Screening for lung cancer. Another look; a different view

Asian Perspective on Lung Cancer Screening

Lung cancer is the leading cause of cancer-related mortality in Japan and worldwide. Early detection of lung cancer is an important strategy for decreasing mortality. Advances in diagnostic imaging have made it possible to detect lung cancer at an early stage in medical practice. Conversely, screening of asymptomatic healthy populations is recommended only when the evidence shows the benefits of regular intervention. Due to a variety of evidence and racial differences, screening methods vary from country to country. This article focused on the perspective of lung cancer screening in Japan.

Artificial Intelligence for Cardiothoracic Imaging: Overview of Current and Emerging Applications

Artificial intelligence algorithms can learn by assimilating information from large datasets in order to decipher complex associations, identify previously undiscovered pathophysiological states, and construct prediction models. There has been tremendous interest and increased incorporation of artificial intelligence into various industries, including healthcare. As a result, there has been an exponential rise in the number of research articles and industry participants producing models intended for a variety of applications in medical imaging, which can be challenging to navigate for radiologists. In thoracic imaging, multiple applications are being evaluated for chest radiography and computed tomography and include applications for lung nodule evaluation and cancer imaging, quantifying diffuse lung disorders, and cardiac imaging, to name a few. This review aims to provide an overview of current clinical AI models, focusing on the most common clinical applications of AI in cardiothoracic imaging.

Artificial Intelligence in Lung Cancer Imaging: Unfolding the Future

Lung cancer is one of the malignancies with higher morbidity and mortality. Imaging plays an essential role in each phase of lung cancer management, from detection to assessment of response to treatment. The development of imaging-based artificial intelligence (AI) models has the potential to play a key role in early detection and customized treatment planning. Computer-aided detection of lung nodules in screening programs has revolutionized the early detection of the disease. Moreover, the possibility to use AI approaches to identify patients at risk of developing lung cancer during their life can help a more targeted screening program. The combination of imaging features and clinical and laboratory data through AI models is giving promising results in the prediction of patients’ outcomes, response to specific therapies, and risk for toxic reaction development. In this review, we provide an overview of the main imaging AI-based tools in lung cancer imaging, including automated lesion detection, characterization, segmentation, prediction of outcome, and treatment response to provide radiologists and clinicians with the foundation for these applications in a clinical scenario.

The 100 most cited articles on lung cancer screening: a bibliometric analysis

Background

The number of citations of an article reflects its impact on the scientific community. The aim of this study was to identify and characterize the 100 most cited articles on lung cancer screening.

Methods

The 100 most cited articles on lung cancer screening published in all scientific journals were identified using the Web of Science database. Relevant data, including the number of citations, publication year, publishing journal and impact factor (IF), authorship and country of origin, article type and study design, screening modality, and main topic, were collected and analyzed.

Results

The 100 most cited articles were all English and published between 1973 and 2017, with 81 published after 2000. The mean number of citations was 292.90 (range 100–3,910). Sixty articles originated from the United States. These articles were published in 32 journals; there was a statistically significant positive correlation between journal IF and the number of citations (r=0.238, P=0.018). Seventy-nine articles were original research of which 37.9% were about results from randomized controlled trials (RCTs). The most common screening modalities in these articles were low-dose computed tomography (LDCT) (n=78), followed by chest X-ray radiography (CXR) and sputum cytology (n=11). The most common topic in these articles was screening test effectiveness.

Conclusions

Our study presents a detailed list and analysis of the 100 most cited articles published about lung cancer screening which provides insight into the historical developments and key contributions in this field.

Determining the perception of a lung cancer screening programme among high-risk patients in a tertiary referral centre, Kuala Lumpur

Background:

Lung cancer is the second most common cause of cancer-related death and the third most common cancer in Malaysia. The rising prevalence of lung cancer suggests the need to consider disease screening for early detection, especially in the high-risk population, as it offers the best chance of cure.

Objectives:

The study aims to determine the willingness of high-risk respondents to participate in a lung cancer screening programme if made available to them, and to determine their attitude towards lung cancer screening and explore factors that might affect participation in a screening programme.

Method:

This is a cross-sectional, descriptive study over 6 months conducted in adult patients attending medical clinics in Universiti Kebangsaan Malaysia Medical Centre (UKMMC) using face-to-face administered questionnaires.

Results:

In total 180 respondents were analysed. There were 177 (98.3%) males. Mean age was 59.8 ± 9.1 years. Of the respondents, 138 (76.7%) had poor knowledge about cancer screening. Former smokers comprised 119 (66.1%) of the participants, and 61 (33.9%) were current smokers. In total, 141 (78.3%) respondents indicated willingness to participate in a lung cancer screening programme. Out of this group, 68 (48.2%) respondents were unwilling to pay for the procedure. Only 18 (12.8%) were unwilling to undergo lung cancer treatment if detected early.

Conclusions:

Awareness about general cancer screening is low. Our study showed that when informed of their high-risk status, respondents were willing to participate in lung cancer screening. There should be more health programmes to promote and raise awareness about lung cancer.

Measuring the Effects of Education in Detecting Lung Cancer on Chest Radiographs: Utilization of a New Assessment Tool

This study was designed to evaluate the effect of group and individualized educational lectures to accurately interpret chest radiographs of lung cancer patients and to introduce a new educational tool in evaluating skills for reading chest radiographs. Utilizing "hotspot" technology will be instrumental in measuring the effect of education in interpreting chest radiographs. There were 48 participants in the study. Chest radiographs of 100 lung cancer patients and 11 healthy patients taken at various time points were used for evaluation. Using "hotspot" technology, lesions on each radiograph were outlined. Values were taken at baseline, after which the group received lectures. Several days later, they underwent exam 2. Exam 3 was conducted after individualized lectures. A final exam was taken after the participants underwent individualized training within 2 months. Scores significantly improved after the individual lessons (p < 0.001). This improvement in performance decreased in the final examination. Statistically significant differences were observed between exam 2 vs. exam 3 and exam 3 vs. the final exam (p < 0.001, p < 0.001). Participants demonstrated more improvement in detecting lesions in abnormal chest radiographs than in identifying normal ones. Although there was significant improvement in detecting abnormal radiographs by the end of the study (p < 0.001), no improvement was observed in detecting normal ones. We measured lung cancer detection rate using a new "hotspot" detection tool for chest radiographs. With the proposed scoring system, this tool could be objectively used in evaluating the educational effects.

Clarification of the resection line non-intubated segmentectomy using indocyanine green

A reflection on the measure of fluorescence specificity of indocyanine green (ICG) in non-intubated pulmonary segmentectomy.

Incorporating automatically learned pulmonary nodule attributes into a convolutional neural network to improve accuracy of benign-malignant nodule classification

Existing deep-learning-based pulmonary nodule classification models usually use images and benign-malignant labels as inputs for training. Image attributes of the nodules, as human-nameable high-level semantic labels, are rarely used to build a convolutional neural network (CNN). In this paper, a new method is proposed to combine the advantages of two classifications, which are pulmonary nodule benign-malignant classification and pulmonary nodule image attributes classification, into a deep learning network to improve the accuracy of pulmonary nodule classification. For this purpose, a unique 3D CNN is built to learn image attribute and benign-malignant classification simultaneously. A novel loss function is designed to balance the influence of two different kinds of classifications. The CNN is trained by a publicly available lung image database consortium (LIDC) dataset and is tested by a cross-validation method to predict the risk of a pulmonary nodule being malignant. This proposed method generates the accuracy of 91.47%, which is better than many existing models. Experimental findings show that if the CNN is built properly, the nodule attributes classification and benign-malignant classification can benefit from each other. By using nodule attribute learning as a control factor in a deep learning scheme, the accuracy of pulmonary nodule classification can be significantly improved by using a deep learning scheme.

A Resected Case of Primary Malignant Melanoma of the Esophagus—Early Detection of Recurrence by FDG-PET/CT

Primary malignant melanoma of the esophagus (PMME) is a rare, aggressive, therapy-resistant malignant tumor arising from esophageal mucosal melanocytes. It has been reported that fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has a clinical impact on PMME diagnosis; however, it remains unclear whether postoperative surveillance using FDG-PET/CT is useful for PMME patients. In this case study, FDG-PET/CT detected the recurrent tumors in their early stage after a curative resection of PMME. We report on a case of a 67-year-old Japanese male admitted to our hospital for the evaluation of polypoid tumors of the esophagogastric junction, which were diagnosed as PMME. He was treated with a curative resection by esophagectomy and 6 cycles of adjuvant chemotherapy of DAV (dacarbazine, nimustine, and vincristine). However, the PMME recurred 26 months after the surgery when surveillance FDG-PET/CT detected the recurrent tumors in their early stage. FDG-PET/CT may be useful to detect recurrence in the postoperative surveillance phase for PMME patients.

Factors Affecting the Interval from Diagnosis to Treatment in Patients with Lung Cancer

Aims and Background

We aimed to investigate the factors affecting the interval from the beginning of the symptoms until diagnosis and treatment in patients with lung cancer.

Methods

Records of 119 lung cancer patients diagnosed in our pulmonary diseases clinic between 2004 and 2006 were evaluated retrospectively. Demographic data, histopathological tumor type, TNM stage, ECOG performance status, presence of endobronchial lesions, and radiological localization of the tumor were determined. Intervals from the first symptom to contacting a doctor, to diagnosis and to treatment were calculated. The interval from first admission to a clinic and referral to a chest physician was also calculated.

Results

Of 119 patients, 74% were diagnosed as non-small cell and 26% were as small cell lung cancer. Forty-eight percent of the patients were at stage 3B and 36% were at stage 4. ECOG performance status was 0 in 6%, 1 in 52%, 2 in 36%, 3 in 3%, and 4 in 2%. Endobronchial lesions were observed in 50% of the patients, and the lesions had a central radiological localization in 59%. Fifty-four percent of the patients presented to a chest physician first. Patients who first presented to an internal medicine clinic were referred to our pulmonary disease clinic significantly later than those who presented to other clinics (P = 0.005). The median period from the beginning of the symptoms until contacting a doctor was 35 days (range, 1-387), until diagnosis was 49 days (range, 12-396), and until beginning the treatment was 57 (range, 9-397) days. The presence of endobronchial lesions, radiological localization, TNM stage and ECOG performance status were not found to be related to the intervals from the first symptom to presentation to a doctor, to diagnosis or to the beginning of the treatment.

Conclusions

Lung cancer patients consult a doctor after a relatively long symptomatic period. Patient delays may be shortened by increasing the awareness of patients about lung cancer symptoms. Diagnostic procedures should be performed more rapidly to shorten doctor delays.

Long-Term Follow-up Results of the DANTE Trial, a Randomized Study of Lung Cancer Screening with Spiral Computed Tomography

RATIONALE

Screening for lung cancer with low-dose spiral computed tomography (LDCT) has been shown to reduce lung cancer mortality by 20% compared with screening with chest X-ray (CXR) in the National Lung Screening Trial, but uncertainty remains concerning the efficacy of LDCT screening in a community setting.

OBJECTIVES

To explore the effect of LDCT screening on lung cancer mortality compared with no screening. Secondary endpoints included incidence, stage, and resectability rates.

METHODS

Male smokers of 20+ pack-years, aged 60 to 74 years, underwent a baseline CXR and sputum cytology examination and received five screening rounds with LDCT or a yearly clinical review only in a randomized fashion.

MEASUREMENTS AND MAIN RESULTS

A total of 1,264 subjects were enrolled in the LDCT arm and 1,186 in the control arm. Their median age was 64.0 years (interquartile range, 5), and median smoking exposure was 45.0 pack-years. The median follow-up was 8.35 years. One hundred four patients (8.23%) were diagnosed with lung cancer in the screening arm (66 by CT), 47 of whom (3.71%) had stage I disease; 72 control patients (6.07%) were diagnosed with lung cancer, with 16 (1.35%) being stage I cases. Lung cancer mortality was 543 per 100,000 person-years (95% confidence interval, 413-700) in the LDCT arm versus 544 per 100,000 person-years (95% CI, 410-709) in the control arm (hazard ratio, 0.993; 95% confidence interval, 0.688-1.433).

CONCLUSIONS

Because of its limited statistical power, the results of the DANTE (Detection And screening of early lung cancer with Novel imaging TEchnology) trial do not allow us to make a definitive statement about the efficacy of LDCT screening. However, they underline the importance of obtaining additional data from randomized trials with intervention-free reference arms before the implementation of population screening.

Validity of the European short list of respiratory diseases: a 40-year autopsy study

The predictors of autopsy and the accuracy of European short list (E) codes of respiratory diseases lack recent knowledge. A 10% random sample (n=6811) of inhabitants of Bergen, Norway, aged 20-70 years, was invited to participate in a survey in 1965-1971 (participation rate 83%). By December 31, 2005, 4387 (64%) participants had died and 1163 (27% of the deceased) had been given an autopsy. Causes of death were tuberculosis (E02, 0.2%), lung malignancy (E15, 3.5%), influenza (E38, 0.2%), pneumonia (E39, 6.5%) and chronic lower respiratory diseases (E40, 3.2%). Male sex, early deaths in the surveillance period and E15 were positive predictors of an autopsy examination, whereas old age and E39 were strong negative predictors. Among those referred for a post mortem examination, the cause of death was verified as tuberculosis in 0.3%, lung cancer in 8.1%, acute pneumonia in 2.0% and chronic obstructive lung diseases in 4.9%. Cohen's kappa coefficients (E codes versus autopsy) were 0.91 (95% CI 0.86-0.96) for E15, 0.37 (95% CI 0.20-0.54) for E39 and 0.65 (95% CI 0.54-0.76) for E40. These findings matter when deaths from respiratory diseases are used as end-points in epidemiological association studies and clinical trials.

[Preliminary experiences with low-dose computed tomography for lung cancer screening in Hungary]

INTRODUCTION

Lung cancer has the highest mortality rate of all types of cancers both in developed countries and Hungary.

AIM

To obtain experience and facilitate the application of low-dose computed tomography-based lung cancer screening as a targeted public health screening procedure.

METHOD

Volunteers without thoracic complaints above the age of 40 years (n = 963) were screened for lung cancer using digital chest radiography and low-dose computed tomography.

RESULTS

Two lung cancers were found among the participants screened with digital chest radiography (0.2%). After informed consent, 173 individuals with normal chest radiography findings (n = 943) took the opportunity to voluntarily participate in low-dose computed tomography screening for lung cancer. After 3 or 12 months, 65 individuals had follow up control examinations based on the size and characteristics of the detected lesions. Among them, one participant was found to have lung cancer using low-dose computed tomography.

CONCLUSIONS

These results indicate that low-dose computed tomography-based lung cancer screening as a public health screening procedure can enhance the success of screening with 50% (from 0.2% to 0.3%). The cost-benefit ratio can be raised if chest radiography is performed prior to the low-dose computed tomography examination.

Chest X-ray screening for lung cancer: overdiagnosis, endpoints, and randomized population trials

Publication of the National Lung Screening Trial (NLST) generated excitement by concluding that CT screening reduces lung cancer mortality when compared to chest X-ray (CXR) screening. In contrast, CXR screening has long been considered to be ineffective. This is because randomized population trials (RPTs) have failed to demonstrate significant mortality reductions in populations randomized to CXR screening. While these studies demonstrate that CXR screening is associated with significant survival advantages, these advantages have been widely interpreted as spurious, due to the inference that CXR screening leads to substantial lung cancer overdiagnosis. Indeed, the reality of the overdiagnosis hypothesis is the only alternative to the conclusion that CXR screening was effective in these trials and that survival more accurately reflected the benefit of CXR screening than mortality. Mortality comparisons would be biased if randomization fails to create comparison groups with an equal probability of mortality from the target cancer. The objective of this manuscript is to review existing RPTs on CXR screening for lung cancer, and to analyze which endpoint most accurately reflects screening efficacy. We conclude that the evidence supports that CXR screening is superior to no screening, and the magnitude of overdiagnosis is minimal in the context of CXR screening.

[What tools should be used for follow-up post occupational exposure? What should be the frequency?]

As long as the value of screening for cancers related to asbestos is not proven in the population at risk, the medical benefits of follow-up post-professional exposure remain uncertain and the only justification is to answer the questions of anxious retired workers concerning the consequences of their past-exposure and to provide compensation for any abnormalities that are demonstrated. In this country, to answer the questions posed in the title of this contribution in the case of pathologies related to asbestos, it is necessary, after verifying the fact and the level of exposure, to identify the pleural or pulmonary fibrosis and, above all, the pleural plaques, which constitute the essential lesions currently screened for. Thoracic CT scanning without contrast is the examination of choice to achieve this objective. There are, however, two significant problems. On one hand there is a high incidence of pulmonary micronodules, the necessary surveillance of which requires subsequent scans, leading to increased irradiation and anxiety. On the other hand the diagnostic uncertainty concerning discrete lesions is a source of confusion for the persons followed-up. There are, at present, neither scientific criteria to determine the optimum frequency of examination nor any arguments for replacing the pragmatic proposals of the consensus conference of 1999. It is important, therefore, to provide a medical assessment appropriate to the symptoms and anxiety expressed by a person previously exposed to asbestos. Overall it is necessary to question the benefit to the exposed person, in terms of quality of life, of a regular search for lesions that would usually be asymptomatic if not identified. Would it not be more judicious and more equitable to compensate persons whose past-exposure is sufficient to increase significantly their risk of cancer independently of the presence of benign abnormalities.

A population-based cohort study of chest x-ray screening in smokers: lung cancer detection findings and follow-up

BACKGROUND

Case-control studies of mass screening for lung cancer (LC) by chest x-rays (CXR) performed in the 1990s in scarcely defined Japanese target populations indicated significant mortality reductions, but these results are yet to be confirmed in western countries. To ascertain whether CXR screening decreases LC mortality at community level, we studied a clearly defined population-based cohort of smokers invited to screening. We present here the LC detection results and the 10-year survival rates.

METHODS

The cohort of all smokers of > 10 pack-years resident in 50 communities of Varese, screening-eligible (n = 5,815), in July 1997 was invited to nonrandomized CXR screening. Self-selected participants (21% of cohort) underwent screening in addition to usual care; nonparticipants received usual care. The cohort was followed-up until December 2010. Kaplan-Meier LC-specific survival was estimated in participants, in nonparticipants, in the whole cohort, and in an uninvited, unscreened population (control group).

RESULTS

Over the initial 9.5 years of study, 67 LCs were diagnosed in screening participants (51% were screen-detected) and 178 in nonparticipants. The rates of stage I LC, resectability and 5-year survival were nearly twice as high in participants (32% stage I; 48% resected; 30.5% 5-year survival) as in nonparticipants (17% stage I; 27% resected; 13.5% 5-year survival). There were no bronchioloalveolar carcinomas among screen-detected cancers, and median volume doubling time of incidence screen-detected LCs was 80 days (range, 44-318), suggesting that screening overdiagnosis was minimal. The 10-year LC-specific survival was greater in screening participants than in nonparticipants (log-rank, p = 0.005), and greater in the whole cohort invited to screening than in the control group (log-rank, p = 0.001). This favourable long-term effect was independently related to CXR screening exposure.

CONCLUSION

In the setting of CXR screening offered to a population-based cohort of smokers, screening participants who were diagnosed with LC had more frequently early-stage resectable disease and significantly enhanced long-term LC survival. These results translated into enhanced 10-year LC survival, independently related to CXR screening exposure, in the entire population-based cohort. Whether increased long-term LC-specific survival in the cohort corresponds to mortality reduction remains to be evaluated.

TRIAL REGISTRATION NUMBER

ISRCTN90639073.

Exploring the uncertainties of early detection results: model-based interpretation of mayo lung project

BACKGROUND

The Mayo Lung Project (MLP), a randomized controlled clinical trial of lung cancer screening conducted between 1971 and 1986 among male smokers aged 45 or above, demonstrated an increase in lung cancer survival since the time of diagnosis, but no reduction in lung cancer mortality. Whether this result necessarily indicates a lack of mortality benefit for screening remains controversial. A number of hypotheses have been proposed to explain the observed outcome, including over-diagnosis, screening sensitivity, and population heterogeneity (initial difference in lung cancer risks between the two trial arms). This study is intended to provide model-based testing for some of these important arguments.

METHOD

Using a micro-simulation model, the MISCAN-lung model, we explore the possible influence of screening sensitivity, systematic error, over-diagnosis and population heterogeneity.

RESULTS

Calibrating screening sensitivity, systematic error, or over-diagnosis does not noticeably improve the fit of the model, whereas calibrating population heterogeneity helps the model predict lung cancer incidence better.

CONCLUSIONS

Our conclusion is that the hypothesized imperfection in screening sensitivity, systematic error, and over-diagnosis do not in themselves explain the observed trial results. Model fit improvement achieved by accounting for population heterogeneity suggests a higher risk of cancer incidence in the intervention group as compared with the control group.

Lung cancer screening--are we there yet?

BACKGROUND

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

LITERATURE SEARCH

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

CONCLUSIONS

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

An up to date look at lung cancer screening

Lung cancer is the leading cause of cancer-related death worldwide. At the time of initial presentation, most patients are at an advance stage of disease and have a poor associated prognosis. Those diagnosed and treated at earlier stages have a significantly better outcome with 5-year survival for stage I disease approaching 75%. Ideally a screening strategy for lung cancer would detect disease at an earlier stage and allow for potential surgical cure. The purpose of this review is to examine past and current evidence as it relates to lung cancer screening.

Lung cancer screening and its efficacy

The efficacy of lung cancer screening should not be evaluated by the survival rate of lung cancer patients but by lung cancer mortality in a certain population because the survival rate can be greatly affected by several types of bias. Randomized controlled trials that were conducted during the 1970s and 1980s in Europe and the United States failed to prove the efficacy of lung cancer screening in decreasing the mortality rate; but recently the results of case-control studies in Japan have revealed that undergoing currently available screening decreases the risk of lung cancer deaths by 30%-60%. A system is now being created in Japan whereby the guidelines regarding cancer screening will continue to be updated. The preliminary reports concerning lung cancer screening using thoracic computed tomography revealed that not only the detection rate of lung cancer but also the survival rate of detected lung cancer patients were surprisingly high. However, the presence of some potential bias in these studies cannot be ignored; therefore, it is still unknown whether there is actual efficacy. Several randomized controlled trials are presently in progress overseas, but the interim results were not favorable. A randomized controlled trial should therefore immediately be started in Japan as well.

Lung cancer screening

Lung cancer is the leading cause of cancer-related death worldwide. Most patients present symptomatically when the disease is often at an advanced stage and prognosis is poor. In contrast, outcomes are significantly better in patients diagnosed at earlier stages, with a 5-year survival for stage I approaching 75%. Screening for lung cancer may detect potentially fatal cases earlier in their disease course, at a stage when a curative surgical intervention is feasible. The objective of this review is to examine the current evidence for lung cancer screening and the clinical effectiveness of screening for lung cancer by using computed tomography.

CEBPG regulates ERCC5/XPG expression in human bronchial epithelial cells and this regulation is modified by E2F1/YY1 interactions

Marked inter-individual variation in lung cancer risk cannot be accounted for solely by cigarette smoke and other environmental exposures. Evidence suggests that variation in bronchial epithelial cell expression of key DNA repair genes plays a role. Variation in these genes correlates with variation in expression of CEBPG and E2F1 transcription factors. Here, we investigated the mechanistic basis for correlation of the DNA repair gene ERCC5 (previously known as XPG) with CEBPG and E2F1. CEBPG expression vector transfected into H23 or H460 cell lines up-regulated endogenous ERCC5 and also luciferase from a reporter construct containing 589 bp of ERCC5 5' regulatory region. A recognition site for CEBPG and a region containing sites for YY1 on the sense strand and E2F1 on the anti-sense strand participated in CEBPG up-regulation of ERCC5. CEBPG, E2F1 and YY1 binding to their respective sites were confirmed by electrophoretic mobility shift assay. Thus, we conclude that CEBPG regulates ERCC5 expression and this regulation is modified by E2F1/YY1 interactions. Several polymorphisms have been identified in these regions and, based on the data presented here, it is reasonable to hypothesize that they may contribute to risk for bronchogenic carcinoma.

[Screening for early detection of lung cancer: conflict between clinical and public health viewpoints]

In Hungary, lung cancer, gradually increasing among women, is the leading cause of cancer mortality. The screening, using chest x-ray and sputum cytology as screening tool, does not reduce the mortality from lung cancer, therefore, screening for lung cancer is not recommended. The low-dose spiral CT is a sensitive and promising method, however, its specificity is far from being ideal. The results of the on-going RCTs are expected in a few years time, and so far it is not applicable for routine screening. In this country, the one-third of lung cancer cases are detected by the routine chest x-ray for tuberculosis, obligatory by law, and most of the detected cases are still resectable, but this does not have any influence on the mortality. According to our view, the detection of the lung cancer, particularly in those at high risk, is a by-product of periodic chest x-ray aiming at early detection of tuberculosis, however, mass screening for lung cancer as public health measure is not recommended. For the time being, the implementation of tobacco control measures is the only way to reduce the risk of lung cancer in the long run.

Lung metastases detection in CT images using 3D template matching

The aim of this study is to demonstrate a novel, fully automatic computer detection method applicable to metastatic tumors to the lung with a diameter of 4-20 mm in high-risk patients using typical computed tomography (CT) scans of the chest. Three-dimensional (3D) spherical tumor appearance models (templates) of various sizes were created to match representative CT imaging parameters and to incorporate partial volume effects. Taking into account the variability in the location of CT sampling planes cut through the spherical models, three offsetting template models were created for each appearance model size. Lung volumes were automatically extracted from computed tomography images and the correlation coefficients between the subregions around each voxel in the lung volume and the set of appearance models were calculated using a fast frequency domain algorithm. To determine optimal parameters for the templates, simulated tumors of varying sizes and eccentricities were generated and superposed onto a representative human chest image dataset. The method was applied to real image sets from 12 patients with known metastatic disease to the lung. A total of 752 slices and 47 identifiable tumors were studied. Spherical templates of three sizes (6, 8, and 10 mm in diameter) were used on the patient image sets; all 47 true tumors were detected with the inclusion of only 21 false positives. This study demonstrates that an automatic and straightforward 3D template-matching method, without any complex training or postprocessing, can be used to detect small lung metastases quickly and reliably in the clinical setting.

Profiling tumor-associated antibodies for early detection of non-small cell lung cancer

BACKGROUND

A blood test for non-small cell lung cancer (NSCLC) may be a valuable tool for use in a comprehensive lung cancer screening strategy. Here we report the potential of autoantibody profiling to detect early-stage and occult NSCLC.

METHODS

T7-phage NSCLC cDNA libraries were screened with patient plasma to identify phage-expressed proteins recognized by tumor-associated antibodies. Two hundred twelve immunogenic phage-expressed proteins, identified from 4000 clones, were statistically ranked for their individual reactivity with 23 stage I cancer patient and 23 risk-matched control samples. All 46 samples were used as a training set to define a combination of markers that were best able to distinguish patient from control samples; this set of classifiers was then examined using leave-one-out cross-validation. Markers were then used to predict probability of disease in 102 samples from the Mayo Clinic CT Screening Trial (six prevalence cancer samples, 40 drawn 1 to 5 years before diagnosis, and 56 risk-matched controls).

RESULTS

Measurements of the five most predictive antibody markers in 46 cases and controls were combined in a logistic regression model that yielded area under the receiver operating characteristics curve of 0.99; leave-one-out validation achieved 91.3% sensitivity and 91.3% specificity. In testing this marker set with samples from the Mayo Clinic Lung Screening Trial, we correctly predicted six of six prevalence cancers, 32 of 40 cancers from samples drawn 1 to 5 years before radiographic detection on incidence screening, and 49 of 56 risk-matched controls.

CONCLUSIONS

Antibody profiling may be a useful tool for early detection of NSCLC.

Extended lung cancer incidence follow-up in the Mayo Lung Project and overdiagnosis

BACKGROUND

A troubling aspect of cancer screening is the potential for overdiagnosis, i.e., detection of disease that, in the absence of screening, would never have been diagnosed. Overdiagnosis is of particular concern in lung cancer screening because newer screening modalities can identify small nodules of unknown clinical significance. Previously published analyses of data from the Mayo Lung Project, a large randomized controlled trial conducted among 9211 male cigarette smokers in the 1970s and early 1980s indicated that overdiagnosis might exist in lung cancer screening. At the end of follow-up (July 1, 1983), no difference in lung cancer mortality was observed, but an excess of 46 cases in the intervention arm suggested overdiagnosis. Because that excess could instead have resulted from short follow-up time, we investigated this possibility by conducting long-term lung cancer incidence follow-up.

METHODS

We investigated the lung cancer status through 1999 of the 7118 participants in the Mayo Lung Project who were alive and without diagnosed lung cancer in 1983 by use of medical records, surveys mailed to participants or next-of-kin, and state death certificates.

RESULTS

Information was available for 6101 participants, including 811 with inconclusive lung cancer status. From November 1971 through December 31, 1999, 585 participants in the intervention arm and 500 in the usual-care arm were diagnosed with lung cancer.

CONCLUSIONS

The persistence of excess cases in the intervention arm after 16 additional years of follow-up provides continued support for overdiagnosis in lung cancer screening.

Diagnóstico precoce do câncer de pulmão: o grande desafio. Variáveis epidemiológicas e clínicas, estadiamento e tratamento

OBJETIVO: Avaliar casos confirmados de câncer de pulmão, revisando suas variáveis epidemiológicas, clínicas, estadiamento e tratamento. MÉTODOS: Foram estudados 263 casos provenientes do Hospital de Clínicas da Universidade Federal do Paraná e do Hospital Erasto Gaertner, instituições responsáveis por parcela significativa do atendimento a pacientes na cidade de Curitiba (PR). Realizou-se um estudo retrospectivo através de preenchimento de questionário e os dados obtidos foram analisados de forma descritiva, utilizando-se o software EPI-INFO. RESULTADOS: Houve predomínio de pacientes do sexo masculino (76%), sendo que a maioria dos pacientes era fumante ou ex-fumante por ocasião do diagnóstico (90%). Não havia referência a doença pulmonar prévia em 87% dos casos. Tosse (142 casos) e dor torácica (92 casos) foram os sintomas iniciais mais freqüentes. O câncer de pulmão tipo não pequenas células foi encontrado em 87% dos pacientes e o tipo histológico mais freqüente foi o carcinoma espinocelular, representando 49% dos casos. O tabagismo foi considerado o fator predisponente mais importante. CONCLUSÃO: As características evolutivas do câncer de pulmão, como a inespecificidade dos sintomas iniciais e o tempo e evolução do tumor, somadas à ausência de programas de rastreamento efetivos, constituem os principais fatores que contribuem para a não detecção da neoplasia pulmonar de forma precoce, o que torna difícil o tratamento e dificulta o aumento da sobrevida.

Update in screening of lung cancer

In the USA, lung cancer is the leading cause of cancer death. Earlier studies of CXR and sputum cytology screening conducted in the 1970s showed no mortality benefit. Accordingly, mass screening for lung cancer was abandoned and is not currently recommended. Recently, interest in lung cancer screening has been revived due to various reports showing an advantage of low-dose CT over CXR in detecting smaller size tumours and at an earlier stage. Although these reports generated much enthusiasm for screening among clinicians and the general public, the effectiveness of low-dose CT in reducing lung cancer-specific mortality rates has not been demonstrated. Large-scale randomized controlled trials are currently in progress to determine the efficacy of CXR and low-dose CT screening. This review highlights the advantages and limitations of current modalities for lung cancer screening. The cases for and against screening with currently available modalities are examined. Additional new screening modalities are also discussed.

Delays in the Diagnosis and Treatment of Lung Cancer

STUDY OBJECTIVES

This study was undertaken to measure delays of diagnosis and to assess the causes for those delays in patients with lung cancer. In addition, the relation of delay times and survival was analyzed.

DESIGN

A retrospective study based on patient records. Dates for symptoms, visits to doctors, investigations, treatment, and death were recorded.

SETTING

Patients who were found to have lung cancer at Turku University Hospital, Finland, during 2001.

PATIENTS

Records of 132 patients were reexamined.

RESULTS

The median delay in patient presentation from first symptoms to first appointment with a general practitioner (GP) was 14 days. The median delay by the GP before writing a referral was 16 days, the median referral delay was 8 days, the median delay from the first visit to a specialist until the diagnosis was 15 days, and the median treatment delay was also 15 days. Thirty percent of patients received treatment within 1 month from the first hospital visit, and 61% received treatment within 2 months. The median symptom-to-treatment delay was almost 4 months. The delay in seeing a specialist was shorter in patients with advanced cancer and small cell lung cancer. About half of our patients fulfilled the criteria of the British Thoracic Society recommendations. A longer specialist treatment delay seemed to correlate with better survival in advanced disease, but it was not an independent significant factor for survival.

CONCLUSIONS

Several reasons for long delays were found, but on many occasions patients underwent numerous consecutive procedures before a diagnosis of cancer was confirmed. Shortening the diagnostic and treatment delay times might be possible with little extra cost by a multidisciplinary team approach and by rapid access to carefully planned investigations, but decreasing the patient delay might be more difficult. This study shows that long specialist treatment delays are not correlated with worse prognosis in patients with advanced disease. In patients with more limited disease, the delay time may be more critical, and if curative treatment is the goal, the diagnostic process should proceed without needless delay to avoid a situation in which curable disease becomes incurable.

Evaluation of automated lung nodule detection on low-dose computed tomography scans from a lung cancer screening program(1)

RATIONALE AND OBJECTIVES

The purpose of this study was to evaluate the performance of a fully automated lung nodule detection method in a large database of low-dose computed tomography (CT) scans from a lung cancer screening program. Because nodules demonstrate a spectrum of radiologic appearances, the performance of the automated method was evaluated on the basis of nodule malignancy status, size, subtlety, and radiographic opacity.

MATERIALS AND METHODS

A database of 393 thick-section (10 mm) low-dose CT scans was collected. Automated lung nodule detection proceeds in two phases: gray-level thresholding for the initial identification of nodule candidates, followed by the application of a rule-based classifier and linear discriminant analysis to distinguish between candidates that correspond to actual lung nodules and candidates that correspond to non-nodules. Free-response receiver operating characteristic analysis was used to evaluate the performance of the method based on a jackknife training/testing approach.

RESULTS

An overall nodule detection sensitivity of 70% (330 of 470) was attained with an average of 1.6 false-positive detections per section. At the same false-positive rate, 83% (57 of 69) of the malignant lung nodules in the database were detected. When the method was trained specifically for malignant nodules, a sensitivity of 80% (55 of 69) was attained with 0.85 false-positives per section.

CONCLUSION

We have evaluated an automated lung nodule detection method with a large number of low-dose CT scans from a lung cancer screening program. An overall sensitivity of 80% for malignant nodules was achieved with 0.85 false-positive detections per section. Such a computerized lung nodule detection method is expected to become an important part of CT-based lung cancer screening programs.

Overexpression of S100A2 protein as a prognostic marker for patients with stage I non small cell lung cancer

S100A2, a calcium-binding protein, recently became of major interest because of its differential expression during transformation and metastasis in various tumors. The purpose of this study was to investigate the prognostic significance of S100A2 expression in the early-stage non small lung cancer (NSCLC). Immunohistochemical analysis to determine the percentage of cells staining positive for S100A2 was performed on 11 NSCLC tissue microarray slides containing samples from 113 patients with pathologic stage I NSCLC who had undergone curative surgery. S100A2 was expressed in samples from 79 patients (69.9%). Kaplan-Meier analysis showed that patients whose tumors had positive S100A2 expression had a significantly lower overall survival and disease-specific survival rate at 5 years after surgery than did patients with negative S100A2 expression (p < 0.001 and p < 0.001, respectively). Age at diagnosis, histologic type of cancer, degree of differentiation and smoking history did not have a statistically significant effect on survival. Multivariate analysis confirmed that S100A2 expression is a better predictor for disease-specific survival than were other clinical and histologic variables tested. Our results suggested that the expression of the S100A2 protein in stage I NSCLC indicates poor prognosis and may be used to identify patients with early-stage NSCLC who might benefit from adjuvant treatment.

The Natural History of Radiographically Occult Bronchogenic Squamous Cell Carcinoma

OBJECTIVE

An overdiagnosis bias occurs with the diagnosis of a disease that does not produce signs or symptoms before the patient dies from other causes. We sought to determine whether overdiagnosis bias is a factor when screening for squamous cell carcinoma of the lung.

DESIGN

Retrospective study of the Miyagi Population-Based Lung Cancer Screening Registry for high-risk patients who were seen between January 1, 1982 (when sputum cytology tests were added for men with long smoking histories), and December 31, 1996.

SETTING

Miyagi Prefecture, Japan.

PATIENTS

A total of 251 patients (all men) who had sputum cytology test results that were positive for squamous cell carcinoma but had normal radiograph findings, 44 of whom declined cancer treatment (mean age, 70 years) and 207 of whom were treated with resection within 12 weeks of diagnosis (mean age, 65.5 year).

END POINTS

Five-year and 10-year survival rates from primary lung cancer in both groups as of August 15, 2001.

RESULTS

Among the 44 untreated patients, 15 (34%) remained asymptomatic. The survival rate due to primary lung cancer death in the untreated group was 53.2% at 5 years and 33.5% at 10 years. The survival rate among treated patients was 96.7% at 5 years and 94.9% at 10 years. Of the 125 treated patients who died, 14 (11.2%) died from primary lung cancer.

CONCLUSION

Given that the two thirds of the untreated patients with squamous cell carcinoma of the bronchus died from lung cancer within 10 years, overdiagnosis bias does not appear to be a factor in screening for this disease. Thus, we recommend that patients with radiographically occult squamous cell carcinoma of the bronchus undergo tumor treatment after localization.

Screening for lung cancer

BACKGROUND

While population based screening for lung cancer has not been adopted by most countries, it is not clear whether sputum examinations, chest radiography or newer methods such as computed tomography are effective in reducing mortality from lung cancer.

OBJECTIVES

To determine whether screening for lung cancer using regular sputum examinations or chest radiography or CT chest reduces lung cancer mortality.

SEARCH STRATEGY

Electronic databases (the Cochrane Central Register of Controlled Trials, MEDLINE, PREMEDLINE and EMBASE; 1966 to July 2000) ), bibliographies, hand searching of a journal and discussion with experts were used to identify published and unpublished trials.

SELECTION CRITERIA

Controlled trials of screening for lung cancer using sputum examinations, chest radiography or CT chest.

DATA COLLECTION AND ANALYSIS

Intention to screen analysis was performed. Where there was significant statistical heterogeneity relative risks were reported using the random effects model, but for other outcomes the fixed effect model was used.

MAIN RESULTS

Seven trials were included (6 randomised controlled studies and 1 non-randomised controlled trial) with a total of 245,610 subjects. There were no studies with an unscreened control group. Frequent screening with chest x-rays was associated with an 11% relative increase in mortality from lung cancer compared with less frequent screening (RR 1.11, CI: 1.00-1.23). A non statistically significant trend was observed to reduced mortality from lung cancer when screening with chest x-ray and sputum cytology was compared with chest x-ray alone (RR 0.88, CI:0.74-1.03). Several of the included studies had potential methodological weaknesses. There were no controlled studies of spiral CT.

REVIEWER'S CONCLUSIONS

The current evidence does not support screening for lung cancer with chest radiography or sputum cytology. Frequent chest x-ray screening might be harmful. Further, methodologically rigorous trials are required.

Nonsmall-cell lung cancer: chemoprevention studies

Lung cancer is the leading cause of cancer-related death in the world. Tobacco is an addictive agent producing carcinogenic effects that have been extremely difficult to prevent or detect in a curable stage. Important randomized controlled studies have been published in "healthy" smokers (primary prevention); patients with early lesions, such as mucosal dysplasia/metaplasia (secondary prevention); and those who have already had definitive treatment for their first tobacco-related malignancy (tertiary prevention). To date, the results have been generally disappointing. It is critical to remember that lung cancer is usually diagnosed decades after the patient has begun or even stopped smoking. We must intervene with more effective agents or combinations of agents and do it earlier in the process of carcinogenesis. Approximately 10% of patients with lung cancer either never smoked or only were "passive" smokers due to their environment, workplace. These "never-smokers" may actually benefit from retinoids, while current smokers have not benefited from alpha-tocopherol, retinal, N-acetylcysteine, or isotretinoin. Smokers are actually harmed by the concurrent use of beta-carotene. We now have unprecedented knowledge regarding the control of cellular growth and senescence. New diagnostic tools also allow detection of smaller lesions. We must use all our knowledge of the cancer biology, new risk models, more refined intermediate markers, and modern detection tools to focus more clearly on the pathology of lung cancer and design research to ask more probing and relevant questions so we can begin to put an end to the worldwide scourge of this terrible killer.

Translational research in lung cancer

Recent research advances in cancer and molecular biology have furthered our understanding of the etiology and natural history of lung cancer. Through translational research, a growing understanding of the molecular changes that underlie cancer progression has contributed to the development of novel molecular approaches for early detection, further defining prognosis, refining treatment schedules, identifying new therapeutic targets, and identifying patients at risk for treatment-related toxicity from aggressive therapy, such as pneumonitis and esophagitis. In this article, we review progress in molecular/gene screening and prognosis, and we present a clinical study, based on preclinical research, in which we apply low-dose radiosensitizing paclitaxel for locally advanced non-small-cell lung cancer (NSCLC); this resulted in superior local tumor control while keeping treatment toxicity low. We also review progress made in identifying cytokines: interleukin [IL]-1alpha, IL-6, and transforming growth factor [TGF] beta as markers for lung cancer treatment-related radiation pneumonitis. Finally, we summarize different targeted therapy approaches and discuss their application to clinical trials. Irrespective of the slow progress toward clinical improvements, we have gained much knowledge through translational research using new molecular and biologic technology. We believe that knowledge of lung cancer biology will continue to provide the foundation for future improvements in lung cancer treatment.

The efficacy of lung cancer screening conducted in 1990s: four case-control studies in Japan

The efficacy of lung cancer screening is still controversial. In order to evaluate efficacy of mass screening for lung cancer in 1990s, the Japanese Ministry of Health and Welfare planned to conduct four independent case-control studies in four different regions; Miyagi, Gunma, Niigata, and Okayama Prefecture. The study design of all the four studies was a matched case-control study in which the decedents from lung cancer were defined as cases. In Gunma Prefecture, a screening examination is annual miniature chest X-ray only, whereas sputum cytology is added for high-risk screenees in others. Matching conditions were gender, year of birth, smoking histories (except Okayama), and municipality. Smoking adjusted odds ratio (OR) of dying from lung cancer for those screened within 12 months before case diagnosis compared with those not screened ranged 0.40-0.68. Three of four studies revealed statistically significant reduction of the risk for lung cancer death. OR of pooled analysis, where all sets were combined and analyzed, was 0.56 (95% confidence interval: 0.48-0.65). Recent mass screening program for lung cancer in Japan could reduce the risk for lung cancer death. However, the possibility exists that some confounding factors affected the results. In order to elucidate whether the results can be applied to Western countries, further studies will be required.

Lung cancer screening with low-dose CT

Screening for lung cancer is hoped to reduce mortality from this common tumour, which is characterised by a dismal overall survival, relatively well defined risk groups (mainly heavy cigarette smokers and workers exposed to asbestos) and a lack of early symptoms. In the past studies using sputum cytology and chest radiography have failed to demonstrate any reduction in lung cancer mortality through screening. One of the reasons is probably the relatively poor sensitivity of both these tests in early tumours. Low radiation dose computed tomography (CT) has been shown to have a much higher sensitivity for small pulmonary nodules, which are believed to be the most common presentation of early lung cancer. As, however, small pulmonary nodules are common and most are not malignant, non-invasive diagnostic algorithms are required to correctly classify the detected lesions and avoid invasive procedures in benign nodules. Nodule density, size and the demonstration of growth at follow-up have been shown to be useful in this respect and may in the future be supplemented by contrast-enhanced CT and positron emission tomography. Based on these diagnostic algorithms preliminary studies of low-dose CT in heavy smokers have demonstrated a high proportion of asymptomatic, early, resectable cancers with good survival. As, however, several biases could explain these findings in the absence of the ultimate goal of cancer screening, i.e. mortality reduction, most researchers believe that randomised controlled trials including several 10000 subjects are required to demonstrate a possible mortality reduction. Only then general recommendations to screen individuals at risk of lung cancer with low-dose CT should be made. It can be hoped that international cooperation will succeed in providing results as early as possible.

Lung nodule detection on thoracic computed tomography images: preliminary evaluation of a computer-aided diagnosis system

We are developing a computer-aided diagnosis (CAD) system for lung nodule detection on thoracic helical computed tomography (CT) images. In the first stage of this CAD system, lung regions are identified by a k-means clustering technique. Each lung slice is classified as belonging to the upper, middle, or the lower part of the lung volume. Within each lung region, structures are segmented again using weighted k-means clustering. These structures may include true lung nodules and normal structures consisting mainly of blood vessels. Rule-based classifiers are designed to distinguish nodules and normal structures using 2D and 3D features. After rule-based classification, linear discriminant analysis (LDA) is used to further reduce the number of false positive (FP) objects. We performed a preliminary study using 1454 CT slices from 34 patients with 63 lung nodules. When only LDA classification was applied to the segmented objects, the sensitivity was 84% (53/63) with 5.48 (7961/1454) FP objects per slice. When rule-based classification was used before LDA, the free response receiver operating characteristic (FROC) curve improved over the entire sensitivity and specificity ranges of interest. In particular, the FP rate decreased to 1.74 (2530/1454) objects per slice at the same sensitivity. Thus, compared to FP reduction with LDA alone, the inclusion of rule-based classification lead to an improvement in detection accuracy for the CAD system. These preliminary results demonstrate the feasibility of our approach to lung nodule detection and FP reduction on CT images.

Molecular detection approaches for smoking associated tumors

Smoking is directly responsible for approximately 90% of lung cancers and is also strongly associated with cancers of the head and neck, esophagus and urinary bladder. Our growing understanding of the molecular changes that underlie cancer progression has contributed to the development of novel molecular approaches for the detection of cancer. In this study, we review a number of recent studies that have used molecular techniques to detect neoplastic DNA from lung, head and neck, esophagus and bladder cancer. The majority of these approaches are based on polymerase chain reaction (PCR) based assays. These PCR-based techniques can detect a few clonal cancer cells containing a specific DNA mutation, microsatellite alteration, or CpG island methylation among an excess background of normal cells. The ability to accurately detect a small number of malignant cells in a wide range of clinical specimens including sputum, saliva, bronchoalveolar lavage fluid, urine, serum, plasma, or tissue has significant implications for screening high-risk individuals (such as cigarette smokers) for cancer.

The 'reservoir' of undetected bronchial carcinomas in the general population

STUDY OBJECTIVES

Autopsy studies have shown that a sizeable portion of lung cancers are never diagnosed and thus not entered into any cancer registry.

DESIGN

In 1997, we decided to make all available efforts to find all patients with lung cancer who had not been registered previously.

SETTING

The local hospitals in the county of Gävleborg, Sweden.

PATIENTS

All patients with lung cancer diagnosed in the county from 1997 to 2000.

INTERVENTIONS

In meetings with all the general practitioners of the county, these were asked to refer all suspected cases as early as possible, including those with a seemingly dismal prognosis. This initiative was also covered by the newspapers and the local television station.

MEASUREMENTS AND RESULTS

From 1997 onwards, the incidence of lung cancer in the county was found to be 40-50 per 100,000 inhabitants compared with an incidence of about 30 during the ten preceding years. This difference is significant in time (P<0.0001) and is compared with the incidence of lung cancers in four neighboring counties (P=0.002).

CONCLUSIONS

There can be a considerable number of patients with lung cancer who are never diagnosed. This can explain differences in survival between various countries and this will also affect the results of screening programs, since the control groups will also include a number of lung cancer cases which will never be recognized.

Screening for early lung cancer with low-dose spiral CT: prevalence in 817 asymptomatic smokers

PURPOSE

To present prevalence screening data from a nonrandomized screening trial by using low-dose computed tomography (CT) and a simple algorithm based on the size and attenuation of detected nodules to guide diagnostic work-up.

MATERIALS AND METHODS

Eight hundred seventeen asymptomatic volunteers (age range, 40-78 years; median age, 53 years; median tobacco consumption, 45 pack-years) underwent spiral low-dose CT of the chest without contrast material enhancement. We regarded all noncalcified pulmonary nodules greater than 10 mm in diameter as potentially malignant and recommended histologic examination or follow-up after 3, 6, 12, and 24 months to exclude growth. For noncalcified pulmonary nodules of 10 mm or smaller, repeat low-dose CT was recommended to exclude growth.

RESULTS

In 43% (350 of 817) of individuals, 858 noncalcified pulmonary nodules were found. Thirty-two nodules in 29 subjects were larger than 10 mm. Biopsy of 15 lesions revealed lung cancer in 12 lesions in 11 subjects (prevalence for all ages, 1.3% [11 of 817 subjects]; >50 years of age, 2.1% [11 of 519 subjects]; >60 years of age, 3.9% [eight of 206 subjects]), with a high proportion of early tumor stages (seven tumors, stage I; two, stage II; and three, stage III); three lesions were benign. In 17 nodules larger than 10 mm, follow-up with low-dose CT for a minimum of 24 months did not demonstrate growth.

CONCLUSION

Lung cancer screening with low-dose CT demonstrated a prevalence of asymptomatic cancers in 1.3% of a smoking population, including a high proportion of early tumor stages and a 20% (three of 15) rate of invasive procedures for benign lesions.

A case-control study of lung cancer screening in Okayama Prefecture, Japan

The effectiveness of lung cancer screening in reducing mortality still remains uncertain. In order to evaluate the efficacy of lung cancer screening, a case-control study was conducted in Okayama Prefecture, Japan. The study area consisted of 34 municipalities where a population-based lung cancer screening had been conducted. Chest X-ray examinations for all participants and sputum cytology for high-risk participants were offered annually. The cases analyzed in this study consisted of 412 individuals aged between 40 and 79 who died of lung cancer. A total of 3490 controls, two to ten for each case matched by gender, year of birth, and living district were randomly collected. Screening histories of cases were compared with those of and matched controls for the identical calendar period prio to diagnosis of the case. Smoking adjusted odds ratio (OR) of death from lung cancer for screened individuals versus unscreened, within 12 months before diagnosis, was calculated as 0.59 (95% confidence interval: 0.46-0.74; P=0.0001). The OR for women (0.39, 95% confidence interval: 0.24-0.64) was lower than that for men (0.67, 95% confidence interval: 0.51-0.87), although both were statistically significant. These results suggest that lung cancer screening contributes to reducing lung cancer mortality by 41%.

The role of photodynamic therapy in the management of stage I/II NSCLC

There is a resurgence of interest in lung cancer screening, motivated by the fact that many lung cancer patients cannot be cured due to advanced disease at presentation. Lung cancer screening may detect more early stage disease. Very early stage squamous cell type lung cancer in the central tracheobronchial tree can be detected and local bronchoscopic treatments such as photodynamic therapy can be applied if the tumor is strictly intraluminal and nodal disease is absent. So, accurate staging regarding tumor size and nodal disease is much more important than treatment per se. Bronchoscopic treatments are less morbid treatment alternatives than surgery and surgical bronchoplasty, especially for patients suffering from COPD and who have poor cardiovascular status due to their smoking history.

CT screening for lung cancer: not ready for routine practice

Lung cancer continues to be a major worldwide health problem. Multiple strategies are being explored in an attempt to reduce lung cancer mortality, including a renewed interest in screening. Multiple low-dose spiral computed tomography (CT) trials have been proposed, as proponents predict that small nodules will represent early-stage disease and detecting them will ultimately translate into improvements in outcomes. At this time, however, only prevalence-screening data are available, and it remains to be seen if CT will truly reduce mortality. The appropriate hypothesis-driven studies still must be performed and the results carefully analyzed before CT screening for lung cancer can be accepted as the standard of care.

Fluorescence bronchoscopy for early detection of lung cancer: a clinical perspective

The conventional method of bronchoscopy has only a 30% sensitivity to detect early stage cancer in the central airways. For patients with positive sputum cytology who clearly harbor early cancers, repeat and lengthy sessions of bronchoscopies are required for accurate localization of these lesions. This leads to a significant delay in obtaining the diagnosis, postponing an appropriate treatment and reduces the chance for cure. There are valid reasons for improving the detection rate of early stage lung cancers. The number of individuals at risk forms a large population, the outcome of patients treated with early stage cancer has been shown to be better and bronchoscopic treatments, e.g. photodynamic therapy and electrocautery, are currently alternatives for surgical resection. Finding more early stage cancers by screening the population at risk and accurate staging to enable treatment at the earliest stage feasible, may improve the dismal prognosis of many patients. This article deals with the clinical background and current problems in early detection of lung cancer and discusses our expectations regarding new developments in bronchoscopy for early detection, accurate staging and treatment of lung cancer.

Fluorescence versus white-light bronchoscopy for detection of preneoplastic lesions: a randomized study

BACKGROUND

There are no currently approved methods for the screening and early detection of lung cancer. We compared the ability of conventional white-light bronchoscopy (WLB) and laser-induced fluorescence endoscopy (LIFE) to detect preneoplastic lung lesions in a randomized trial in which both the order of the procedures and the bronchoscopists were randomly assigned.

METHODS

The study included high-risk subjects enrolled because of a cigarette smoking history of at least 30 pack-years, an air-flow obstruction, and either an abnormal sputum cytology (n = 48) or a previous or suspected lung cancer (n = 7). LIFE and WLB were performed on all patients. Biopsy specimens were assessed for histologic abnormalities, including the presence of angiogenic squamous dysplasia. All statistical tests were two-sided.

RESULTS

A total of 391 biopsy specimens were taken from the 55 patients. Thirty-two patients (58%; 95% confidence interval [CI] = 44% to 71%) had at least one biopsy with moderate or severe dysplasia, and 19 (59%; 95% CI = 41% to 76%) of these patients could be diagnosed based solely on the results of LIFE. LIFE was statistically significantly more sensitive than WLB for detecting moderate dysplasia or worse (68.8% versus 21.9%, respectively) (difference = 46.9%; 95% CI = 25% to 68%; P< .001). The relative sensitivities (WLB = 1.0) were 3.1 (95% CI = 1.6 to 6.3) for LIFE and 3.7 (95% CI = 1.9 to 7.3) for LIFE and WLB combined. LIFE was less specific than WLB (69.6% versus 78.3%, respectively; P = .45), but the difference was not statistically significant. The relative specificities (WLB = 1.0) were 0.9 for LIFE (95% CI = 0.6 to 1.3) and 0.6 (95% CI = 0.4 to 1.0) for LIFE and WLB combined. The results were similar regardless of the order of the procedures or the order of the bronchoscopists. Also, LIFE was better at identifying angiogenic squamous dysplasia lesions than WLB (detection ratio [DR], which indicates the relative likelihood of getting a positive result in a sample with dysplasia compared with one without, for LIFE = 1.39 [95% CI = 1.17 to 1.65] versus DR for WLB = 0.67 [95% CI = 0.38 to 1.21]).

CONCLUSION

LIFE was more sensitive than WLB in detecting preneoplastic bronchial changes in high-risk subjects. The prognostic implication of this finding is not yet clear.