The use of genetic markers to identify lung cancer in fine needle aspiration samples

PURPOSE

We seek to establish a genetic test to identify lung cancer using cells obtained through computed tomography-guided fine needle aspiration (FNA).

EXPERIMENTAL DESIGN

We selected regions of frequent copy number gains in chromosomes 1q32, 3q26, 5p15, and 8q24 in non-small cell lung cancer and tested their ability to determine the neoplastic state of cells obtained by FNA using fluorescent in situ hybridization. Two sets of samples were included. The pilot set included six paraffin-embedded, noncancerous lung tissues and 33 formalin-fixed FNA specimens. These 39 samples were used to establish the optimal fixation and single scoring criteria for the samples. The test set included 40 FNA samples. The results of the genetic test were compared with the cytology, pathology, and clinical follow-up for each case to assess the sensitivity and specificity of the genetic test.

RESULTS

Nontumor lung tissues had < or= 4 signals per nucleus for all tested markers, whereas tumor samples had > or = 5 signals per nucleus in five or more cells for at least one marker. Among the 40 testing cases, 36 of 40 (90%) FNA samples were analyzable. Genetic analysis identified 15 cases as tumor and 21 cases as nontumor. Clinical and pathologic diagnoses confirmed the genetic test in 15 of 16 lung cancer cases regardless of tumor subtype, stage, or size and in 20 of 20 cases diagnosed as benign lung diseases.

CONCLUSIONS

A set of only four genetic markers can distinguish the neoplastic state of lung lesion using small samples obtained through computed tomography-guided FNA.

Assessment of radiologist performance in the detection of lung nodules: dependence on the definition of "truth"

RATIONALE AND OBJECTIVES

Studies that evaluate the lung nodule detection performance of radiologists or computerized methods depend on an initial inventory of the nodules within the thoracic images (the "truth"). The purpose of this study was to analyze (1) variability in the "truth" defined by different combinations of experienced thoracic radiologists and (2) variability in the performance of other experienced thoracic radiologists based on these definitions of "truth" in the context of lung nodule detection in computed tomographic (CT) scans.

MATERIALS AND METHODS

Twenty-five thoracic CT scans were reviewed by four thoracic radiologists, who independently marked lesions they considered to be nodules >or=3 mm in maximum diameter. Panel "truth" sets of nodules were then derived from the nodules marked by different combinations of two and three of these four radiologists. The nodule detection performance of the other radiologists was evaluated based on these panel "truth" sets.

RESULTS

The number of "true" nodules in the different panel "truth" sets ranged from 15 to 89 (mean 49.8 +/- 25.6). The mean radiologist nodule detection sensitivities across radiologists and panel "truth" sets for different panel "truth" conditions ranged from 51.0 to 83.2%; mean false-positive rates ranged from 0.33 to 1.39 per case.

CONCLUSIONS

Substantial variability exists across radiologists in the task of lung nodule identification in CT scans. The definition of "truth" on which lung nodule detection studies are based must be carefully considered, because even experienced thoracic radiologists may not perform well when measured against the "truth" established by other experienced thoracic radiologists.

Plasma carbonyls do not correlate with lung function or computed tomography measures of lung density in older smokers

Oxidative stress and inflammation are hallmarks of chronic obstructive pulmonary disease (COPD). A critical byproduct of oxidative damage is the introduction of carbonyl groups into amino acid residues. We hypothesize that plasma carbonyl content is inversely correlated with lung function and computed tomography (CT) measures of lung density among smokers and is elevated in COPD. Carbonyl was measured in plasma of participants aged 60 years and older by ELISA. Generalized linear and additive models were used to adjust for potential confounders. Among 541 participants (52% male, mean age 67 years, 41% current smokers), mean plasma carbonyl content was 17.9+/-2.9 nmol ml(-1) and mean forced expiratory volume in one second (FEV(1)) was 80.7+/-20.9% of predicted. Plasma carbonyl content was inversely associated with FEV(1), but this relationship was largely explained by age. Multivariate analyses ruled out clinically meaningful associations of plasma carbonyl content with FEV(1), FEV(1)/FVC (forced vital capacity) ratio, severity of airflow obstruction, and CT lung density. Plasma carbonyl content is a poor biomarker of oxidative stress in COPD and emphysema.

Increased uptake of 18F-fluorodeoxyglucose due to Mycobacterium avium complex in a solitary pulmonary nodule

A 59-year-old woman with a history of both breast and lung cancer developed a new 1.5 cm solitary pulmonary nodule on computed tomography (CT) scan. The nodule had increased 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) with a standard uptake value (SUV) of 3.4. A CT guided biopsy was performed, and Mycobacterium avium complex (MAC) was identified. PET scans have become an important part of the diagnosis, staging, and follow-up of cancer. Even in individuals at considerable risk for cancer with a solitary nodule demonstrating increased FDG uptake, further diagnostic evaluation and needle biopsy might receive consideration prior to surgical intervention.

The Lung Image Database Consortium (LIDC): ensuring the integrity of expert-defined "truth"

RATIONALE AND OBJECTIVES

Computer-aided diagnostic (CAD) systems fundamentally require the opinions of expert human observers to establish "truth" for algorithm development, training, and testing. The integrity of this "truth," however, must be established before investigators commit to this "gold standard" as the basis for their research. The purpose of this study was to develop a quality assurance (QA) model as an integral component of the "truth" collection process concerning the location and spatial extent of lung nodules observed on computed tomography (CT) scans to be included in the Lung Image Database Consortium (LIDC) public database.

MATERIALS AND METHODS

One hundred CT scans were interpreted by four radiologists through a two-phase process. For the first of these reads (the "blinded read phase"), radiologists independently identified and annotated lesions, assigning each to one of three categories: "nodule >or=3 mm," "nodule <3 mm," or "non-nodule >or=3 mm." For the second read (the "unblinded read phase"), the same radiologists independently evaluated the same CT scans, but with all of the annotations from the previously performed blinded reads presented; each radiologist could add to, edit, or delete their own marks; change the lesion category of their own marks; or leave their marks unchanged. The post-unblinded read set of marks was grouped into discrete nodules and subjected to the QA process, which consisted of identification of potential errors introduced during the complete image annotation process and correction of those errors. Seven categories of potential error were defined; any nodule with a mark that satisfied the criterion for one of these categories was referred to the radiologist who assigned that mark for either correction or confirmation that the mark was intentional.

RESULTS

A total of 105 QA issues were identified across 45 (45.0%) of the 100 CT scans. Radiologist review resulted in modifications to 101 (96.2%) of these potential errors. Twenty-one lesions erroneously marked as lung nodules after the unblinded reads had this designation removed through the QA process.

CONCLUSIONS

The establishment of "truth" must incorporate a QA process to guarantee the integrity of the datasets that will provide the basis for the development, training, and testing of CAD systems.

The Lung Image Database Consortium (LIDC): an evaluation of radiologist variability in the identification of lung nodules on CT scans

RATIONALE AND OBJECTIVES

The purpose of this study was to analyze the variability of experienced thoracic radiologists in the identification of lung nodules on computed tomography (CT) scans and thereby to investigate variability in the establishment of the "truth" against which nodule-based studies are measured.

MATERIALS AND METHODS

Thirty CT scans were reviewed twice by four thoracic radiologists through a two-phase image annotation process. During the initial "blinded read" phase, radiologists independently marked lesions they identified as "nodule >or=3 mm (diameter)," "nodule <3 mm," or "non-nodule >or=3 mm." During the subsequent "unblinded read" phase, the blinded read results of all four radiologists were revealed to each radiologist, who then independently reviewed their marks along with the anonymous marks of their colleagues; a radiologist's own marks then could be deleted, added, or left unchanged. This approach was developed to identify, as completely as possible, all nodules in a scan without requiring forced consensus.

RESULTS

After the initial blinded read phase, 71 lesions received "nodule >or=3 mm" marks from at least one radiologist; however, all four radiologists assigned such marks to only 24 (33.8%) of these lesions. After the unblinded reads, a total of 59 lesions were marked as "nodule >or=3 mm" by at least one radiologist. Twenty-seven (45.8%) of these lesions received such marks from all four radiologists, three (5.1%) were identified as such by three radiologists, 12 (20.3%) were identified by two radiologists, and 17 (28.8%) were identified by only a single radiologist.

CONCLUSION

The two-phase image annotation process yields improved agreement among radiologists in the interpretation of nodules >or=3 mm. Nevertheless, substantial variability remains across radiologists in the task of lung nodule identification.

Incidence and cytological features of pulmonary hamartomas indeterminate on CT scan

OBJECTIVE

Pulmonary hamartomas have a characteristic heterogeneous radiological appearance. However, when composed predominantly of undifferentiated mesenchymal fibromyxoid component, their homogeneous appearance on computed tomography is indeterminate for malignancy. Rendering an accurate preoperative diagnosis in these cases can alter management. The aim of this study was to determine the incidence and accuracy of cytodiagnosis for hamartomas 'indeterminate' by imaging.

METHODS

We retrospectively reviewed records for hamartomas diagnosed by transthoracic fine needle aspiration (FNA) including immediate impressions and final diagnoses. Cytological features evaluated included the presence of fibromyxoid stroma, bronchioloalveolar cell hyperplasia, fibroadipose tissue, cartilage and smooth muscle.

RESULTS

Eighteen (1.3%) hamartomas were identified from 1355 transthoracic FNAs. The immediate impression was hamartoma in 13 (72%), carcinoid in one (6%), mucinous bronchioloalveolar carcinoma in two (11%) and non-diagnostic in two (11%). The final diagnosis of hamartoma in cases diagnosed as carcinoid, mucinous bronchioloalaveolar carcinoma and non-diagnostic on immediate impression was rendered following assessment of all cytological material.

CONCLUSION

Overall, FNAs are highly reliable for diagnosing hamartomas even when composed principally of undifferentiated mesenchymal fibromyxoid stroma, especially with the aid of all available preparations including Diff-Quik smears, Papanicolaou smears, ThinPreps and cell block material.

Bronchioloalveolar carcinoma and lung adenocarcinoma: the clinical importance and research relevance of the 2004 World Health Organization pathologic criteria

INTRODUCTION

Advances in the pathology and computed tomography (CT) of lung adenocarcinoma and bronchioloalveolar carcinoma (BAC) have demonstrated important new prognostic features that have led to changes in classification and diagnostic criteria.

METHODS

The literature and a set of cases were reviewed by a pathology/CT review panel of pathologists and radiologists who met during a November 2004 International Association for the Study of Lung Cancer/American Society of Clinical Oncology consensus workshop in New York. The group addressed the question of whether sufficient data exist to modify the 2004 World Health Organization (WHO) classification of adenocarcinoma and BAC to define a "minimally invasive" adenocarcinoma with BAC. The problems of diffuse and/or multicentric BAC and adenocarcinoma were evaluated.

RESULTS

The clinical concept of BAC needs to be reevaluated with careful attention to the new 2004 WHO criteria because of the major clinical implications. Existing data indicate that patients with solitary, small, peripheral BAC have a 100% 5-year survival rate. The favorable prognostic impact of the restrictive criteria for BAC is already being detected in major epidemiologic data sets such as the Surveillance Epidemiology and End-Results registry. Most lung adenocarcinomas, including those with a BAC component, are invasive and consist of a mixture of histologic patterns. Therefore, they are best classified as adenocarcinoma, mixed subtype. This applies not only to adenocarcinomas with a solitary nodule presentation but also to tumors with a diffuse/multinodular pattern. The percentage of BAC versus invasive components in lung adenocarcinomas seems to be prognostically important. However, at the present time, a consensus definition of "minimally invasive" BAC with a favorable prognosis was not recommended by the panel, so the 1999/2004 WHO criteria for BAC remain unchanged. In small biopsy specimens or cytology specimens, recognition of a BAC component is possible. However, it is not possible to exclude an invasive component. The diagnosis of BAC requires thorough histologic sampling of the tumor.

CONCLUSION

Advances in understanding of the pathology and CT features of BAC and adenocarcinoma have led to important changes in diagnostic criteria and classification of BAC and adenocarcinoma. These criteria need to be uniformly applied by pathologists, radiologists, clinicians, and researchers. The 2004 WHO classification of adenocarcinoma is readily applicable to research studies, but attention needs to be placed on the relative proportion of the adenocarcinoma subtypes. Other recently recognized prognostic features such as size of scar, size of invasive component, or pattern of invasion also seem to be important. More work is needed to determine the most important prognostic pathologic features in lung adenocarcinoma.

CT Screening for Lung Cancer:Prevalence and Incidence of Mediastinal Masses

PURPOSE

To determine the frequency and natural course of mediastinal masses in asymptomatic people at high risk for lung cancer who were undergoing computed tomographic (CT) screening.

MATERIALS AND METHODS

Informed consent and institutional review board approval for this HIPAA-compliant study were obtained at each participating institution. All documented mediastinal masses among the 9263 baseline and 11 126 annual repeat screenings performed in the Early Lung Cancer Action Project (ELCAP) and its successor project, the New York ELCAP, were identified. Two radiologists confirmed all cases, identified the location and measured the diameter (average of length and width) of each mass, and reviewed all subsequent CT and clinical and surgical results. The prevalence and incidence of mediastinal masses were then determined.

RESULTS

Of the 9263 individuals, 71 had a mediastinal mass seen at baseline screening (prevalence of 0.77%). Of the 71 masses, 41 were thymic, 16 were thyroidal, two were esophageal cancers, six were tracheal-esophageal diverticula, and six were other masses. Among the 11 126 annual repeat screenings, only one new mediastinal mass was identified (incidence of 0.01%). This suggests a long average duration for mediastinal masses in asymptomatic people. Among the 41 thymic masses, five were larger than 3.0 cm in diameter, and all five were resected; of these five, one was a thymic carcinoma and four were noninvasive thymomas. Of the remaining 36 thymic masses, 25 were evaluated at follow-up CT 1 year later: Five had increased in diameter, two had decreased, and 18 remained unchanged. All 16 thyroid masses were due to goiter; none of these were changed at follow-up CT 1 year later.

CONCLUSION

Mediastinal masses found in the context of CT screening for lung cancer in asymptomatic people should be approached in a "conservative" manner; this includes thymic masses smaller than 3 cm in diameter, as most of these remain unchanged or even decrease in size.

Estimating the growth rates of primary lung tumours from samples with missing measurements

A method to estimate the population variability in tumour growth rate using incomplete data was developed. We assume exponential growth and lognormal distribution for the parameter of the growth curve. Estimates of growth rate obtained based on the cases with two measurements, one of which is obtained retrospectively, are biased towards lower growth rate. For the data sets where two measurements are available for some tumours and only one measurement for others (which means that no tumour was seen in retrospect for those cases), several approaches were developed that can eliminate or substantially reduce the bias. The relative error of the best estimates, as assessed by simulation, rarely exceeds 20 per cent. We found that the results of application of our estimation procedures to chest X-ray screening data agree well with the expectations.

Evolving Concepts in the Pathology and Computed Tomography Imaging of Lung Adenocarcinoma and Bronchioloalveolar Carcinoma

Purpose

To review recent advances in pathology and computed tomography (CT) of lung adenocarcinoma and bronchioloalveolar carcinoma (BAC).

Methods

A pathology/CT review panel of pathologists and radiologists met during a November 2004 International Association for the Study of Lung Cancer/American Society of Clinical Oncology consensus workshop in New York. The purpose was to determine if existing data was sufficient to propose modification of criteria for adenocarcinoma and BAC as newly published in the 2004 WHO Classification of Lung Tumors, and to address the pathologic/radiologic concept of diffuse/multicentric BAC.

Results

Solitary small, peripheral BACs have an excellent prognosis. Most lung adenocarcinomas with a BAC pattern are not pure BAC, but rather adenocarcinoma, mixed subtype with invasive patterns. This applies to tumors presenting with a diffuse/multinodular as well as solitary nodule pattern. The percent of BAC versus invasive components in lung adenocarcinomas appears to be prognostically important. However, a consensus definition of “minimally invasive” BAC with a favorable prognosis could not be achieved. While recognition of a BAC component is possible, the diagnosis of BAC with exclusion of invasive adenocarcinoma cannot be made by small biopsy or cytology specimens.

Conclusion

There is a need to work toward a mutual understanding and consensus between pathologists, clinicians, and researchers with the use of the term BAC versus adenocarcinoma. Future studies should make some attempt to quantitate these components and/or other features such as size of scar, size of invasive component, or pattern of invasion. Hopefully, this work will allow definition of a category of adenocarcinoma, mixed subtype with predominant BAC/minimal invasion and a favorable prognosis.

Stage of Lung Cancer in Relation to Its Size*

OBJECTIVE

To assess the relationship between tumor size and disease stage at the time of diagnosis in non-small cell lung cancer.

METHODS

From the Surveillance, Epidemiology and End Results registry, we identified all cases of primary non-small cell lung cancer diagnosed prior to autopsy. Among these, we focused on 84,152 cases diagnosed in 1988 or later and documented as to tumor size and disease stage at diagnosis. The distribution of disease stage within categories of tumor size was determined.

RESULTS

The smaller the tumor was, the more likely the disease was stage I. For tumors < 15 mm in diameter, the proportion of stage I was 54%, compared with 46% for 16 to 25 mm, 34% for 26 to 35 mm, 25% for 36 to 45 mm, and 15% for cases > 45 mm, with all of these proportions being very precise.

CONCLUSIONS

Tumor size has substantial bearing on disease stage in non-small cell lung cancer.

The effect of tumor size on curability of stage I non-small cell lung cancers

OBJECTIVE

The objective of this study was to determine the relationship between tumor size and curability of stage I non-small cell lung cancer.

METHODS

From the Surveillance, Epidemiology, and End Results registry 2003, we identified all primary non-small cell lung cancer cases that were diagnosed prior to autopsy. Among these cases, we narrowed the focus to those diagnosed in 1988 or later, and to 7,620 patients who had undergone curative surgical resection. Kaplan-Meier survival curves were obtained for these stage I malignancies for five tumor size categories (ie, 5 to 15 mm, 16 to 25 mm, 26 to 35 mm, 36 to 45 mm, and > 45 mm). The 12-year Kaplan-Meier estimator of survival was used as a measure of lung cancer cure rate.

RESULTS

Among 7,620 stage I cancers, cure rates decreased with increasing tumor size. The 12-year survival rates for patients with tumors 5 to 15 mm in diameter was 69% (95% confidence interval [CI], 64 to 74%), 63% for those with tumors 16 to 25 mm in diameter (95% CI, 60 to 67%), 58% for those with tumors 26 to 35 mm in diameter (95% CI, 54 to 61%), 53% for those with tumors 36 to 45 mm in diameter (95% CI, 48 to 57%), and 43% for those with tumors > 45 mm in diameter (95% CI, 39 to 48%). Cure rates were statistically significantly different for all tumor size categories (p < 0.05) except for the groups with tumors 26 to 35 mm and 36 to 45 mm in diameter (p = 0.10).

CONCLUSIONS

Smaller tumor size at diagnosis is associated with improved curability within stage I non-small cell lung cancers. These results suggest that further subclassification by size within stage I may be important.

State-of-the-art screening for lung cancer: (part 2): CT scanning

There have been dramatic improvements in technology in the past decade. In conjunction there have also been advances in our clinical knowledge that have led to changes in the screening regimen. These changes are expected to continue in the future as CT scanners continue to improve and knowledge about screening accumulates, and computer-assisted techniques are expected to play an ever more important role. This dynamic process will lead to continued improvements in the diagnostic distribution of lung cancers detected under CT screening.