Screening for lung cancer: time to think positive

Exploration of differentially expressed plasma proteins in patients with lung adenocarcinoma using iTRAQ-coupled 2D LC-MS/MS

BACKGROUND

Lung adenocarcinoma is characterized by early asymptomatic progression and metastasis. Appearance of respiratory symptoms usually means the disease is aggravated. The aim of this study was to identify the protein profile in plasma of lung adenocarcinoma of stages I-IV, and look for novel diagnostic biomarkers.

METHODS

Isobaric tags for relative and absolute quantification (iTRAQ) coupled with two dimensional liquid chromatography - tandem mass spectrometry technology (2D LC-MS/MS) was applied to separate and identify differential expression of proteins in plasma specimens from 10 healthy individuals, 10 patients with pneumonia, 7 patients with lung adenocarcinoma of stages I-II, respectively, and 10 patients with lung adenocarcinoma of stages III-IV, then analyze the functions of the differential expression of proteins by bioinformatics.

RESULTS

ADAMTS-like protein 4, Fibrinogen-like protein 1 precursor, secretoglobin family 3A member 2 and haptoglobin were up-regulated in patients with lung adenocarcinoma by proteomics analysis, and the expression levels of SCGB3A2 and Hp by ELISA were consistent. Pathway analysis of identified differential expression of proteins showed they were mainly involved in chemokine/p53/TGF-beta signaling pathway.

CONCLUSIONS

Plasma SCGB3A2 is a potential maker for diagnosis of primary pulmonary adenocarcinoma. Abnormal post-translational protein modification may be associated with the progression of lung cancer.

Effect of multiscale processing in digital chest radiography on automated detection of lung nodule with a computer assistance system

The aim of this study is to evaluate the effect of multiscale processing in digital chest radiography on automated detection of lung nodule with a computer-aided diagnosis (CAD) system. The study involved 58 small-nodule patient cases and 58 normal cases. The 58 patient cases included a total of 64 noncalcified lung nodules up to 15 mm in diameter. Each case underwent an examination with a digital radiography system (Digital Diagnost, Philips Medical Systems), and the acquired image was processed by the following three types of multiscale processing (Unique Image Processing Package, Philips Medical Systems) respectively: (1) standard image from the default processing parameter (structure preference, 0.0), (2) high-pass image with structure preference of 0.4, (3) low-pass image with structure preference of -0.4. The CAD output images were produced with a real-time computer assistance system (IQQAtrade mark-Chest, EDDA Technology). Two experienced chest radiologists established the nodule gold standard by consensus reading according to computed tomography results, and analyzed and recorded the detection of lung nodules and false-positive detections of these CAD output images. For the entire cases involved (each case with three types of different processing), a total of 348 observations were evaluated by the receiver operating characteristic (ROC) analysis. The mean area under the ROC curve (A ( z )) value was 0.700 for the standard images, 0.587 for the high-pass images, and 0.783 for the low-pass images. There were statistically significant A (z) values among these three types of processed images (p < 0.01). Multiscale processing in digital chest radiography can affect the automated detection of lung nodule by CAD, which is consistent with effects from visual inspection.

Population screening for lung cancer

The feasibility of diagnosing small stage 1 lung cancers using low-dose chest computed tomography in asymptomatic at-risk individuals has been demonstrated in multiple studies. However, it has yet to be proved that the introduction of a chest computed tomography screening programme would do more good than harm at an acceptable cost.

Lung cancer screening: will the controversy extend to its cost-effectiveness?

Lung cancer is the second most common cancer and the leading cause of cancer-related deaths in the US. It has been shown that when treated in its early stages, survival rates improve. Despite this, controversy remains regarding screening for the early detection of lung cancer, primarily because mortality reductions were not observed in the trials that studied chest x-ray and sputum cytology. Nevertheless, renewed interest in screening, due in part to better screening options, has prompted further research exploring the potential cost-effectiveness of implementing lung cancer screening programs. This article provides a critical review of the literature of economic evaluations of lung cancer screening programs. The focus of this review is the methodology implemented in these studies. Based on an electronic search of the literature (Pubmed, Medline and CancerLit) from Sep 1988-Sep 2001, seven articles that quantified the cost-effectiveness of lung cancer screening programs were identified. For most of the studies, the cost-effectiveness aspect was a minor component with little or no description of the methods. Although some studies focused more on estimating the economic efficiency of screening, their methodology was weak and still not well documented. Only two studies implemented fully a cost-effectiveness analysis and provided the necessary level of detail. If consensus can be reached regarding the clinical benefit of lung cancer screening, future studies related to cost-effectiveness would have to be implemented on much sounder methodology. The publications reviewed do provide preliminary support for the economic efficiency of screening for lung cancer.

Smoking status, occupational asbestos exposure and bronchial location of lung cancer

The objective of this study was to determine the factors associated with central airway versus peripheral bronchial location of lung cancer. All patients diagnosed with lung cancer from 1997 through 2000 in the Respiratory Disease Department of Rouen University Hospital were prospectively interviewed about their smoking and occupational history using a standardized questionnaire. All patients underwent white-light bronchial endoscopy using a 4.5 mm flexible endoscope. Tumors were classified as central when they were accessible and visible using this technique. Out of 217 cases of lung cancer included in this study, 155 (71%) were central. Histological type of lung cancer was strongly associated with bronchial location as central location was observed in 48, 82 and 92% of Adenocarcinoma (AC), Squamous Cell (SqC), and Small Cell Carcinoma (SCC), respectively (P<0.0001). Among non asbestos-exposed patients, location varied little with smoking status, with central location frequency ranging from 74 to 80%. In contrast, lung cancer was recorded central in 41% of long-term (> or =10 years) ex-smokers, 67% of short-term (<10 years) ex-smokers and 75% of current smokers (P=0.04) among patients exposed to asbestos, suggesting an interaction between duration of smoking cessation and occupational asbestos exposure with respect to lung cancer location. These findings were confirmed after adjustment for sex, age and histologic type in multivariate analysis. These results suggest that individually-tailored multimodality screening strategies relying on various combinations of low-dose CT scan, sputum analysis and fluorescence endoscopy according to each patient's profile may be more effective than standard strategies based on a single approach for all patients.

Management of the solitary pulmonary nodule: directed resection

The primary goals in management of a solitary pulmonary nodule are: 1) early detection and treatment of lung cancer at a curable stage; 2) avoidance of unnecessary surgery for benign lesions; 3) efficient, economic use of resources in distinguishing between benign and malignant lesions. Management depends on the nature of the nodule, the nature of the patient, and the approach of the physician or surgeon who assumes responsibility for further evaluation and treatment of the solitary pulmonary nodule. By combining appropriate diagnostic studies, and close personal attention, unnecessary excision of benign nodules can be kept to a minimum, patient anxiety allayed and excision of cancers undertaken with appropriate staging and without compromise of outcome.

Diagnosis of roentgenographically occult lung cancer by sputum cytology

The specialty has the knowledge and technology to change the outcome of lung cancer. Lung cancer, diagnosed in early stages, is as curable as all other cancers. Sputum cytology is the initial step in diagnosing roentgenographically occult lung cancer. Sputum cytology is complementary to CT scanning. Sputum cytology identifies small central lesions, and CT scanning discovers peripheral tiny adenocarcinomas.

Prospective study on video-assisted thoracoscopic surgery in the resection of pulmonary nodules: 209 cases from the Spanish Video-Assisted Thoracic Surgery Study Group

OBJECTIVE

The diagnosis of pulmonary nodules has become one of the main indications of video-assisted thoracoscopic surgery (VATS), especially for small nodules not accessible by bronchoscopy or by percutaneous transthoracic needle aspiration. In this study we evaluate the indications, diagnostic safety, complications, and technical difficulty of VATS in the diagnosis of pulmonary nodules in Spain.

MATERIALS AND METHODS

We conducted a prospective study of 209 patients with one or more pulmonary nodules from a group of Spanish thoracic surgery divisions (The Spanish Video-assisted Thoracic Surgery Study Group). Data was collected and evaluated on variables contained on a questionnaire including demographic information, characteristics of the nodules, identification methods, surgical technique, morbidity and mortality rates, and diagnostic yield.

RESULTS

The mean size of the nodules was 1.9 cm (range 0.3-5 cm). A total of 93.3% were peripheral. A diagnosis was established in 100% of the cases. In this study, 51.1% of lesions were benign and 48.8% were malignant. In 16.3% of cases, a conversion to thoracotomy was needed. The morbidity was 9.6% and the mortality 0.5%. We found a relationship between the size of a nodule and a diagnosis of malignancy (P=0.019) and between a central location and a need to convert to thoracotomy (P=0.002). Patients with nodules >2 cm had a greater risk of complications (P=0.0001).

CONCLUSIONS

In the diagnosis of pulmonary nodules, VATS has a specificity of 100% and a low mortality rate. The probability of developing complications is higher when the nodule is >2 cm.

Reproducibility of the WHO/IASLC grading system for pre-invasive squamous lesions of the bronchus: a study of inter-observer and intra-observer variation

AIMS

Although many workers have graded pre-invasive squamous lesions arising in the bronchus, there has been no consensus classification system until the latest edition of the WHO/IASLC histological classification of pulmonary and pleural tumours. Because the value of any such system is dependent on its reproducibility, we have circulated a series of such lesions to a panel of histopathologists to assess interobserver and intra-observer variation when the WHO/IASLC classification was applied.

METHODS AND RESULTS

Colour transparencies of 28 pre-invasive squamous lesions were assessed by six histopathologists (two with a special interest in pulmonary pathology, two generalists and two trainees) on three separate occasions over a period of 3 months, using the criteria of the WHO/IASLC (mild, moderate and severe dysplasia, and in-situ carcinoma). An additional category of metaplasia was added for those cases that showed no dysplasia. Weighted kappa coefficents of agreement (K(w)) were used to evaluate paired observations with a standard quadratic weighting being employed, such that kappa coefficients corresponded to intra-class correlation coefficients. Wilcoxon's sign-ranked test was used to measure the statistical significance of group trends, when comparing kappa values for the three grading systems. Various 3-point systems were also assessed, through combination of the above groups. Intra-observer agreement was substantially better than interobserver variation (mean: 0.71 vs. 0.55). Between the various pathologist groups, inter-observer variation was relatively minor, although intra-observer variation was higher within the trainee pathologist group. Using weighted kappa values, there was no significant difference in either inter-observer or intra-observer agreement between the five point grading system and a 3-point system of metaplasia/mild, moderate and severe/in-situ grades. However, there was a significant increase in variation when a 3-point system of metaplasia/mild, moderate/severe and in-situ carcinoma was used.

CONCLUSION

This study shows levels of interobserver and intra-observer variation similar to those found in other grading systems in histopathology, with no significant decrease in variability found by abridging the system. The WHO/IASLC system is therefore recommended for future use in both clinical and research fields.

Trends in survival for patients diagnosed with cancer in Vaud, Switzerland, between 1974 and 1993

BACKGROUND

Analysis of trends in cancer survival in defined well surveilled populations can provide useful indications on advancements in cancer management and treatment.

PATIENTS AND METHODS

Survival rates from the Vaud Cancer Registry were computed for 31,158 cases registered in 1984-1993, and compared with those registered in 1974-1978 and 1979-1983.

RESULTS

A systematic, albeit generally moderate, tendency towards increasing five-year relative survival was observed for both sexes and most major cancer sites, including oral cavity and pharynx (0.38-0.43). stomach (0.21-0.26), colon (0.49-0.55), rectum (0.45-0.51), lung (0.08-0.12), skin melanoma (0.67-0.89), female breast (0.67-0.80), endometrium (0.72-0.84), ovary (0.28-0.37). prostate (0.44-0.66), testis (0.73-0.96), bladder (0.31-0.50), kidney and renal pelvis (0.41-0.59), thyroid (0.73-0.81), non-Hodgkin's lymphomas (0.37-0.63), Hodgkin's disease (0.61-0.81), and leukaemias (0.27-0.39). Survival for all cancers and both sexes combined, rose from 0.51 0.64 (0.57 for males, 0.71- for females). No appreciable change in survival was observed for cancers of oesophagus, liver, gallbladder, pancreas, larynx, cervix uteri, brain, multiple myeloma, as well as unidentified or unknown origin neoplasms.

CONCLUSIONS

Survival estimates for most cancer sites are comparable to the US SEER dataset, and their pattern of trends are discussed in terms of improved diagnosis and treatment for various neoplasms.

Prospects for progress in diagnostic imaging

New fast-imaging MRI systems designed specifically for cardiac magnetic resonance enable new applications of noninvasive vascular imaging. The use of functional MRI and diffusion tensor imaging to map brain function and structure offers a new dimension to an understanding of the human condition. Clinical applications of functional MRI will influence many specialties including surgery, education, and rehabilitation. Functional imaging has the potential to visualize the regional concentration of specific proteins. This imaging at the level of molecules may be possible by use of a contrast material whose signal is changed by local enzymatic activity. The three-dimensional digital data collected in modern imaging techniques allow for virtual endoscopy in the respiratory, alimentary, and cardiovascular systems. Virtual endoscopy may replace many of the more invasive diagnostic methods in the near future. The measurement of clinical decision-making through observer performance studies better informs both the physician and the patient on how to improve upon the quality of clinical practice. These prospects for progress reinforce diagnostic imaging as a cornerstone in medical informatics. The history of creating images used in medicine reveals the invention of diagnostic tools which may provide new information but premature use can result in improper application of a poorly understood technology. Research into the use of new technology may be as important as the technology itself in improving the human condition.