Screening for lung cancer with low-dose spiral computed tomography

Lung cancer screening: nodule identification and characterization

The accurate identification and characterization of small pulmonary nodules at low-dose CT is an essential requirement for the implementation of effective lung cancer screening. Individual reader detection performance is influenced by nodule characteristics and technical CT parameters but can be improved by training, the application of CT techniques, and by computer-aided techniques. However, the evaluation of nodule detection in lung cancer screening trials differs from the assessment of individual readers as it incorporates multiple readers, their inter-observer variability, reporting thresholds, and reflects the program accuracy in identifying lung cancer. Understanding detection and interpretation errors in screening trials aids in the implementation of lung cancer screening in clinical practice. Indeed, as CT screening moves to ever lower radiation doses, radiologists must be cognisant of new technical challenges in nodule assessment. Screen detected lung cancers demonstrate distinct morphological features from incidentally or symptomatically detected lung cancers. Hence characterization of screen detected nodules requires an awareness of emerging concepts in early lung cancer appearances and their impact on radiological assessment and malignancy prediction models. Ultimately many nodules remain indeterminate, but further imaging evaluation can be appropriate with judicious utilization of contrast enhanced CT or MRI techniques or functional evaluation by PET-CT.

Extrapulmonary neoplasms in lung cancer screening

A significant reduction in lung cancer specific mortality rate was demonstrated by the National Lung Screening Trial (NLST) in participants who had annual low-dose computed tomography (LDCT) screening. In addition to early detection of lung cancer, lung cancer screening (LCS) provides an opportunity to detect cardiovascular disease, pulmonary disease (such as chronic obstructive pulmonary disease and interstitial lung disease), and extrapulmonary neoplasms, such as thyroid, breast, kidney, liver, esophageal, pancreatic and mediastinal tumors. Considering the fact that 22.3% of the certified deaths in the computed tomography (CT) arm of the NLST trial were due to extrapulmonary malignancies, compared to 22.9% of deaths from lung cancer, it is possible that early diagnosis and treatment of clinically significant incidental findings may further decrease morbidity and mortality in screening participants. In this article we review prevalence, clinical relevance and management of incidentally detected extrapulmonary malignancies.

How asymptomatic are early cancer patients of five organs based on registry data in Japan

BACKGROUND

One reason for the low cancer screening rate in Japan is that people are not concerned about cancer if they do not have symptoms.

METHODS

The authors retrospectively analyzed 18,405 cancer patients using hospital-based cancer registry data collected between 2007 and 2013 at the 13 hospitals of Shimane Prefecture, Japan. The symptomatic rates of five cancers (stomach, colorectal, lung, breast, and cervix) at each stage and the time of early diagnosis were investigated. The early detection rates of symptomatic and asymptomatic individuals were investigated.

RESULTS

The percentages of symptomatic cases tended to increase with progressive stages. The odds ratio (OR) of stage IV compared with that of stage I was 12.23 for stomach, 7.21 for colorectal, 16.91 for lung, 10.30 for breast, and 51.62 for cervical cancer. The proportions of early symptomatic cases at the time of diagnosis were low. Compared with the percentage of early symptomatic cases of stomach cancer of 25.5%, the percentage of lung cancer was the lowest, at 8.2% (OR 0.26), and the percentage of breast cancer was the highest, at 30.2% (OR 1.26). The percentages of early symptomatic cases of colorectal and cervical cancer were 18.9% (OR 0.68) and 19.9% (OR 0.73), respectively. The early detection rates of the asymptomatic and symptomatic groups were 77.6 and 36.1%, respectively.

CONCLUSION

Cancer registry data indicate that early cancers are asymptomatic, and once symptoms appear, treatment may not be effective. Policy makers should inform people of the necessity of cancer screening before they have symptoms.

Multifactorial Analysis of Mortality in Screening Detected Lung Cancer

We hypothesized that severity of coronary artery calcification (CAC), emphysema, muscle mass, and fat attenuation can help predict mortality in patients with lung cancer participating in the National Lung Screening Trial (NLST). Following regulatory approval from the Cancer Data Access System (CDAS), all patients diagnosed with lung cancer at the time of the screening study were identified. These subjects were classified into two groups: survivors and nonsurvivors at the conclusion of the NLST trial. These groups were matched based on their age, gender, body mass index (BMI), smoking history, lung cancer stage, and survival time. CAC, emphysema, muscle mass, and subcutaneous fat attenuation were quantified on baseline low-dose chest CT (LDCT) for all patients in both groups. Nonsurvivor group had significantly greater CAC, decreased muscle mass, and higher fat attenuation compared to the survivor group (p < 0.01). No significant difference in severity of emphysema was noted between the two groups (p > 0.1). We thus conclude that it is possible to create a quantitative prediction model for lung cancer mortality for subjects with lung cancer detected on screening low-dose CT (LDCT).

Risk factors for pulmonary nodules in north China: A prospective cohort study

OBJECTIVES

Pulmonary nodules have become common incidental findings with the widespread use of computed tomography (CT) technology. Such nodules have the potential to become early lung cancer lesions, so understanding more about factors that may be associated with them is important.

MATERIALS AND METHODS

The present work was based on a large prospective cohort comprising 32,438 participants in Hebei Province (China) between January 2014 and March 2016. Participants aged 40-75 years completed a questionnaire, underwent low-dose CT (LDCT), and were followed up to March 2017. Grouped by the results of LDCT, normal participants and those with pulmonary nodules were included in the data analysis.

RESULTS

In total 7752 subjects were included in this study, of whom 2040 (26.32%) were pulmonary nodule patients. Older age, current smoking status (hazard ratio (HR) = 1.43, 95% confidence interval (95%CI): 1.21, 1.68), exposure to second-hand smoke (SHS) at work (HR = 1.17, 95%CI: 1.01, 1.35), dust exposure (HR = 1.49, 95%CI: 1.06, 2.11), history of lung disease (HR = 1.44, 95%CI: 1.16, 1.77), and family history of cancer (HR = 1.28, 95%CI: 1.12, 1.48) were associated with pulmonary nodules. However, consumption of vegetables (HR = 0.82, 95%CI: 0.68, 0.99), tea (HR = 0.88, 95%CI: 0.78, 0.99) and legumes reduced the risk. Approximately 10.09% and 8.58% of pulmonary nodule incidences were attributed to tobacco smoking and low fruit intake, respectively. An estimated 6.36% and 3.88% of patients with pulmonary nodules attributable to family history of cancer and history of lung disease were detected.

CONCLUSION

The results of this study suggest that age, smoking, SHS, dietary factors, occupational exposures, history of disease and family history of cancer may affect the incidence of pulmonary nodules.

A Combination of Shape and Texture Features for Classification of Pulmonary Nodules in Lung CT Images

Classification of malignant and benign pulmonary nodules is important for further treatment plan. The present work focuses on the classification of benign and malignant pulmonary nodules using support vector machine. The pulmonary nodules are segmented using a semi-automated technique, which requires only a seed point from the end user. Several shape-based, margin-based, and texture-based features are computed to represent the pulmonary nodules. A set of relevant features is determined for the efficient representation of nodules in the feature space. The proposed classification scheme is validated on a data set of 891 nodules of Lung Image Database Consortium and Image Database Resource Initiative public database. The proposed classification scheme is evaluated for three configurations such as configuration 1 (composite rank of malignancy "1" and "2" as benign and "4" and "5" as malignant), configuration 2 (composite rank of malignancy "1","2", and "3" as benign and "4" and "5" as malignant), and configuration 3 (composite rank of malignancy "1" and "2" as benign and "3","4" and "5" as malignant). The performance of the classification is evaluated in terms of area (A z) under the receiver operating characteristic curve. The A z achieved by the proposed method for configuration-1, configuration-2, and configuration-3 are 0.9505, 0.8822, and 0.8488, respectively. The proposed method outperforms the most recent technique, which depends on the manual segmentation of pulmonary nodules by a trained radiologist.

Screening for Lung Cancer: CHEST Guideline and Expert Panel Report

BACKGROUND

Low-dose chest CT screening for lung cancer has become a standard of care in the United States in the past few years, in large part due to the results of the National Lung Screening Trial. The benefit and harms of low-dose chest CT screening differ in both frequency and magnitude. The translation of a favorable balance of benefit and harms into practice can be difficult. Here, we update the evidence base for the benefit, harms, and implementation of low radiation dose chest CT screening. We use the updated evidence base to provide recommendations where the evidence allows, and statements based on experience and expert consensus where it does not.

METHODS

Approved panelists developed key questions using the PICO (population, intervention, comparator, and outcome) format to address the benefit and harms of low-dose CT screening, as well as key areas of program implementation. A systematic literature review was conducted by using MEDLINE via PubMed, Embase, and the Cochrane Library. Reference lists from relevant retrievals were searched, and additional papers were added. The quality of the evidence was assessed for each critical or important outcome of interest using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. Important clinical questions were addressed based on the evidence developed from the systematic literature review. Graded recommendations and ungraded statements were drafted, voted on, and revised until consensus was reached.

RESULTS

The systematic literature review identified 59 studies that informed the response to the 12 PICO questions that were developed. Key clinical questions were addressed resulting in six graded recommendations and nine ungraded consensus based statements.

CONCLUSIONS

Evidence suggests that low-dose CT screening for lung cancer results in a favorable but tenuous balance of benefit and harms. The selection of screen-eligible patients, the quality of imaging and image interpretation, the management of screen-detected findings, and the effectiveness of smoking cessation interventions can affect this balance. Additional research is needed to optimize the approach to low-dose CT screening.

Multiple-level validation identifies PARK2 in the development of lung cancer and chronic obstructive pulmonary disease

An important precursor to lung cancer development is chronic obstructive pulmonary disease (COPD), independent of exposure to tobacco smoke. Both diseases are associated with increased host susceptibility, inflammation, and genomic instability. However, validation of the candidate genes and functional confirmation to test shared genetic contribution and cellular mechanisms to the development of lung cancer in patients with COPD remains underexplored. Here, we show that loss of PARK2 (encoding Parkin) increases the expression of proinflammation factors as well as nuclear NF-κB localization, suggesting a role of PARK2 loss in inflammation. Additional exploration showed that PARK2 deficiency promotes genomic instability and cell transformation. This role of PARK2 in inflammation and chromosome instability provides a potential link among Parkin, COPD and lung cancer. A further comprehensive validation of 114 informative single nucleotide polymorphism (SNP) variants of PARK2, in 2,484 cases and controls with well-defined lung cancer and COPD phenotypes, found rs577876, rs6455728 and rs9346917 (p<0.01) to be significantly associated with lung cancer development in people with COPD. Our findings support the evidence that PARK2 might have a tumor suppressor role in the development of COPD and lung cancer.

Systemic air embolism after computed tomography-guided hook wire localization: two case reports and literature review

Computed tomography (CT)-guided hook wire localization is often used to identify small nodules prior to video-assisted thoracoscopic surgery (VATS). Pneumothorax, intrapulmonary hemorrhage, and wire dislodgement are well-known complications associated with the former procedure, but systemic air embolism (SAE) is an extremely rare and potentially fatal complication. We encountered two cases of SAE; one patient showed neurologic symptoms, whereas the other did not. With the patient in the supine position, 100% oxygen was inhaled via a face mask. Subsequently, symptoms were resolved, and we performed planned surgeries on that day. Operative and postoperative courses were uneventful, and both patients were discharged without any sequelae. In this case report, we describe our experience with the two patients and review related literature.

Cell-Free DNA Quantification and Methylation Status of DCC Gene as Predictive Diagnostic Biomarkers of Lung Cancer in Patients Reported at Gulab Devi Chest Hospital, Lahore

The worldwide high mortality rate of lung cancer could be reduced significantly by its noninvasive early detection. The quantitative analysis of cell-free circulating DNA in plasma presents a potential noninvasive approach for liquid biopsy of tumor. In this study, real-time polymerase chain reaction–based approach was used to quantify free circulating DNA in plasma. The concentration of free circulating DNA was checked using human telomerase reverse transcriptase gene as marker, and amplification status of oncogene RAC-β serine/threonine protein kinase along with the DNA methylation status of tumor suppressor gene (deleted in colorectal cancer) was assessed. The concentration of free circulating DNA in patients with lung cancer (22.8 ng/mL) was found approximately 6 times above than the value detected in controls (2.8 ng/mL). Considerable variation in the AKT2 copy number was observed in patients with lung cancer and controls (P < .000). Aberrant methylation of the deleted in colorectal cancer promoter was found to be highly specific (100%), as none of the control plasma samples showed aberrant methylation. The quantification of free circulating DNA along with determination of AKT2 amplification and deleted in colorectal cancer promoter methylation status appeared promising to differentiate patients with lung cancer from healthy individuals.

Lung Cancer Risk Associated With New Solid Nodules in the National Lung Screening Trial

OBJECTIVE

As low-dose CT (LDCT) lung cancer screening moves into routine clinical practice, evaluation of nodules identified as new becomes critical. We examine the frequency and clinical outcomes of new lung nodules reported at the two postbaseline annual screening examinations (hereafter referred to as postbaseline time 1 [T1] and time 2 [T2]), compared with those detected at baseline in the National Lung Screening Trial.

MATERIALS AND METHODS

Radiologists classified nodules detected at T1 and T2 as new or preexisting on the basis of comparison with findings from prior LDCT screening examinations. Subjects were tracked for lung cancer incidence and mortality. We examined the incidence of new nodules and their associated lung cancer risk by nodule size (i.e., mean diameter).

RESULTS

A total of 25,002 subjects underwent the baseline LDCT screening examination and either a T1 or T2 LDCT screen. At both T1 and T2, 2.6% of subjects had new solid nodules. Of the new solid nodules, 53.0% were < 6 mm, 29.5% were 6 to < 10 mm, and 17.1% were ≥ 10 mm. Lung cancer risk (defined as diagnosis within 2 years of baseline) increased from 1.1% for nodules < 4 mm to 24.0% for those ≥ 20 mm. Compared with solid nodules detected at baseline, the cancer risk was higher for new solid nodules that were 4 to < 6 mm (p < 0.001) and 6 to < 8 mm (p < 0.001) but lower for new nodules ≥ 20 mm (p = 0.03). Cancers associated with new nodules had significantly poorer survival than did those associated with baseline nodules and were significantly less likely to be adenocarcinoma.

CONCLUSION

The incidence of new nodules was 2-3% annually, with the cancer risk increasing by nodule size. New nodules may convey differential lung cancer risks by size, compared with baseline nodules.

Multi-resolution classification of exhaled aerosol images to detect obstructive lung diseases in small airways

Exhaled aerosol patterns have been used to detect obstructive respiratory diseases in the upper airways. Signals from small airway diseases are weak and may not manifest themselves in the exhaled aerosol patterns. Therefore, it will be more challenging to detect abnormalities in small airways. The objective of this study is to develop a simulation-based classification model that can accurately classify small airway diseases. The model performance was evaluated in five obstructed models that are located in lung bifurcations G7-9. The exhaled aerosol images were quantified using local fractal dimensions at different sampling resolutions (n × n). The datasets were classified using both the random forest (RF) and support vector machine (SVM) algorithms. Results show that RF performs slightly and persistently better than SVM. The sampling resolution of 12 × 12 gave the optimal classification for both algorithms. Based on the lung models with predefined obstructive levels, the optimal classification accuracy is 87.0% for 5-class classification, and is 92.5% for 4-class classification by regrouping the mislabeled samples. The proposed model with multi-resolution fractal feature extraction and RF algorithm appears to be sensitive enough to accurately distinguish airway abnormalities in small airways beyond G7 with healthy bronchiole diameter <4 mm. This aerosol-based breath test is promising to develop into an alternative or supplemental tool to the low-dose CT scanning for lung cancer screening.

Small pulmonary nodules in baseline and incidence screening rounds of low-dose CT lung cancer screening

Currently, lung cancer screening by low-dose computed tomography (LDCT) is widely recommended for high-risk individuals by US guidelines, but there still is an ongoing debate concerning respective recommendations for European countries. Nevertheless, the available data regarding pulmonary nodules released by lung cancer screening studies could improve future screening guidelines, as well as the clinical practice of incidentally detected pulmonary nodules on routine CT scans. Most lung cancer screening trials present results for baseline and incidence screening rounds separately, clustering pulmonary nodules initially found at baseline screening and newly detected pulmonary nodules after baseline screening together. This approach does not appreciate possible differences among pulmonary nodules detected at baseline and firstly detected at incidence screening rounds and is heavily influenced by methodological differences of the respective screening trials. This review intends to create a basis for assessing non-calcified pulmonary nodules detected during LDCT lung cancer screening in a more clinical relevant manner. The aim is to present data of non-calcified pulmonary baseline nodules and new non-calcified pulmonary incident nodules without clustering them together, thereby also simplifying translation to the clinical practice of incidentally detected pulmonary nodules. Small pulmonary nodules newly detected at incidence screening rounds of LDCT lung cancer screening may possess a greater lung cancer probability than pulmonary baseline nodules at a smaller size, which is essential for the development of new guidelines.

Volume versus diameter assessment of small pulmonary nodules in CT lung cancer screening

Currently, lung cancer screening by low-dose chest CT is implemented in the United States for high-risk persons. A disadvantage of lung cancer screening is the large number of small-to-intermediate sized lung nodules, detected in around 50% of all participants, the large majority being benign. Accurate estimation of nodule size and growth is essential in the classification of lung nodules. Currently, manual diameter measurements are the standard for lung cancer screening programs and routine clinical care. However, European screening studies using semi-automated volume measurements have shown higher accuracy and reproducibility compared to diameter measurements. In addition to this, with the optimization of CT scan techniques and reconstruction parameters, as well as advances in segmentation software, the accuracy of nodule volume measurement can be improved even further. The positive results of previous studies on volume and diameter measurements of lung nodules suggest that manual measurements of nodule diameter may be replaced by semi-automated volume measurements in the (near) future.

Plasma miR-145, miR-20a, miR-21 and miR-223 as novel biomarkers for screening early-stage non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related mortality in the world. Late diagnosis is one of the most significant reasons for the high mortality rate of lung cancer. The identification of microRNAs (miRNAs) has opened a new field for molecular diagnosis of cancer. The purpose of the present study was to investigate whether plasma miRNAs may be used as biomarkers for early-stage NSCLC. A total of 232 participants, including 149 NSCLC patients and 83 healthy controls, were recruited between July 2012 and May 2014. We measured the levels of 10 miRNAs (miR-30d, miR-383, miR-20a, miR-145, miR-221, miR-25, miR-223, miR-21, miR-126 and miR-210) in plasma samples of 40 individuals (20 patients and 20 matched healthy controls) at the point of identification of disease, and 129 NSCLC patients and 83 healthy controls at the validation stage using reverse transcription-quantitative polymerase chain reaction. Receiver operating characteristics (ROC) curves were generated for each possible combination of the miRNAs. We observed that the expression of plasma miR-145, miR-20a, miR-21 and miR-223 was significantly increased in the early-stage NSCLC samples compared with controls. miRNAs have significant diagnostic value for early-stage NSCLC. Combined ROC analyses using these four miRNAs revealed an elevated area under the ROC curve (AUC) of 0.897, with a sensitivity and specificity of 81.8 and 90.1%, respectively. This AUC helped in distinguishing early-stage NSCLC. Furthermore, the levels of the four plasma miRNAs were significantly decreased following surgery (P<0.05). Altered expression of miR-145, miR-20a, miR-21 and miR-223 in plasma are of tumor origin, and the four miRNAs may represent potential novel non-invasive biomarkers for early-stage NSCLC.

Management of the Solitary Pulmonary Nodule

Context.—

Optimal management of the patient with a solitary pulmonary nodule entails early diagnosis and appropriate treatment for patients with malignant tumors, and minimization of unnecessary interventions and procedures for those with ultimately benign nodules. With the growing number of high-resolution imaging modalities and studies available, incidentally found solitary pulmonary nodules are an increasingly common occurrence.

Objective.—

To provide guidance to clinicians involved in the management of patients with a solitary pulmonary nodule, including aspects of risk stratification, workup, diagnosis, and management.

Data Sources.—

Data for this review were gathered from an extensive literature review on the topic.

Conclusions.—

Logical evaluation and management pathways for a patient with a solitary pulmonary nodule will allow providers to diagnose and treat individuals with early stage lung cancer and minimize morbidity from invasive procedures for patients with benign lesions.

Computed tomography-guided bronchoscopy in the diagnosis of small peripheral pulmonary lesions: A retrospective study of 240 examinations in a single academic center

BACKGROUND

Factors that affect the diagnostic yield in computed tomography (CT)-guided bronchoscopy have not yet been fully evaluated. To improve the diagnostic yield of peripheral pulmonary lesions (PPLs) by CT-guided bronchoscopy, we quantitatively analyzed factors affecting the diagnostic yield.

METHODS

The data were collected for 240 PPLs in 237 patients examined by using CT-guided bronchoscopy between October 2003 and November 2011 in our respiratory center. The association of diagnostic yield with the CT bronchus sign (CT-BS), lesion size, location, number of tissue specimens, and type of bronchoscope was retrospectively assessed.

RESULTS

The diagnostic yield of PPLs with negative CT-BS was significantly lower (2.9%) than that for PPLs with positive CT-BS (52.2%; p<0.01). Among the PPLs with positive CT-BS, the yield was significantly higher in those in the left S(3) than for lesions in other bronchial segments (83.3% vs. 50.3%; p<0.05). Lesion size was not significantly associated with diagnostic yield. The yield was significantly lower in PPLs without lung tissue specimens than in lesions with biopsy specimens (p<0.01). Moreover, a thin bronchoscope produced a higher yield in comparison with other bronchoscope types (66.0% vs. 47.6%; p<0.05). Multivariate analysis revealed that the number of biopsy specimens was an independent factor affecting diagnostic yield.

CONCLUSIONS

CT-guided bronchoscopy is valuable in the diagnosis of PPLs with positive CT-BS regardless of lesion size; however, PPLs with negative CT-BS are not good candidates for CT-guided bronchoscopy. Obtaining tissue specimens by biopsy is a critical factor in diagnosing PPLs.

Enhanced characterization of solid solitary pulmonary nodules with Bayesian analysis-based computer-aided diagnosis

The aim of this study was to prospectively assess the accuracy gain of Bayesian analysis-based computer-aided diagnosis (CAD) vs human judgment alone in characterizing solitary pulmonary nodules (SPNs) at computed tomography (CT). The study included 100 randomly selected SPNs with a definitive diagnosis. Nodule features at first and follow-up CT scans as well as clinical data were evaluated individually on a 1 to 5 points risk chart by 7 radiologists, firstly blinded then aware of Bayesian Inference Malignancy Calculator (BIMC) model predictions. Raters’ predictions were evaluated by means of receiver operating characteristic (ROC) curve analysis and decision analysis. Overall ROC area under the curve was 0.758 before and 0.803 after the disclosure of CAD predictions (P = 0.003). A net gain in diagnostic accuracy was found in 6 out of 7 readers. Mean risk class of benign nodules dropped from 2.48 to 2.29, while mean risk class of malignancies rose from 3.66 to 3.92. Awareness of CAD predictions also determined a significant drop on mean indeterminate SPNs (15 vs 23.86 SPNs) and raised the mean number of correct and confident diagnoses (mean 39.57 vs 25.71 SPNs). This study provides evidence supporting the integration of the Bayesian analysis-based BIMC model in SPN characterization.

[Diagnostic work-up of pulmonary nodules : Management of pulmonary nodules detected with low‑dose CT screening]

Pulmonary nodules are the most frequent pathological finding in low-dose computed tomography (CT) scanning for early detection of lung cancer. Early stages of lung cancer are often manifested as pulmonary nodules; however, the very commonly occurring small nodules are predominantly benign. These benign nodules are responsible for the high percentage of false positive test results in screening studies. Appropriate diagnostic algorithms are necessary to reduce false positive screening results and to improve the specificity of lung cancer screening. Such algorithms are based on some of the basic principles comprehensively described in this article. Firstly, the diameter of nodules allows a differentiation between large (>8 mm) probably malignant and small (<8 mm) probably benign nodules. Secondly, some morphological features of pulmonary nodules in CT can prove their benign nature. Thirdly, growth of small nodules is the best non-invasive predictor of malignancy and is utilized as a trigger for further diagnostic work-up. Non-invasive testing using positron emission tomography (PET) and contrast enhancement as well as invasive diagnostic tests (e.g. various procedures for cytological and histological diagnostics) are briefly described in this article. Different nodule morphology using CT (e.g. solid and semisolid nodules) is associated with different biological behavior and different algorithms for follow-up are required. Currently, no obligatory algorithm is available in German-speaking countries for the management of pulmonary nodules, which reflects the current state of knowledge. The main features of some international and American recommendations are briefly presented in this article from which conclusions for the daily clinical use are derived.

Early detection of lung cancer

Most patients with lung cancer are diagnosed when they present with symptoms, they have advanced stage disease, and curative treatment is no longer an option. An effective screening test has long been desired for early detection with the goal of reducing mortality from lung cancer. Sputum cytology, chest radiography, and computed tomography (CT) scan have been studied as potential screening tests. The National Lung Screening Trial (NLST) demonstrated a 20% reduction in mortality with low-dose CT (LDCT) screening, and guidelines now endorse annual LDCT for those at high risk. Implementation of screening is underway with the desire that the benefits be seen in clinical practice outside of a research study format. Concerns include management of false positives, cost, incidental findings, radiation exposure, and overdiagnosis. Studies continue to evaluate LDCT screening and use of biomarkers in risk assessment and diagnosis in attempt to further improve outcomes for patients with lung cancer.

CT screening for lung cancer: Frequency of enlarged adrenal glands identified in baseline and annual repeat rounds

OBJECTIVES

To determine the frequency of adrenal enlargement of participants in a CT-screening program for lung cancer and demonstrate the progression during follow-up, separately for baseline and annual repeat rounds.

MATERIALS AND METHODS

HIPAA-compliant informed consent was obtained in 4,776 participants. The adrenal gland was defined as enlarged if it measured ≥6 mm at its largest diameter. Logistic regression analyses were performed.

RESULTS

At baseline, 202 (4 %) of 4,776 participants had adrenal enlargement. Significant factors were age (OR = 1.4, 95 % CI: 1.2-1.7) and current smoker (OR = 1.8, 95 % CI: 1.3-2.4). Follow-up 7-18 months after baseline for 133 cases with adrenal enlargement <40 mm showed it decreased or was stable in 85 (64 %), and increased by <10 mm in 48 (36 %). Five (0.04 %) cases of adrenal enlargement were newly identified, none increased beyond 40 mm on follow-up. Adrenal enlargement was a significant predictor of a subsequent diagnosis of lung cancer (OR = 2.0, 95 % CI: 1.2-3.4).

CONCLUSION

Participants with adrenal enlargement <40 mm identified at baseline and on repeat screening could be reasonably assessed on subsequent annual screening. Adrenal enlargement increased with increasing pack-years of smoking. Adrenal enlargement was an independent predictor of a subsequent diagnosis of lung cancer.

KEY POINTS

• Adrenal enlargement was seen in 4 % of participants at baseline screening. • Age and currently smoking were significantly associated with adrenal enlargement. • 0.04 % of participants were newly identified with adrenal enlargement. • Annual follow-up for adrenal enlargement <40 mm was appropriate. • Adrenal enlargement was an independent predictor of a diagnosis of lung cancer.

Role of quantitative computed tomography texture analysis in the differentiation of primary lung cancer and granulomatous nodules

BACKGROUND

Texture analysis is a computer tool that enables quantification of gray-level patterns, pixel interrelationships, and spectral properties of an image. It can enhance visual methods of image analysis. Primary lung cancer and granulomatous nodules have identical CT imaging features. The purpose of this study was to assess the sensitivity and specificity of CT texture analysis in differentiating lung cancer and granulomas.

METHODS

This retrospective study evaluated 55 patients with primary lung cancer and granulomatous nodules who had contrast-enhanced (CE) and/or non-contrast-enhanced (NCE) CT within 3 months of biopsy. Textural features were extracted from 61 nodules. Mann-Whitney U tests were used to compare values for nodules. Receiver operating characteristic (ROC) curves were constructed and the area under the curve (AUC) calculated with histopathology as outcome. Combinations of features were entered as predictors in logistic regression models and optimal threshold criteria were used to estimate sensitivity and specificity.

RESULTS

The model generated by sum of squares, sum difference, and sum entropy features for NCE CT yielded 88% sensitivity and 92% specificity (AUC =0.90±0.06, P<0.0001). For nodules with fluorodeoxyglucose positron emission tomography (FDG-PET)/CT, sensitivity for detection of lung cancer was 79.2% (CI: 57.8-92.9%), specificity was 38.5% (CI: 13.9-68.4%) and accuracy was 64.8%.

CONCLUSIONS

Quantitative CT texture analysis has the potential to differentiate primary lung cancer and granulomatous lesions.

Cost-effectiveness analysis of lung cancer screening with low-dose computerised tomography of the chest in Poland

Aim of the study

To determine the cost-effectiveness of lung cancer (LC) screening with low-dose computerised tomography of the chest, as compared to an approach without screening, reimbursed today by the National Health Fund (NHF) in Poland.

Material and methods

In order to analyse the current costs of diagnostic and therapeutic procedures of a model LC patient treated today, a model group consisting of 199 consecutive patients diagnosed and treated in the Oncology Centre in Bydgoszcz, Poland from January 2007 to April 2010 was used. The number and type of performed procedures in this group was obtained from the Polish Register of Neoplasms and the NHF. Only direct medical costs were analysed. To calculate the total costs of screening, diagnostics, and treatment of the hypothetical LC patient who would have cancer diagnosed with screening CT, data from the literature and costs calculated for the model group were used. Prices of procedures were obtained from the price list of the NHF on 30 April 2010 and did not change from that time until June 2014. One-way sensitivity analysis was performed.

Results

The average cost per LC patient, diagnosed and treated without screening, is 5567.50 EUR, and median LC-specific survival is one year. In the hypothetical LC patient with cancer diagnosed by screening, the average cost is 13689.35 EUR per LC patient, with a median LC-specific survival of at least seven years. A calculated incremental cost-effectiveness ratio (ICER) is 1353.64 EUR/year of life gained.

Conclusions

Lung cancer screening with low-dose CT would be highly cost-effective in Poland.

Texture feature analysis for computer-aided diagnosis on pulmonary nodules

Differentiation of malignant and benign pulmonary nodules is of paramount clinical importance. Texture features of pulmonary nodules in CT images reflect a powerful character of the malignancy in addition to the geometry-related measures. This study first compared three well-known types of two-dimensional (2D) texture features (Haralick, Gabor, and local binary patterns or local binary pattern features) on CADx of lung nodules using the largest public database founded by Lung Image Database Consortium and Image Database Resource Initiative and then investigated extension from 2D to three-dimensional (3D) space. Quantitative comparison measures were made by the well-established support vector machine (SVM) classifier, the area under the receiver operating characteristic curves (AUC) and the p values from hypothesis t tests. While the three feature types showed about 90% differentiation rate, the Haralick features achieved the highest AUC value of 92.70% at an adequate image slice thickness, where a thinner or thicker thickness will deteriorate the performance due to excessive image noise or loss of axial details. Gain was observed when calculating 2D features on all image slices as compared to the single largest slice. The 3D extension revealed potential gain when an optimal number of directions can be found. All the observations from this systematic investigation study on the three feature types can lead to the conclusions that the Haralick feature type is a better choice, the use of the full 3D data is beneficial, and an adequate tradeoff between image thickness and noise is desired for an optimal CADx performance. These conclusions provide a guideline for further research on lung nodule differentiation using CT imaging.

Screening for lung cancer with chest computerized tomography: Is it cost efficient?

Despite lung cancer (LC) screening by low-dose computerized tomography (LDCT) gaining many proponents worldwide, for many years it was not recognized as a life-prolonging and cost-effective procedure, until recently. Prospective observational studies had not been able to prove that this screening prolongs survival, but they helped to specify the inclusion and exclusion criteria. Long-awaited results of a prospective, randomized trial finally provided the evidence that LC screening with LDCT can prolong survival of the screened population. Several cost-effectiveness analyses were performed to justify mass introduction of this screening. Results of these analyses are equivocal, although conclusions highly depend upon inclusion and exclusion criteria, methods of analysis and prices of medical procedures which differ between countries as well as the incidence of other pulmonary nodules, especially tuberculosis. Therefore, cost-effectiveness analysis should be performed separately for every country. Cost-effectiveness depends especially upon the rate of false-positive results and the rate of unnecessary diagnostic, screening and treatment procedures. To ensure high cost-effectiveness, LC screening should be performed in accordance with screening protocol, in dedicated screening centers equipped with nodule volume change analysis, or as a prospective non-randomized trial, to ensure compliance with the inclusion and exclusion criteria. To ensure high cost-effectiveness of LC screening, future research should concentrate on determination of high-risk groups and further specifying the inclusion and exclusion criteria.

Screening for lung cancer using low-dose computed tomography: concerns about the application in low-risk individuals

Low-dose computed tomography (LDCT) has been increasingly accepted as an efficient screening method for high-risk individuals to reduce lung cancer mortality. However, there remains a gap of knowledge in the practical implementation of screening on a larger scale, especially for low-risk individuals. The aim of this study is to initiate discussion through an evidence-based analysis and provide valuable suggestions on LDCT screening for lung cancer in clinical practice. Among previously published randomized controlled trials (RCTs), the National Lung Screening Trial (NLST) is the only one demonstrating positive results in a high-risk population of old age and heavy smokers. It is also shown that the potential harms include false-positive findings, radiation exposure etc., but its magnitude is uncertain. In the meantime, the current risk stratification system is inadequate, and is difficult to define selection criteria. Thus, the efficacy of LDCT in lung cancer screening needs to be confirmed in future trials, and the procedure should not be proposed to individuals without comparable risk to those in the NLST. Furthermore, there is a lack of evidence to support the expansion of LDCT screening to low-risk individuals. Therefore, recommendation of LDCT screening for these patients could be premature in clinical practice although some of them might be missed based on current definition of risk factors. Further studies and advances in risk assessment tools are urgently needed to address the concerns about lung cancer screening in order to improve the outcomes of lung cancer.

Machine learning methods for the classification of gliomas: Initial results using features extracted from MR spectroscopy

CONTEXT

With the advent of new imaging modalities, radiologists are faced with handling increasing volumes of data for diagnosis and treatment planning. The use of automated and intelligent systems is becoming essential in such a scenario. Machine learning, a branch of artificial intelligence, is increasingly being used in medical image analysis applications such as image segmentation, registration and computer-aided diagnosis and detection. Histopathological analysis is currently the gold standard for classification of brain tumors. The use of machine learning algorithms along with extraction of relevant features from magnetic resonance imaging (MRI) holds promise of replacing conventional invasive methods of tumor classification.

AIMS

The aim of the study is to classify gliomas into benign and malignant types using MRI data.

SETTINGS AND DESIGN

Retrospective data from 28 patients who were diagnosed with glioma were used for the analysis. WHO Grade II (low-grade astrocytoma) was classified as benign while Grade III (anaplastic astrocytoma) and Grade IV (glioblastoma multiforme) were classified as malignant.

METHODS AND MATERIALS

Features were extracted from MR spectroscopy. The classification was done using four machine learning algorithms: multilayer perceptrons, support vector machine, random forest and locally weighted learning.

RESULTS

Three of the four machine learning algorithms gave an area under ROC curve in excess of 0.80. Random forest gave the best performance in terms of AUC (0.911) while sensitivity was best for locally weighted learning (86.1%).

CONCLUSIONS

The performance of different machine learning algorithms in the classification of gliomas is promising. An even better performance may be expected by integrating features extracted from other MR sequences.

Imaging the solitary pulmonary nodule

The development of widespread lung cancer screening programs has the potential to dramatically increase the number of thoracic computed tomography (CT) examinations performed annually in the United States, resulting in a greater number of newly detected, indeterminate solitary pulmonary nodules (SPNs). Additional imaging studies, such as fluorodeoxyglucose F 18 (FDG)-positron emission tomography (PET), have been shown to provide valuable information in the assessment of indeterminate SPNs. Newer technologies, such as contrast-enhanced dual-energy chest CT and FDG-PET/CT, also have the potential to facilitate diagnosis of potentially malignant SPNs.

SBRT in operable early stage lung cancer patients

Since decades the gold standard for treatment of early stage non-small cell lung cancer (NSCLC) is surgical lobectomy plus mediastinal lymph node dissection. Patients in worse health status are treated with sublobar resection or radiation treatment. With development of stereotactic-body-radiotherapy (SBRT), outcome of patients treated with radiation was substantially improved. Comparison of SBRT and surgical techniques is difficult due to the lack of randomized trials. However, all available evidence in form of case control studies of population based studies show equivalence between sublobar resection and SBRT indicating that SBRT-when performed by a trained and experienced team-should be offered to all high-risk surgical patients. For patients not willing to take the risk of lobectomy and therefore refusing surgery, SBRT is an excellent treatment option.

Prevalence and significance of incidentally noted dilation of the ascending aorta on routine chest computed tomography in older patients

OBJECTIVE

The aim of this study was to determine the prevalence of incidental ascending aortic dilation and its significance over time in 55- to 80-year-olds undergoing routine computed tomographic scans.

METHODS

Chest computed tomography reports for 64,092 patients who met the inclusion criteria were used to determine the prevalence of incidental ascending aortic dilation (4-5 cm) and, when possible, aortic growth rates. A chart review was performed to identify any aortic complication or intervention.

RESULTS

The prevalence of incidental aortic dilation was 2.7% (671/24,992 patients). Of the 327 patients with aortic dilation and follow-up studies (mean, 3.4 years), only 3.7% (n = 12) demonstrated interval growth (mean of 0.9 mm/y). No patient underwent prophylactic surgery or intervention on the basis of aortic size or growth rate. One patient developed a type A dissection.

CONCLUSIONS

Current guidelines for yearly surveillance imaging of aortic dilation could be revised to increase the follow-up interval and/or improve risk stratification to better identify the small subset of patients most likely to have disease progression.

Detection of pure ground-glass nodules in the lung by low-dose multi-detector computed tomography, with use of an iterative reconstruction method: a comparison with conventional image reconstruction by the filtered back-projection method

PURPOSE

To evaluate the feasibility of the iterative reconstruction (IR) method with low-dose multi-detector computed tomography (MDCT) for lung cancer screening.

MATERIALS AND METHODS

A chest CT phantom containing simulated ground-glass nodules (GGNs) of 5 different sizes was scanned by use of 16-row and 64-row MDCT. Tube currents of 10, 20, and 30 mA were used for the low-dose CT. To assess the detectability of pure GGNs, a radiologist-performance test was conducted. Mean visual scores for simulated GGNs were compared for reconstructed images from filtered back-projection (FBP) and the IR method.

RESULTS

When 64-row MDCT was used, visual scores for simulated GGNs were significantly higher for the IR method than for the FBP method under any conditions; scores were also significantly higher for 16-row MDCT under some conditions.

CONCLUSIONS

The results of this experimental chest phantom study showed that use of the IR method improved the detectability of simulated pure GGNs.

Imaging-based screening: understanding the controversies

OBJECTIVE

The goals of this article are to provide an overview of controversial aspects of imaging-based screening and to elucidate potential risks that may offset anticipated benefits.

CONCLUSION

Current controversial topics associated with imaging-based screening include false-positive results, incidental findings, overdiagnosis, radiation risks, and costs. Alongside the benefits of screening, radiologists should be prepared to discuss these additional diagnostic consequences with providers and patients to better guide shared decision making regarding imaging-based screening.

Long-term effects of inhaled budesonide on screening-detected lung nodules

BACKGROUND

A previously carried out randomized phase IIb, placebo-controlled trial of 1 year of inhaled budesonide, which was nested in a lung cancer screening study, showed that non-solid and partially solid lung nodules detected by low-dose computed tomography (LDCT), and not immediately suspicious for lung cancer, tended to regress. Because some of these nodules may be slow-growing adenocarcinoma precursors, we evaluated long-term outcomes (after stopping the 1-year intervention) by annual LDCT.

PATIENTS AND METHODS

We analyzed the evolution of target and non-target trial nodules detected by LDCT in the budesonide and placebo arms up to 5 years after randomization. The numbers and characteristics of lung cancers diagnosed during follow-up were also analyzed.

RESULTS

The mean maximum diameter of non-solid nodules reduced significantly (from 5.03 mm at baseline to 2.61 mm after 5 years) in the budesonide arm; there was no significant size change in the placebo arm. The mean diameter of partially solid lesions also decreased significantly, but only by 0.69 mm. The size of solid nodules did not change. Neither the number of new lesions nor the number of lung cancers differed in the two arms.

CONCLUSIONS

Inhaled budesonide given for 1 year significantly decreased the size of non-solid nodules detected by screening LDCT after 5 years. This is of potential importance since some of these nodules may progress slowly to adenocarcinoma. However, further studies are required to assess clinical implications.

CLINICAL TRIAL NUMBER

NCT01540552.

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.

The Role of Neoadjuvant Therapy in Characterizing Indeterminate Lung Lesions in Patients with Resectable Colorectal Liver Metastases

BACKGROUND

Incidental pulmonary lesions are frequently found during the preoperative evaluation of patients considered for resection of colorectal liver metastases (CRLM), and their presence can confound management decisions. This study investigates the role of clinical and radiologic factors, including response to preoperative systemic chemotherapy, in determining the malignant probability of these lesions.

METHODS

Computed tomography (CT) scans of 33 patients with small (≤1 cm) lung lesions undergoing resection for CRLM after preoperative chemotherapy were reviewed. Radiological features were recorded from three sequential CT scans (baseline, postchemotherapy, and follow-up). Malignancy was diagnosed either by resection or serial imaging. Chemotherapy response comparing lung lesions and CRLM was categorized as: (1) concordant or (2) discordant. Chemotherapy response, imaging features, and other clinical factors were evaluated in multivariate analyses as predictors of malignancy.

RESULTS

Among the 86 indeterminate lung lesions identified, 23 % (20/86) were found to be metastases on follow-up. Lesions 6-10 mm were more likely to be metastases (odds ratio [OR] = 3.14, p = 0.045), as were lesions located in the lower lobes (OR = 4.50, p = 0.018). Concordant chemotherapy response was found in 13 of 86 (15 %) and was independently associated with metastatic disease (OR = 19.87, p < 0.001), with 11 of 13 (85 %) lesions determined to be metastases. In contrast, only 9 of 73 lesions (12 %) with discordant response were found to be metastases.

CONCLUSIONS

Lesion size, location, and chemotherapy response pattern were independent predictors of malignancy for patients with resectable CRLM and small indeterminate lung lesions. Utilization of preoperative chemotherapy can be a useful method of ruling out pulmonary metastases in these patients.

Serum miR-152, miR-148a, miR-148b, and miR-21 as novel biomarkers in non-small cell lung cancer screening

Lung cancer, predominantly by non-small cell lung cancer (NSCLC), is the leading cause of cancer-related deaths over the world. Late diagnosis is one of important reasons for high mortality rate in lung cancer. Current diagnostic approaches have disadvantages such as low accuracy, high cost, invasive procedure, etc. MicroRNAs were previously proposed as promising novel biomarkers in cancer screening. In this study, we evaluated the predictive power of four candidate miRNAs in NSCLC detection. Our study involved 152 NSCLC patients and 300 healthy controls. Blood samples were obtained from the total 452 subjects. After miRNA extraction from serum, the expression of miRNAs in cases and controls were quantified by qRT-PCR and normalized to the level of U6 small RNA. Statistical analyses were performed to compare miRNA levels between cases and controls. Stratified analyses were employed to compare miRNA levels in NSCLC patients with different clinical characteristics. Serum miR-148a, miR-148b, and miR-152 were significantly downregulated in NSCLC patients. However, overexpression of serum miR-21 was observed in NSCLC patients. The combination of four candidate miRNAs exhibited the highest predictive accuracy in NSCLC screening compared with individual miRNAs (AUC = 0.97). Low level of miRNA-148/152 members may associate with advanced stage, large tumor size, malignant cell differentiation, and metastasis. High expression of miR-21 was possibly correlated with large size tumor and advanced cancer stage. Our results showed the dysregulation of miR-148/152 family and miR-21 in NSCLC patients. Hence, the four candidate miRNAs have great potential to serve as promising novel biomarkers in NSCLC screening. Further large-scale studies are needed to validate our results.

Developing and Testing of an Oral Health Screening Tool for Midwives to Assess Pregnant Woman

Maternal oral health is important, and midwives are encouraged to screen women for dental problems. We aimed to develop and test a midwifery oral health screening tool. A three-item tool was tested as part of a trial involving 300 women in Southwestern Sydney. A two-item combination showed better sensitivity (98%) and had a positive predictive value of 88%. Specificity was 40%, and negative predictive value was 80%. A two-item screening tool has been identified that is sensitive to identifying dental problems and facilitating referrals. Further validation using a larger sample is required to reassess the tool's specificity.