Pathologic and molecular features of screening low-dose computed tomography (LDCT)-detected lung cancer: a baseline and 2-year repeat study

Integrative Biomarker Panel for Improved Lung Cancer Diagnosis Using Plasma microRNAs and Sputum Bacterial DNA

This study aimed to evaluate if integrating diverse molecular biomarkers in plasma and sputum could improve the diagnosis of lung cancer. The study analyzed miRNAs in plasma and bacterial DNA in sputum from 58 lung cancer patients and 62 cancer-free smokers using droplet digital PCR. The individual plasma miRNA and sputum bacterial biomarkers had sensitivities of 62-71% and specificities of 61-79% for diagnosing lung cancer. A panel of plasma miRNA or sputum bacterial biomarkers produced sensitivities of 79-85% and specificities of 74-82%. An integromic signature consisting of two miRNAs in plasma and three bacterial biomarkers in sputum had a higher sensitivity (87%) and specificity (89%) compared to individual biomarkers. The signature's diagnostic value was confirmed in a validation cohort of 56 lung cancer patients and 59 controls, independent of tumor stage, histological type, and demographic factors. Integrating diverse molecular biomarkers in plasma and sputum could improve the diagnosis of lung cancer.

Multiple primary lung cancer: Updates and perspectives

Management of multiple primary lung cancer (MPLC) remains challenging, partly due to its increasing incidence, especially with the significant rise in cases of multiple lung nodules caused by low-dose computed tomography screening. Moreover, the indefinite pathogenesis, diagnostic criteria, and treatment selection add to the complexity. In recent years, there have been continuous efforts to dissect the molecular characteristics of MPLC and explore new diagnostic approaches as well as treatment modalities, which will be reviewed here, with a focus on newly emerging evidence and future perspectives, hope to provide new insights into the management of MPLC and serve as inspiration for future research related to MPLC.

Computational Characterization of Undifferentially Expressed Genes with Altered Transcription Regulation in Lung Cancer

A transcriptome profiles the expression levels of genes in cells and has accumulated a huge amount of public data. Most of the existing biomarker-related studies investigated the differential expression of individual transcriptomic features under the assumption of inter-feature independence. Many transcriptomic features without differential expression were ignored from the biomarker lists. This study proposed a computational analysis protocol (mqTrans) to analyze transcriptomes from the view of high-dimensional inter-feature correlations. The mqTrans protocol trained a regression model to predict the expression of an mRNA feature from those of the transcription factors (TFs). The difference between the predicted and real expression of an mRNA feature in a query sample was defined as the mqTrans feature. The new mqTrans view facilitated the detection of thirteen transcriptomic features with differentially expressed mqTrans features, but without differential expression in the original transcriptomic values in three independent datasets of lung cancer. These features were called dark biomarkers because they would have been ignored in a conventional differential analysis. The detailed discussion of one dark biomarker, GBP5, and additional validation experiments suggested that the overlapping long non-coding RNAs might have contributed to this interesting phenomenon. In summary, this study aimed to find undifferentially expressed genes with significantly changed mqTrans values in lung cancer. These genes were usually ignored in most biomarker detection studies of undifferential expression. However, their differentially expressed mqTrans values in three independent datasets suggested their strong associations with lung cancer.

Lung cancer screening: who pays? Who receives? The European perspectives

Lung cancer is the leading cause of cancer-related death worldwide, and its early detection is critical to achieving a curative treatment and to reducing mortality. Low-dose computed tomography (LDCT) is a highly sensitive technique for detecting noninvasive small lung tumors in high-risk populations. We here analyze the current status of lung cancer screening (LCS) from a European point of view. With economic burden of health care in most European countries resting on the state, it is important to reduce costs of screening and improve its effectiveness. Current cost-effectiveness analyses on LCS have indicated a favorable economic profile. The most recently published analysis reported an incremental cost-effectiveness ratio (ICER) of €3,297 per 1 life-year gained adjusted for the quality of life (QALY) and €2,944 per life-year gained, demonstrating a 90% probability of ICER being below €15,000 and a 98.1% probability of being below €25,000. Different risk models have been used to identify the target population; among these, the PLCOM2012 in particular allows for the selection of the population to be screened with high sensitivity. Risk models should also be employed to define screening intervals, which can reduce the general number of LDCT scans after the baseline round. Future perspectives of screening in a European scenario are related to the will of the policy makers to implement policy on a large scale and to improve the effectiveness of a broad screening of smoking-related disease, including cardiovascular prevention, by measuring coronary calcium score on LDCT. The employment of artificial intelligence (AI) in imaging interpretation, the use of liquid biopsies for the characterization of CT-detected undetermined nodules, and less invasive, personalized surgical treatments, will improve the effectiveness of LCS.

Screen-detected multiple primary lung cancers in the ITALUNG trial

Occurrence of multiple primary lung cancers (MPLC) in individuals undergoing low-dose computed tomography (LDCT) screening has not been thoroughly addressed. We investigated MPLC in subjects recruited in the ITALUNG randomized clinical trial. Cases of cytologically/histologically proven MPLC detected at screening LDCT or follow-up CT were selected and pathologically re-evaluated according to the WHO 2015 classification. Overall 16 MPLC were diagnosed at screening LDCT (n=14, all present at baseline) or follow-up CT (n=2) in six subjects (4 in one subject, 3 in two and 2 in three subjects), representing 0.43% of the 1,406 screenees and 15.8% of the 38 subjects with at least one screen-detected primary lung cancer. MPLC included 9 adenocarcinomas in three subjects and a combination of 7 different tumour histotypes in three subjects. MPLC, mostly adenocarcinomas, are not uncommon in smokers and ex-smokers with at least one LDCT screen detected primary lung cancer.

Assessing the feasibility of confocal laser endomicroscopy in solitary pulmonary nodules for different part of the lungs, using either 0.6 or 1.4 mm probes

BACKGROUND

Malignant solitary pulmonary nodules (SPN) have become more prevalent, with upper lobes predilection. Probe-based confocal laser endomicroscopy (pCLE) provides in-vivo imaging of SPN. However, the stiffness of the 1mm confocal probe (AlveoFlex) causes difficult accessibility to the upper lobes. A thinner 600μm probe designed for bile duct exploration (CholangioFlex) has the potential to reach the upper lobes.

OBJECTIVES

To examine the accessibility of malignant SPNs in all segments of the lungs using either the 0.6mm or 1.4 mm probe and to assess the quality and inter observer interpretation of SPN confocal imaging obtained from either miniprobes.

METHODS

Radial(r)-EBUS was used to locate and sample the SPN. In-vivo pCLE analysis of the SPN was performed using either CholangioFlex (apical and posterior segments of the upper lobes) or AlveoFlex (other segments) introduced into the guide sheath before sampling. pCLE features were compared between the two probes.

RESULTS

Fourty-eight patients with malignant SPN were included (NCT01931579). The diagnostic accuracy for lung cancer using r-EBUS coupled with pCLE imaging was 79.2%. All the SPNs were successfully explored with either one of the probes (19 and 29 subjects for CholangioFlex and AlveoFlex, respectively). A specific solid pattern in the SPN was found in 30 pCLE explorations. Comparison between the two probes found no differences in the axial fibers thickness, cell size and specific solid pattern in the nodules. Extra-alveolar microvessel size appeared larger using CholangioFlex suggesting less compression effect. The kappa test for interobserver agreement for the identification of solid pattern was 0.74 (p = 0.001).

CONCLUSION

This study demonstrates that pCLE imaging of SPNs is achievable in all segments of both lungs using either the 0.6mm or 1.4mm miniprobe.

Management of pulmonary neuroendocrine tumors

Neuroendocrine tumors (NETs) of the lung are divided into 4 major types: small cell lung cancer (SCLC), large cell neuroendocrine carcinoma (LCNEC), atypical carcinoid (AC) or typical carcinoid (TC). Each classification has distinctly different treatment paradigms, making an accurate initial diagnosis essential. The inconsistent clinical presentation of this disease, however, makes this difficult. The objective of this manuscript is to detail the diagnosis and management of the well differentiated pulmonary carcinoid (PC) tumors. A multidisciplinary approach to work up and treatment should be utilized for each patient. A multimodal radiological work-up is used for diagnosis, with contrast enhanced CT predominantly utilized and functional imaging techniques. A definitive diagnosis is based on tissue findings. Surgical management remains the mainstay of therapy and can be curative. In those with advanced disease, medical treatments consist of somatostatin analog (SSA) therapy, targeted therapy, chemotherapy or peptide receptor radionuclide therapy. SSAs are the standard of care in those with metastatic NETs, using either Octreotide long acting repeatable (LAR) or lanreotide as reasonable options, despite a scarcity of prospective data in PCs. Targeted therapies consist of everolimus which is approved for use in PCs, with various studies showing mixed results with other targeted agents. Additionally, radionuclide therapy may be used and has been shown to increase survival and to reduce symptoms in some studies. Prospective trials are needed to determine other strategies that may be beneficial in PCs as well as sequencing of therapy. Successful diagnosis and optimal treatment relies on a multidisciplinary approach in patients with lung NETs. Clinical trials should be used in appropriate patients.

Current understanding and approach to well differentiated lung neuroendocrine tumors: an update on classification and management

Neuroendocrine tumors (NETs) are rare neoplasms that can arise from any tissue. They are classified based on embryonic gut derivative (i.e. foregut, midgut and hindgut) with midgut tumors being the most common (e.g. gastrointestinal NET). The second most common category of NETs is that which arises from the lung. In fact, 25% of primary lung cancers are NETs, including small cell lung cancer (SCLC), which comprises 20% of all lung cancers. The remaining 5% are large cell neuroendocrine cancer (LCNEC, 3%), typical carcinoids (TCs, 1.8%), and atypical carcinoids (ACs, 0.2%). The less common TCs/ACs are well differentiated lung NETs. Their incidence has been increasing in more recent years and although these tumors are slow growing, advanced disease is associated with poor survival. There have been advances in classification of lung NETs that have allowed for more appropriate management upfront. They are cured by surgical resection when disease is limited. However, advanced and metastatic disease requires medical therapy that is ever changing and expanding. In this review, the aim is to summarize the current understanding and classification of well differentiated lung NETs (i.e. TCs and ACs), and focus on recent updates in medical management of advanced disease, along with a brief discussion on potential future discoveries.

Can CT Screening Give Rise to a Beneficial Stage Shift in Lung Cancer Patients? Systematic Review and Meta-Analysis

OBJECTIVES

To portray the stage characteristics of lung cancers detected in CT screenings, and explore whether there's universal stage superiority over other methods for various pathological types using available data worldwide in a meta-analysis approach.

MATERIALS AND METHODS

EMBASE and MEDLINE were searched for studies on lung cancer CT screening in natural populations through July 2015 without language or other filters. Twenty-four studies (8 trials and 16 cohorts) involving 1875 CT-detected lung cancer patients were enrolled and assessed by QUADAS-2. Pathology-confirmed stage information was carefully extracted by two reviewers. Stage I or limited stage proportions were pooled by random effect model with Freeman-Tukey double arcsine transformation.

RESULTS

Pooled stage I cancer proportion in CT screenings was 73.2% (95% confidence interval: 68.6%, 77.5%), with a significant rising trend (Ptrend<0.05) from baseline (64.7%) to ≥5 repeat rounds (87.1%). Relative to chest radiograph and usual care, the increased stage I proportions in CT were 12.2% (P>0.05), and 46.5% (P<0.05), respectively. Pathology-specifically, adenocarcinomas (66%) and squamous cell lung cancers (17%) composed the majority of CT-detected lung cancers, and had significantly higher stage I proportions relative to chest radiograph (bronchioloalveolar adenocarcinomas, 80.9% vs 51.4%; other adenocarcinomas, 58.8% vs 38.3%; squamous cell lung cancers, 52.3% vs 38.3%; all P<0.05). However, the percentage of small cell lung cancer was lower using CT than other detection routes, and no significant difference in limited stage proportion was observed (6.8% vs 10.8%, P>0.05).

CONCLUSION

CT screening can detect more early stage non-small cell lung cancers, but not all of them could be beneficial as there are a considerable number of indolent ones such as bronchioloalveolar adenocarcinomas. Still, current evidence is lacking regarding small cell lung cancers.

Molecular profile of liquid biopsies: next generation biomarkers to improve lung cancer treatment

Molecular profiling of liquid biopsies is now emerging as pivotal for cancer biomarker discovery. The low-invasive nature of the approach used for collecting biospecimens (i.e. blood, urine, saliva, etc.) may allow a widespread application of novel molecular diagnostics based on liquid biopsies. This is relevant, for example, in cancer screening programmes where it is essential to reduce costs and the complexity of screening tests in order to increase study compliance and effectiveness. Here, I discuss recent advances in biomarkers for the early cancer detection and prediction of chemotherapy response based on the molecular profiling of liquid biopsies.

Pulmonary neuroendocrine (carcinoid) tumors: European Neuroendocrine Tumor Society expert consensus and recommendations for best practice for typical and atypical pulmonary carcinoids

BACKGROUND

Pulmonary carcinoids (PCs) are rare tumors. As there is a paucity of randomized studies, this expert consensus document represents an initiative by the European Neuroendocrine Tumor Society to provide guidance on their management.

PATIENTS AND METHODS

Bibliographical searches were carried out in PubMed for the terms 'pulmonary neuroendocrine tumors', 'bronchial neuroendocrine tumors', 'bronchial carcinoid tumors', 'pulmonary carcinoid', 'pulmonary typical/atypical carcinoid', and 'pulmonary carcinoid and diagnosis/treatment/epidemiology/prognosis'. A systematic review of the relevant literature was carried out, followed by expert review.

RESULTS

PCs are well-differentiated neuroendocrine tumors and include low- and intermediate-grade malignant tumors, i.e. typical (TC) and atypical carcinoid (AC), respectively. Contrast CT scan is the diagnostic gold standard for PCs, but pathology examination is mandatory for their correct classification. Somatostatin receptor imaging may visualize nearly 80% of the primary tumors and is most sensitive for metastatic disease. Plasma chromogranin A can be increased in PCs. Surgery is the treatment of choice for PCs with the aim of removing the tumor and preserving as much lung tissue as possible. Resection of metastases should be considered whenever possible with curative intent. Somatostatin analogs are the first-line treatment of carcinoid syndrome and may be considered as first-line systemic antiproliferative treatment in unresectable PCs, particularly of low-grade TC and AC. Locoregional or radiotargeted therapies should be considered for metastatic disease. Systemic chemotherapy is used for progressive PCs, although cytotoxic regimens have demonstrated limited effects with etoposide and platinum combination the most commonly used, however, temozolomide has shown most clinical benefit.

CONCLUSIONS

PCs are complex tumors which require a multidisciplinary approach and long-term follow-up.

Whole exome sequencing identifies driver mutations in asymptomatic computed tomography-detected lung cancers with normal karyotype

The efficacy of curative surgery for lung cancer could be largely improved by non-invasive screening programs, which can detect the disease at early stages. We previously showed that 18% of screening-identified lung cancers demonstrate a normal karyotype and, following high-density genome scanning, can be subdivided into samples with 1) numerous; 2) none; and 3) few copy number alterations. Whole exome sequencing was applied to the two normal karyotype, screening-detected lung cancers, constituting group 2, as well as normal controls. We identified mutations in both tumors, including KEAP1 (commonly mutated in lung cancers) in one, and TP53, PMS1, and MSH3 (well-characterized DNA-repair genes) in the other. The two normal karyotype screening-detected lung tumors displayed a typical lung cancer mutational profile that only next generation sequencing could reveal, which offered an additional contribution to the over-diagnosis bias concept hypothesized within lung cancer screening programs.

International association for the study of lung cancer/american thoracic society/european respiratory society international multidisciplinary classification of lung adenocarcinoma

INTRODUCTION

Adenocarcinoma is the most common histologic type of lung cancer. To address advances in oncology, molecular biology, pathology, radiology, and surgery of lung adenocarcinoma, an international multidisciplinary classification was sponsored by the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society. This new adenocarcinoma classification is needed to provide uniform terminology and diagnostic criteria, especially for bronchioloalveolar carcinoma (BAC), the overall approach to small nonresection cancer specimens, and for multidisciplinary strategic management of tissue for molecular and immunohistochemical studies.

METHODS

An international core panel of experts representing all three societies was formed with oncologists/pulmonologists, pathologists, radiologists, molecular biologists, and thoracic surgeons. A systematic review was performed under the guidance of the American Thoracic Society Documents Development and Implementation Committee. The search strategy identified 11,368 citations of which 312 articles met specified eligibility criteria and were retrieved for full text review. A series of meetings were held to discuss the development of the new classification, to develop the recommendations, and to write the current document. Recommendations for key questions were graded by strength and quality of the evidence according to the Grades of Recommendation, Assessment, Development, and Evaluation approach.

RESULTS

The classification addresses both resection specimens, and small biopsies and cytology. The terms BAC and mixed subtype adenocarcinoma are no longer used. For resection specimens, new concepts are introduced such as adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) for small solitary adenocarcinomas with either pure lepidic growth (AIS) or predominant lepidic growth with ≤ 5 mm invasion (MIA) to define patients who, if they undergo complete resection, will have 100% or near 100% disease-specific survival, respectively. AIS and MIA are usually nonmucinous but rarely may be mucinous. Invasive adenocarcinomas are classified by predominant pattern after using comprehensive histologic subtyping with lepidic (formerly most mixed subtype tumors with nonmucinous BAC), acinar, papillary, and solid patterns; micropapillary is added as a new histologic subtype. Variants include invasive mucinous adenocarcinoma (formerly mucinous BAC), colloid, fetal, and enteric adenocarcinoma. This classification provides guidance for small biopsies and cytology specimens, as approximately 70% of lung cancers are diagnosed in such samples. Non-small cell lung carcinomas (NSCLCs), in patients with advanced-stage disease, are to be classified into more specific types such as adenocarcinoma or squamous cell carcinoma, whenever possible for several reasons: (1) adenocarcinoma or NSCLC not otherwise specified should be tested for epidermal growth factor receptor (EGFR) mutations as the presence of these mutations is predictive of responsiveness to EGFR tyrosine kinase inhibitors, (2) adenocarcinoma histology is a strong predictor for improved outcome with pemetrexed therapy compared with squamous cell carcinoma, and (3) potential life-threatening hemorrhage may occur in patients with squamous cell carcinoma who receive bevacizumab. If the tumor cannot be classified based on light microscopy alone, special studies such as immunohistochemistry and/or mucin stains should be applied to classify the tumor further. Use of the term NSCLC not otherwise specified should be minimized.

CONCLUSIONS

This new classification strategy is based on a multidisciplinary approach to diagnosis of lung adenocarcinoma that incorporates clinical, molecular, radiologic, and surgical issues, but it is primarily based on histology. This classification is intended to support clinical practice, and research investigation and clinical trials. As EGFR mutation is a validated predictive marker for response and progression-free survival with EGFR tyrosine kinase inhibitors in advanced lung adenocarcinoma, we recommend that patients with advanced adenocarcinomas be tested for EGFR mutation. This has implications for strategic management of tissue, particularly for small biopsies and cytology samples, to maximize high-quality tissue available for molecular studies. Potential impact for tumor, node, and metastasis staging include adjustment of the size T factor according to only the invasive component (1) pathologically in invasive tumors with lepidic areas or (2) radiologically by measuring the solid component of part-solid nodules.

Budesonide versus placebo in high-risk population with screen-detected lung nodules: rationale, design and methodology

BACKGROUND

Screening-CT is able to discover small peripheral lung nodules. The nature of these nodules is uncertain but it is reasonable that some of them, in particular the non-solid ones, could represent precancerous lesions. A previous trial showed a reduction in size of peripheral nodules by inhaled budesonide in subjects with bronchial dysplasia.

OBJECTIVE

The primary objective of the study was the evaluation of the effect of budesonide as a chemopreventive agent for lung lesions. The primary endpoint was the modification of lung lesions at ld-CT scan (according to RECIST criteria) after one year of treatment in a person-specific analysis.

METHODS

We performed a randomized, double-blind, placebo controlled trial to evaluate whether inhaled budesonide was able to reduce size and number of persistent, undetermined CT-detected lung nodules in high-risk asymptomatic subjects currently undergoing a five-year CT scan screening program at the European Institute of Oncology.

RESULTS

Trial enrollment started in April 2006 and ended in July 2007 with the randomization of 202 current or former smokers with stable CT-detected lung nodules set to receive budesonide 800 μg or placebo twice daily for 12 months.

CONCLUSION

Our trial represents the first phase II study of a chemopreventive intervention focusing on the peripheral lung, where the majority of lung cancers arise. The research was nested into a screening project with clear advantages in participant accrual and reduction of costs. This paper describes the rationale and design of the study, thus focusing on the methodology and operational aspects of the clinical trial. (Clinicaltrials.gov number. NCT00321893).

Genomic characterization of asymptomatic CT-detected lung cancers

Computed tomography (CT) screening of lung cancer allows the detection of early tumors. The objective of our study was to verify whether initial asymptomatic lung cancers, identified by high-resolution low-dose CT (LD-CT) on a high-risk population, show genetic abnormalities that could be indicative of the early events of lung carcinogenesis. We analyzed 78 tumor samples: 21 (pilot population) from heavy smokers with asymptomatic non-screening detected early-stage lung cancers and 57 from 5203 asymptomatic heavy smoker volunteers, who underwent a LD-CT screening study. During surgical resection of the detected tumors, tissue samples were collected and short-term cultures were started for karyotype evaluation. Samples were classified according to the normal (NK) or aneuploid (AK) karyotype. The NK samples were further analyzed by the Affymetrix single-nucleotide polymorphisms (SNPs) technology. Metaphase spreads were obtained in 73.0% of the selected samples: 80.7% showed an AK. A statistically significant correlation was found between presence of vascular invasion and abnormal karyotype. A total of 10 NK samples were suitable for SNPs analysis. Subtle genomic alterations were found in eight tumors, the remaining two showing no evidence to date of chromosomal aberrations anywhere in the genome. Two common regions of amplification were identified at 5p and 8p11. Mutation analysis by direct sequencing was conducted for the K-RAS, TP53 and EGFR genes, confirming data already described for heavy smokers. We show that: (i) the majority of screening-detected tumors are aneuploid; (ii) early-stage tumors tend to harbor a less abnormal karyotype; (iii) whole genome analysis of NK tumors allows for the detection of common regions of copy number variation (such as amplifications at 5p and 8p11), highlighting genes that might be considered candidate markers of early events in lung carcinogenesis.

Long-term outcomes of a pilot CT screening for lung cancer

BACKGROUND

Low-dose computed tomography (CT) screening can detect early stage lung cancer in high-risk populations. However, no data on repeated annual screening over more than 5 years are available, and the impact of screening on lung cancer mortality is controversial.

METHODS

We analysed outcomes in high-risk asymptomatic volunteers (smokers and former smokers, >50 years) enrolled in a pilot study over 1 year from June 2000, who received annual low-dose CT for 7 years. Cumulative lung cancer incidence and survival were represented by Kaplan-Meier curves. Standardized incidence and mortality ratios were used to estimate risks relative to the general Italian and US population.

RESULTS

Compliance was 86% at the end of the seventh year in 1035 recruited volunteers (71% men, mean age 58 years). Lung cancer was diagnosed in 54 (5.3%); radical surgery was possible in 48/54 (87%); 39/54 (72%) had stage I disease. Five-year survival was 63% overall, 89% for stage I cases. During 6308 person-years of observation, 47 participants had died versus 75 expected in the Italian general population standardised for age and sex. Fourteen lung cancer deaths were registered versus 27 expected in a standardised US smoker population.

CONCLUSIONS

Seventy percent of screening-diagnosed patients had stage I disease, and the survival of screen-detected cancer patients was high. Lung cancer mortality was favourable compared to age- and sex-matched population of US smokers, suggesting that mortality can be lowered by screening, although larger trials with longer follow-up are necessary to confirm these findings.

The Classification of Lung Carcinoma: Time to Change the Morphology-Based Approach?

Morphology still remains the cornerstone in lung cancer classification and always has been accompanying pathologists in their daily activity, even though several ancillary techniques have been incorporated over time to improve diagnostic, prognostic, and predictive capabilities in lung cancer. Currently, we are also faced with a global rethinking of lung cancer care, especially once novel therapy strategies have been made available on the basis of the diverse characteristics of tumors. Although morphology still remains a not easily replaceable tool for lung cancer classification, we are now challenged by the need of offering clinicians more detailed subtyping of non-small-cell lung cancer especially in event of limited diagnostic material, poorly differentiated tumors, or unresectable lesions. Close integration of improved morphology, immunohistochemistry, and molecular tests will be able to not only sharpen our diagnostic algorithms and prognostic and predictive potentialities but also get insights into several lung cancer biology issues, such as histogenesis and new classification schemes.

High-resolution computed tomography screening for lung cancer: unexpected findings and new controversies regarding adenocarcinogenesis

CONTEXT

Recent advances in human imaging technologies reawakened interest in lung cancer screening. Although historic and current preliminary and noncontrolled studies have not shown a decrease in lung cancer mortality in screened populations, many explanations have been proffered while the lung cancer community awaits the results of several large controlled population studies.

OBJECTIVE

To critically review the current model of adenocarcinoma development against the background of lung cancer screening results combined with observational pathologic and radiographic studies.

DATA SOURCES

Published articles pertaining to lung cancer screening, lung adenocarcinoma pathology, and radiology accessible through PubMed form the basis for this review.

CONCLUSIONS

The current adenocarcinogenesis model is probably valid for many but not all lung adenocarcinomas. Screening data combined with radiographic and pathologic studies suggest that not all lung adenocarcinomas are clinically aggressive, and it is uncertain whether all aggressive adenocarcinomas arise from identified precursors.

Lung cancer screening update

Low-dose computed tomography (ld-CT) for lung cancer screening in high-risk subjects is performed within clinical trials and has started to be used in routine clinical practice. The technique is well defined, even if some methodological problems are still debated, such as the measurements of pulmonary nodules, the size to define them as clinically significant, the management of small or non-solid nodules and the best diagnostic work-up to optimize diagnostic accuracy. The data derived from an IEO observational study, started in 2000, shows a high prevalence and incidence of early stage lung cancer detected at ld-CT, demonstrating the need to prolong observation for a long period of time. The high survival rate of patients with screening-detected cancer has recently been debated in a number of papers using statistical models, but the advantage of the yearly ld-CT for the individuals is unquestionable; its benefit on the population base has still to be demonstrated by ongoing randomized trials.

Review article: pulmonary sarcomatoid carcinomas: a practical overview

Pulmonary sarcomatoid carcinomas (PSCs) are currently defined as poorly differentiated non-small-cell carcinomas containing a component with sarcoma or sarcoma-like (spindle and/or giant cell) features. They consist of 5 major histological variants, namely pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, carcinosarcoma, and pulmonary blastoma. The segregation of PSCs into a distinct clinicopathologic entity seems justified on the basis of morphologic, behavioral, and genotypic/phenotypic attributes. As a group, PSCs generally run an aggressive clinical course and may cause major difficulties in the differential diagnosis with other primary and secondary malignancies of the lung. At present, PSCs are believed to represent a family of carcinomas "in transition," in which diverse pathways of clonal evolution account for histological differences of a common ancestor lesion. The sarcomatous or sarcomatoid component of these tumors is thought to derive from carcinoma cells during the progression of carcinogenesis through the activation of an epithelial-mesenchymal transition program leading to sarcomatous transformation or metaplasia (conversion paradigm). Conceivably, targeting the epithelial-mesenchymal transition program could become a valid therapeutic strategy for these life-threatening tumors, whose sensitivity to current medical manipulation is disappointing.