigate a difference with a comparable representative sample from the Danish population, we sent out an inclusion questionnaire to 3999 Danes in the age from 50 to 70 years randomly selected from the Central National Register. Those who completed the inclusion questionnaire and met the inclusion criteria from DLCST received the COS-LC. Those who completed the COS-LC-and thus formed a population sample comparable to DLCST - were compared to the DLCST participants on socio-demographics and psychosocial measures.

RESULTS

Participation rates were high among the comparable population sample: 75.3% completed the inclusion questionnaire and 77.4% of those who were eligible completed the COS-LC. The analyses revealed differences between the DLCST participants and the comparable population sample in the following socio-demographic aspects: social group, living alone, gender, age and geographical area. DLCST participants reported less negative psychosocial aspects than the comparable population sample.

CONCLUSION

The present study has shown substantial socio-demographic and psychosocial participation bias in DLCST.

Circulating microRNAs: a novel class of biomarkers to diagnose and monitor human cancers

Specific and sensitive non-invasive biomarkers for the detection of human epithelial malignancies are urgently required to reduce the worldwide morbidity and mortality caused by cancer. MicroRNAs (miRNAs) are 19-24 nt noncoding RNAs that are frequently dysregulated in cancer and have shown great promise as tissue-based markers for cancer classification. Once thought to be unstable RNA molecules, miRNAs are now shown to be stably expressed in serum, plasma, urine, saliva, and other body fluids. Moreover, the unique expression patterns of these circulating miRNAs are correlated with certain human diseases, including various types of cancer. Therefore, tumor-derived miRNAs in serum or plasma are emerging as novel blood-based fingerprints for the detection of human cancers, especially at an early stage. This review presented newly uncovered cellular and molecular mechanisms of the sources and stability of circulating miRNAs, revealing their great potential as a class of highly specific and sensitive biomarkers for tumor classification and prognostication. Meanwhile, this review also addressed certain critical issues that hinder the wide application of this new approach. Some potential challenges for the transition of circulating miRNAs from a research setting to a clinical application were also highlighted, with a future perspective of the incorporation of circulating miRNAs in the field of clinical oncology, especially their great potential from diagnostic to prognostic and predictive applications.

Screening for lung cancer: are we there yet?

PURPOSE OF REVIEW

In lung cancer screening with low-dose spiral computed tomography (LDCT), the proportion of stage I disease is 50-85%, and the survival rate for resected stage I disease can exceed 90%, but proof of real benefit in terms of lung cancer mortality reduction must come from the several randomized trials underway in Europe and in the USA. Our purpose is to update the readers on recent progress in medical knowledge in this field.

RECENT FINDINGS

Relevant novelties regarding technical and collateral aspects of lung cancer screening have been made available, covering the performance of detection systems and nodule evaluation protocols, means to increase cost-effectiveness, insight into the biology of lung cancer, promotion of minimally invasive and lung-sparing surgical options, effects of screening on smoking habits and early follow-up findings in one randomized trial of LDCT vs. clinical review.

CONCLUSION

Early follow-up data suggest that the effect of screening with LDCT on mortality might be smaller than expected, but definitive follow-up data are still awaited from all ongoing randomized trials. Lung cancer screening research is yielding a relevant body of medical knowledge that will be beneficial for other smoking-related diseases and contribute to a better understanding of lung cancer biology.

Consequences of screening in lung cancer: development and dimensionality of a questionnaire

OBJECTIVE

The objective of this study was to extend the Consequences of Screening (COS) Questionnaire for use in a lung cancer screening by testing for comprehension, content coverage, dimensionality, and reliability.

METHODS

In interviews, the suitability, content coverage, and relevance of the COS were tested on participants in a lung cancer screening program. The results were thematically analyzed to identify the key consequences of abnormal and false-positive screening results. Item Response Theory and Classical Test Theory were used to analyze data. Dimensionality, objectivity, and reliability were established by item analysis, examining the fit between item responses and Rasch models.

RESULTS

Eight themes specifically relevant for participants in lung cancer screening results were identified: "self-blame,""focus on symptoms,""stigmatization,""introvert,""harm of smoking,""impulsivity,""empathy," and "regretful of still smoking." Altogether, 26 new items for part I and 16 new items for part II were generated. These themes were confirmed to fit a partial-credit Rasch model measuring different constructs including several of the new items.

CONCLUSION

In conclusion, the reliability and the dimensionality of a condition-specific measure with high content validity for persons having abnormal or false-positive lung cancer screening results have been demonstrated. This new questionnaire called Consequences of Screening in Lung Cancer (COS-LC) covers in two parts the psychosocial experience in lung cancer screening. Part I: "anxiety,""behavior,""dejection,""sleep,""self-blame,""focus on airway symptoms,""stigmatization,""introvert," and "harm of smoking." Part II: "calm/relax,""social network,""existential values,""impulsivity,""empathy," and "regretful of still smoking."

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.

The Danish randomized lung cancer CT screening trial--overall design and results of the prevalence round

INTRODUCTION

Lung cancer screening with low dose computed tomography (CT) has not yet been evaluated in randomized clinical trials, although several are underway.

METHODS

In The Danish Lung Cancer Screening Trial, 4104 smokers and previous smokers from 2004 to 2006 were randomized to either screening with annual low dose CT scans for 5 years or no screening. A history of cigarette smoking of at least 20 pack years was required. All participants have annual lung function tests, and questionnaires regarding health status, psychosocial consequences of screening, smoking habits, and smoking cessation. Baseline CT scans were performed in 2052 participants. Pulmonary nodules were classified according to size and morphology: (1) Nodules smaller than 5 mm and calcified (benign) nodules were tabulated, (2) Noncalcified nodules between 5 and 15 mm were rescanned after 3 months. If the nodule increased in size or was larger than 15 mm the participant was referred for diagnostic workup.

RESULTS

At baseline 179 persons showed noncalcified nodules larger than 5 mm, and most were rescanned after 3 months: The rate of false-positive diagnoses was 7.9%, and 17 individuals (0.8%) turned out to have lung cancer. Ten of these had stage I disease. Eleven of 17 lung cancers at baseline were treated surgically, eight of these by video assisted thoracic surgery resection.

CONCLUSIONS

Screening may facilitate minimal invasive treatment and can be performed with a relatively low rate of false-positive screen results compared with previous studies on lung cancer screening.

Screening for lung cancer

OBJECTIVE

The purpose of our review is to discuss the current state of lung cancer screening using CT in the context of defined criteria for effective screening.

CONCLUSION

Although there are hopeful developments in lung cancer screening, a number of unresolved issues must be answered before adopting screening on a large scale. Currently no data exist to suggest that lung cancer screening with CT will result in a decrease in lung cancer mortality.

Preoperative noncontrast chest computed tomography identifies potential aortic emboli

BACKGROUND

Intraoperative epiaortic scanning identifies aortic atheroma. Avoiding atheroma manipulation reduces cerebral vascular accidents (CVA). Unfortunately, epiaortic scanning can only be performed after the time of sternotomy. We sought to determine whether (1) preoperative noncontrast chest computed tomography (CT) identifies areas of aorta at risk for embolization in high-risk patients, and (2) operative strategies designed at the reduction of aortic manipulation of these areas can reduce permanent strokes.

METHODS

The rate of permanent strokes was examined at a single institution between two time periods using the chi2 method. From January 2002 through June 2003 (pre-CT) 230 patients underwent elective cardiac procedures. All patients received routine intraoperative transesophageal echocardiography but only selective epiaortic scanning. From July 2003 through December 2005 (post-CT), 273 patients underwent cardiac operations and 114 patients at high risk for a stroke (history of CVA or transient ischemic attack, peripheral vascular disease, end-stage renal disease, age >70 years old or calcifications on cardiac catheterization) also received a preoperative noncontrast chest CT.

RESULTS

In the pre-CT period, 7 patients received epiaortic scans that resulted in a change in operative strategy in only 1 patient. In the post-CT period, the 114 CT scans identified 20 patients with significant calcifications in the ascending aorta. Operative strategy was altered in 19 patients, including 12 axillary artery cannulations, four off-pump, no-touch aorta coronary bypasses, and three ascending aortic replacements. The CVA rate was 3.04% in the pre-CT period and 0.73% in the post-CT period (p = 0.05).

CONCLUSIONS

Aggressive screening and avoidance of ascending aortic atheroma reduces stroke. Preoperative CT scans in patients at high risk may help identify aortic areas at risk before entering the operating room, lead to more thorough screening in the operating room, and result in a more aggressive strategy to avoid calcified areas.

Prediction of lung cancer using volatile biomarkers in breath

BACKGROUND

Normal metabolism generates several volatile organic compounds (VOCs) that are excreted in the breath (e.g. alkanes). In patients with lung cancer, induction of high-risk cytochrome p450 genotypes may accelerate catabolism of these VOCs, so that their altered abundance in breath may provide biomarkers of lung cancer.

METHODS

VOCs in 1.0 L alveolar breath were analyzed in 193 subjects with primary lung cancer and 211 controls with a negative chest CT. Subjects were randomly assigned to a training set or to a prediction set in a 2:1 split. A fuzzy logic model of breath biomarkers of lung cancer was constructed in the training set and then tested in subjects in the prediction set by generating their typicality scores for lung cancer.

RESULTS

Mean typicality scores employing a 16 VOC model were significantly higher in lung cancer patients than in the control group (p<0.0001 in all TNM stages). The model predicted primary lung cancer with 84.6% sensitivity, 80.0% specificity, and 0.88 area under curve (AUC) of the receiver operating characteristic (ROC) curve. Predictive accuracy was similar in TNM stages 1 through 4, and was not affected by current or former tobacco smoking. The predictive model achieved near-maximal performance with six breath VOCs, and was progressively degraded by random classifiers. Predictions with fuzzy logic were consistently superior to multilinear analysis. If applied to a population with 2% prevalence of lung cancer, a screening breath test would have a negative predictive value of 0.985 and a positive predictive value of 0.163 (true positive rate =0.277, false positive rate =0.029).

CONCLUSIONS

A two-minute breath test predicted lung cancer with accuracy comparable to screening CT of chest. The accuracy of the test was not affected by TNM stage of disease or tobacco smoking. Alterations in breath VOCs in lung cancer were consistent with a non-linear pathophysiologic process, such as an off-on switch controlling high-risk cytochrome p450 activity. Further research is needed to determine if detection of lung cancer with this test will reduce mortality.