Bronchioloalveolar carcinoma: a review of current concepts and evolving issues

Systemic immune-inflammation index predicts survival in patients with resected lung invasive mucinous adenocarcinoma

BACKGROUND

The prognostic-related factors of lung invasive mucinous adenocarcinoma(IMA) are unclear because of its rarity. Various inflammation-based biomarkers were reported to predict the survival of malignant diseases. This study aims to explore the prognostic significance of the systemic immune-inflammation index(SII), which is calculated using absolute platelet, neutrophil, and lymphocyte counts, among patients with invasive mucinous adenocarcinoma.

METHODS

From January 2015 to December 2019, 106 patients were identified as having IMA accepted radical resection and enrolled in the retrospective study. We analyzed the overall survival and disease-free survival using the Kaplan-Meier method and log-rank test. Receiver operating characteristic curve was used to find the optimal SII cut-off values for survival. A Cox regression model was carried out for multivariable analyses.

RESULTS

The study cohort included 53 men and 53 women, with a mean age of 60 years (range 29 to 78 years, median 61 years). The median SII measured before surgery was 378.47 (range: 79.87-1701.97). ROC analyses revealed that the optimal cut-off values of SII was 379.43 for predicting both OS and DFS. An elevated SII (≥379.43) was observed in 52 patients (49.1 %), and was associated with younger age (P = 0.02), advanced T staging (P = 0.042), lymph node metastasis (P = 0.018) and pneumonic-type IMA (P = 0.018). Multivariable analysis showed that SII and pneumonic-type IMA were independent prognostic predictors of OS and DFS in radically resected IMA patients (P < 0.05).

CONCLUSION

High SII is correlated with worse outcome and can be a novel prognostic biomarker for IMA patients accepted radical surgery.

Microfluidic chips: recent advances, critical strategies in design, applications and future perspectives

Microfluidic chip technology is an emerging tool in the field of biomedical application. Microfluidic chip includes a set of groves or microchannels that are engraved on different materials (glass, silicon, or polymers such as polydimethylsiloxane or PDMS, polymethylmethacrylate or PMMA). The microchannels forming the microfluidic chip are interconnected with each other for desired results. This organization of microchannels trapped into the microfluidic chip is associated with the outside by inputs and outputs penetrating through the chip, as an interface between the macro- and miniature world. With the help of a pump and a chip, microfluidic chip helps to determine the behavioral change of the microfluids. Inside the chip, there are microfluidic channels that permit the processing of the fluid, for example, blending and physicochemical responses. Microfluidic chip has numerous points of interest including lesser time and reagent utilization and alongside this, it can execute numerous activities simultaneously. The miniatured size of the chip fastens the reaction as the surface area increases. It is utilized in different biomedical applications such as food safety sensing, peptide analysis, tissue engineering, medical diagnosis, DNA purification, PCR activity, pregnancy, and glucose estimation. In the present study, the design of various microfluidic chips has been discussed along with their biomedical applications.

Diagnosis-to-surgery interval and survival for different histologies of stage I-IIA lung cancer

Background

Guidelines on timeliness of lung cancer surgery are inconsistent. Lung cancer histologic subtypes have different prognosis and treatment. It is important to understand the consequences of delayed surgery for each lung cancer histologic subtype. This study aimed to examine the association between diagnosis-to-surgery time interval and survival for early stage lung cancer and selected histologic subtypes.

Methods

Patients diagnosed with stage I–IIA lung cancer between 2004 and 2015 receiving definitive surgery and being followed up until Dec. 31, 2018, were identified from Surveillance, Epidemiology, and End Results database. Histologic subtypes included adenocarcinoma, squamous or epidermoid carcinoma, bronchioloalveolar carcinoma, large cell carcinoma, adenosquamous carcinoma, carcinoid carcinoma, and small cell carcinoma. Diagnosis-to-surgery interval was treated as multi-categorical variables (<1, 1–2, 2–3, and ≥3 months) and binary variables (≥1 vs. <1 month, ≥2 vs. <2 months, and ≥3 vs. <3 months). Outcomes included cancer-specific and overall survival. Covariates included age at diagnosis, sex, race, marital status, tumor size, grade, surgery type, chemotherapy, radiotherapy, and study period. Kaplan-Meier survival curves and Cox proportional hazards regression models were applied to examine the survival differences.

Results

With a median follow-up time of 51 months, a total of 40,612 patients were analyzed, including 40.1% adenocarcinoma and 24.5% squamous or epidermoid carcinoma. The proportion of patients receiving surgery <1, 1–2, 2–3, and ≥3 months from diagnosis were 34.2%, 33.9%, 19.8%, and 12.1%, respectively. Delayed surgery was associated with worse cancer-specific and overall survival for all lung cancers, adenocarcinoma, squamous or epidermoid, bronchioloalveolar, and large cell carcinoma (20–40% increased risk). Dose-dependent effects (longer delay, worse survival) were observed in all lung cancers, adenocarcinoma, and squamous and epidermoid carcinoma. No significant association between surgery delay and survival was observed in adenosquamous, carcinoid, and small cell carcinoma.

Conclusions

Our findings support the guidelines of undertaking surgery within 1 month from diagnosis in patients with stage I–IIA lung cancer. The observed dose-dependent effects emphasize the clinical importance of early surgery. Future studies with larger sample size of less frequent histologic subtypes are warranted to provide more evidence for histology-specific lung cancer treatment guidelines.

Spread through air spaces (STAS) in invasive mucinous adenocarcinoma of the lung: Incidence, prognostic impact, and prediction based on clinicoradiologic factors

Background

Spread through air spaces (STAS) has recently been demonstrated to exhibit a negative impact on lung adenocarcinoma prognosis. However, most of these studies investigated STAS in nonmucinous adenocarcinoma. Here, we investigated the incidence of STAS in invasive mucinous adenocarcinoma (IMA) of the lung and evaluated whether tumor STAS was a risk factor of disease recurrence in IMA. We also examined clinicoradiologic factors in patients with IMA harboring STAS.

Methods

We reviewed pathologic specimens and imaging characteristics of primary tumors from 132 consecutive patients who underwent surgical resection for IMA to evaluate STAS. Patients with and without STAS were compared with respect to clinical characteristics as well as computed tomography (CT) imaging using logistic regression. The relationships between all variables including STAS and survival were analyzed.

Results

Among a total of 132 patients, full pathologic specimens were available for 119 patients, and STAS was observed in 86 (72.3%). IMA patients with STAS were significantly associated with older age, presence of lobulated and spiculated margins on CT scan (P = 0.009, P = 0.006, and P = 0.027). In multivariate analysis for overall survival (OS), STAS was a borderline independent poor prognostic predictor (P = 0.028). Older age, history of smoking, higher T stage, presence of lymph node metastasis, and consolidative morphologic type remained independent predictors for OS.

Conclusions

STAS was associated with reduced OS and was a borderline independent poor prognostic factor in IMA. IMA with STAS was associated with older age and presence of lobulated and spiculated margins on CT scan.

Key points

Significant findings of the study

Compared with other subtypes, IMA shows a higher incidence of STAS, which is an independent poor prognostic predictor even in IMA. Lobulated and spiculated margins on CT are associated with STAS.

What this study adds

Considering that STAS can carry the potential for aerogenous metastasis, predicting STAS using preoperative surrogate CT imaging is desirable to avoid limited resection.

Differences in PET/CT standardized uptake values involvement and survival compared to histologic subtypes of lung adenocarcinoma

PURPOSE

Lung adenocarcinoma is histologically diverse but has distinct histologic growth patterns. There is no consensus on the clinical benefit of this histologic model. We aimed to evaluate the differences in the distribution of the preoperative primary tumor positron emission tomography (PET)/computed tomography (CT) standardized uptake values (SUVs) and survival in the lung adenocarcinoma subtypes.

METHODS

We retrospectively evaluated the data of 107 patients with resected lung adenocarcinoma who had preoperative PET/CT between 2005 and 2017 in a single center. Patients had lepidic, acinar, papillary, micropapillary, and solid histologic subtypes. We compared fluorodeoxyglucose SUVs and survival data of histologic subtypes.

RESULTS

The median age of the patients was 62 years (40-75), 76.4% were male, the median SUVmax was 9.4 (1-36.7), and the median follow-up time was 29 months (3-135 months). The median overall survival (OS) was 71 months and the median progression-free survival (PFS) was 33 months. SUVmax was significantly different in histologic subtypes: values for papillary, micropapillary, solid, acinar, and lepidic subtypes were 9.7, 8, 12, 9.1, and 3.9, respectively (p = 0.000). Solid predominant adenocarcinoma had significantly higher SUVmax than the other subtypes (p = 0.001). Lepidic predominant adenocarcinoma had significantly lower SUVmax than the other subtypes (p = 0.000). There was no significant difference in OS between histologic subtypes (p = 0.66), but PFS was significantly different between the groups (p = 0.017), and the solid subtype had a shorter PFS than the other histologic subtypes.

CONCLUSION

Lung adenocarcinoma consists of a diverse group of diseases. Different SUVmax values are seen in different histologic subtypes of nonmetastatic lung adenocarcinoma. Solid predominant types have high SUVmax values while lepidic predominant types have lower SUVmax values. The solid subtype had a shorter PFS than the other histologic subtypes.

Upcoming Revolutionary Paths in Preclinical Modeling of Pancreatic Adenocarcinoma

To date, PDAC remains the cancer having the worst prognosis with mortality rates constantly on the rise. Efficient cures are still absent, despite all attempts to understand the aggressive physiopathology underlying this disease. A major stumbling block is the outdated preclinical modeling strategies applied in assessing effectiveness of novel anticancer therapeutics. Current in vitro preclinical models have a low fidelity to mimic the exact architectural and functional complexity of PDAC tumor found in human set, due to the lack of major components such as immune system and tumor microenvironment with its associated chemical and mechanical signals. The existing PDAC preclinical platforms are still far from being reliable and trustworthy to guarantee the success of a drug in clinical trials. Therefore, there is an urgent demand to innovate novel in vitro preclinical models that mirrors with precision tumor-microenvironment interface, pressure of immune system, and molecular and morphological aspects of the PDAC normally experienced within the living organ. This review outlines the traditional preclinical models of PDAC namely 2D cell lines, genetically engineered mice, and xenografts, and describing the present famous approach of 3D organoids. We offer a detailed narration of the pros and cons of each model system. Finally, we suggest the incorporation of two off-center newly born techniques named 3D bio-printing and organs-on-chip and discuss the potentials of swine models and in silico tools, as powerful new tools able to transform PDAC preclinical modeling to a whole new level and open new gates in personalized medicine.

Lung-on-a-chip: the future of respiratory disease models and pharmacological studies

Recently, organ-on-a-chip models, which are microfluidic devices that mimic the cellular architecture and physiological environment of an organ, have been developed and extensively investigated. The chips can be tailored to accommodate the disease conditions pertaining to many organs; and in the case of this review, the lung. Lung-on-a-chip models result in a more accurate reflection compared to conventional in vitro models. Pharmaceutical drug testing methods traditionally use animal models in order to evaluate pharmacological and toxicological responses to a new agent. However, these responses do not directly reflect human physiological responses. In this review, current and future applications of the lung-on-a-chip in the respiratory system will be discussed. Furthermore, the limitations of current conventional in vitro models used for respiratory disease modeling and drug development will be addressed. Highlights of additional translational aspects of the lung-on-a-chip will be discussed in order to demonstrate the importance of this subject for medical research.

Modelling cancer in microfluidic human organs-on-chips

One of the problems that has slowed the development and approval of new anticancer therapies is the lack of preclinical models that can be used to identify key molecular, cellular and biophysical features of human cancer progression. This is because most in vitro cancer models fail to faithfully recapitulate the local tissue and organ microenvironment in which tumours form, which substantially contributes to the complex pathophysiology of the disease. More complex in vitro cancer models have been developed, including transwell cell cultures, spheroids and organoids grown within flexible extracellular matrix gels, which better mimic normal and cancerous tissue development than cells maintained on conventional 2D substrates. But these models still lack the tissue-tissue interfaces, organ-level structures, fluid flows and mechanical cues that cells experience within living organs, and furthermore, it is difficult to collect samples from the different tissue microcompartments. In this Review, we outline how recent developments in microfluidic cell culture technology have led to the generation of human organs-on-chips (also known as organ chips) that are now being used to model cancer cell behaviour within human-relevant tissue and organ microenvironments in vitro. Organ chips enable experimentalists to vary local cellular, molecular, chemical and biophysical parameters in a controlled manner, both individually and in precise combinations, while analysing how they contribute to human cancer formation and progression and responses to therapy. We also discuss the challenges that must be overcome to ensure that organ chip models meet the needs of cancer researchers, drug developers and clinicians interested in personalized medicine.

Serum proteome mapping of EGF transgenic mice reveal mechanistic biomarkers of lung cancer precursor lesions with clinical significance for human adenocarcinomas

Atypical adenomatous hyperplasia (AAH) of the lung is a pre-invasive lesion (PL) with high risk of progression to lung cancer (LC). However, the pathways involved are uncertain. We searched for novel mechanistic biomarkers of AAH in an EGF transgenic disease model of lung cancer. Disease regulated proteins were validated by Western immunoblotting and immunohistochemistry (IHC) of control and morphologically altered respiratory epithelium. Translational work involved clinical resection material. Collectively, 68 unique serum proteins were identified by 2DE-MALDI-TOF mass spectrometry and 13 reached statistical significance (p < 0.05). EGF, amphiregulin and the EGFR endosomal sorting protein VPS28 were induced up to 5-fold while IHC confirmed strong induction of these proteins. Furthermore, ApoA1, α-2-macroglobulin, and vitamin-D binding protein were nearly 6- and 2-fold upregulated in AAH; however, ApoA1 was oppositely regulated in LC to evidence disease stage dependent regulation of this tumour suppressor. Conversely, plasminogen and transthyretin were highly significantly repressed by 3- and 20-fold. IHC confirmed induced ApoA1, Fetuin-B and transthyretin expression to influence calcification, inflammation and tumour-infiltrating macrophages. Moreover, serum ApoA4, ApoH and ApoM were 2-, 2- and 6-fold repressed; however tissue ApoM and sphingosine-1-phosphate receptor expression was markedly induced to suggest a critical role of sphingosine-1-phosphate signalling in PL and malignant transformation. Finally, a comparison of three different LC models revealed common and unique serum biomarkers mechanistically linked to EGFR, cMyc and cRaf signalling. Their validation by IHC on clinical resection material established relevance for distinct human lung pathologies. In conclusion, we identified mechanistic biomarker candidates recommended for in-depth clinical evaluation.

Human Organ Chip Models Recapitulate Orthotopic Lung Cancer Growth, Therapeutic Responses, and Tumor Dormancy In Vitro

Here, we show that microfluidic organ-on-a-chip (organ chip) cell culture technology can be used to create in vitro human orthotopic models of non-small-cell lung cancer (NSCLC) that recapitulate organ microenvironment-specific cancer growth, tumor dormancy, and responses to tyrosine kinase inhibitor (TKI) therapy observed in human patients in vivo. Use of the mechanical actuation functionalities of this technology revealed a previously unknown sensitivity of lung cancer cell growth, invasion, and TKI therapeutic responses to physical cues associated with breathing motions, which appear to be mediated by changes in signaling through epidermal growth factor receptor (EGFR) and MET protein kinase. These findings might help to explain the high level of resistance to therapy in cancer patients with minimal residual disease in regions of the lung that remain functionally aerated and mobile, in addition to providing an experimental model to study cancer persister cells and mechanisms of tumor dormancy in vitro.

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.

Understanding Idiopathic Interstitial Pneumonia: A Gene-Based Review of Stressed Lungs

Pulmonary fibrosis is the main cause of severe morbidity and mortality in idiopathic interstitial pneumonias (IIP). In the past years, there has been major progress in the discovery of genetic factors that contribute to disease. Genes with highly penetrant mutations or strongly predisposing common risk alleles have been identified in familial and sporadic IIP. This review summarizes genes harbouring causative rare mutations and replicated common predisposing alleles. To date, rare mutations in nine different genes and five risk alleles fulfil this criterion. Mutated genes represent three genes involved in surfactant homeostasis and six genes involved in telomere maintenance. We summarize gene function, gene expressing cells, and pathological consequences of genetic alterations associated with disease. Consequences of the genetic alteration include dysfunctional surfactant processing, ER stress, immune dysregulation, and maintenance of telomere length. Biological evidence shows that these processes point towards a central role for alveolar epithelial type II cell dysfunction. However, tabulation also shows that function and consequence of most common risk alleles are not known. Most importantly, the predisposition of the MUC5B risk allele to disease is not understood. We propose a mechanism whereby MUC5B decreases surface tension lowering capacity of alveolar surfactant at areas with maximal mechanical stress.

Relation between thin-section computed tomography and clinical findings of mucinous adenocarcinoma

BACKGROUND

Detailed reports on mucinous adenocarcinoma (formerly "mucinous bronchioloalveolar carcinoma") have not been published. We evaluated the correlation between thin-section computed tomography findings and the clinicopathologic characteristics and prognosis of mucinous adenocarcinoma.

METHODS

From April 1997 to March 2008, 45 resected lung carcinomas were diagnosed as mucinous adenocarcinoma. Five cases of multiple lung cancers or ambiguous mucinous adenocarcinoma were excluded. Tumors were classified as "solitary-type" or "pneumonic-type" tumors according to the thin-section computed tomography findings. We evaluated the clinicopathologic characteristics and the epidermal growth factor receptor and KRAS gene mutation statuses and correlated the thin-section computed tomography findings with patient prognoses.

RESULTS

Thirty patients had solitary-type and 10 had pneumonic-type tumors. The lesions in 23, 14, and 3 patients were classified as pathologic stage I, stage II, and stage III, respectively. Five patients had adenocarcinoma in situ, 9 had minimally invasive adenocarcinoma, and 26 had invasive mucinous adenocarcinoma. Thirteen patients showed recurrences, which were classified as intrapulmonary metastases in all patients. The 5-year overall and relapse-free survival rates were 83.3% and 88.8%, respectively, in patients with solitary-type tumors and 20.0% and 0%, respectively, in patients with pneumonic-type tumors (p < 0.001). The median follow-up time for surviving patients was 81 months. KRAS mutations were detected in 30 patients, but epidermal growth factor receptor mutations were absent in all patients.

CONCLUSIONS

Our results indicated that thin-section computed tomography findings for mucinous adenocarcinoma were useful in predicting prognosis before surgical resection. Further studies are required to improve the treatment strategy for mucinous adenocarcinoma.

The 2011 IASLC/ATS/ERS pulmonary adenocarcinoma classification: a landmark in personalized medicine for lung cancer management

In 2011, three authoritative academic communities, International Association for the Study of Lung Cancer, the American Thoracic Society, and the European Respiratory Society (IASLC/ATS/ERS), published a novel lung adenocarcinoma histologic classification. The major modifications of this classification include the abolishment of the term "bronchioloalveolar carcinoma (BAC)", the establishment of new classification systems for resection and small biopsy or cytology specimens, the emphasis of molecular test and comprehensive histologic evaluation for tumor specimens, etc. This new lung adenocarcinoma classification signifies the era of personalized medicine comes to real-world practice in lung cancer field. Here, we introduce the background why the lung adenocarcinoma classification needs to be revised, and what we should consider in clinical practice according to this new classification.

Updating the 2011 International Association for the Study of Lung Cancer classification of lung adenocarcinoma: main priorities and implications for clinicians

SUMMARY: 

The classification of adenocarcinoma was revised by the International Association for the Study of Lung Cancer, the American Thoracic Society and the European Respiratory Society in 2011. In the face of advances of medical therapy in advanced stage disease, these groups sought to improve prognostication and to standardize reporting protocols. A discussion of recent alterations in terminology is undertaken. Included with this is clarification of terminology used small biopsy and cytology specimens. In addition, it will be discussed how an architectural-based classification can be used to assess prognosis and how this applies staging and potential patient management. Several studies have confirmed the effectiveness and reproducibility of the 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification on lung adenocarcinoma. In addition, there is increasing evidence of clinical application in early stage lung adenocarcinoma. While there may be potential revision in the future, the classification provides better and more standardized information for both clinicians and researchers.

Clinical importance of [18F]fluorodeoxyglucose positron emission tomography/computed tomography in the management of patients with bronchoalveolar carcinoma: Role in the detection of recurrence

[¹⁸F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) has been reported to have a low sensitivity in the initial diagnosis of bronchoalveolar carcinoma (BAC) due to BAC’s low metabolic activity. The aim of this study was to assess the value of [¹⁸F]FDG-PET/CT in the detection of BAC recurrence. Between February 2007 and September 2011, the [¹⁸F]FDG-PET/CT scans that were performed on patients with known, histologically proven BAC were studied. A total of 24 [¹⁸F]FDG-PET/CT scans were performed in 22 patients, including 16 males and 6 females, with a mean age of 65±9 years. Among the scans, 15 were performed to assess for possible recurrence with equivocal findings in conventional imaging methods and 9 for restaging post-therapy. In all cases conventional imaging studies (CT and MRI) were performed 5–30 days prior to PET/CT. Among the 24 [¹⁸F]FDG-PET/CT scans, 18 were positive and 6 negative. Among the 15 [¹⁸F]FDG-PET/CT scans performed for suspected recurrence, 34 lesions were detected and the mean maximum standardized uptake value (SUVmax) was 6.8±3.26. In nine scans, upstaging was observed, while two were in agreement with the findings of the conventional modalities. A greater number of lesions were detected in two scans and fewer lesions were detected in one, with no change in staging. Only one scan was negative. By contrast, in patients examined for restaging, there were only five lesions with a mean SUVmax of 4.86±3.18. Agreement between the findings of [¹⁸F]FDG-PET/CT and the conventional modalities was observed in 8 out of 9 cases. Although [¹⁸F]FDG-PET/CT has been reported to have a low sensitivity in the initial diagnosis of BAC, the present results indicate that when there is recurrence, the lesions become [¹⁸F]FDG avid. [¹⁸F]FDG-PET/CT may provide further information in patients evaluated for recurrence and thus improve patient management.

Relationship between lung adenocarcinoma histological subtype and patient prognosis

PURPOSE

Lung adenocarcinoma (AC) demonstrates various histological subtypes within the tumour tissue. A panel established jointly by the IASLC, ATS and ERS classified invasive lung ACs based on the predominant histological subtype. We examined the distribution of tumours in lung AC patients according to histological subtype and analysed the effects of this classification on survival.

METHODS

The records of patients who had pulmonary resection for lung cancer between January 2000 and December 2009 were reviewed and 226 lung AC patients who fulfilled the inclusion criteria were identified. Histological subtypes of the ACs and their ratios in the tumour tissue were determined. Tumours were classified according to the predominant histological subtype and subsequently graded. The relationship between the predominant histological subtype, grade and survival were analysed.

RESULTS

Tumours were predominantly acinar in 99 cases (43.8%), solid in 89 (39.3%), lepidic in 20 (8.8%), and papillary in 11 (4.8%), whereas 7 tumours (3%) were variants of AC. Stage significantly affected survival (p = 0.001); however, the predominant histological subtype had no significant effect. The 5-year survival rate for patients with histologically grade II tumours was 48.6%, whereas that in patients with grade III tumours was 56%. (p = 0.69).

CONCLUSION

Invasive lung ACs may be defined by their predominant histological subtype. However, it is not yet possible to conclude that this classification is related to survival.

Does lung adenocarcinoma subtype predict patient survival?: A clinicopathologic study based on the new International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society international multidisciplinary lung adenocarcinoma classification

INTRODUCTION

Lung adenocarcinoma is a heterogeneous group of tumors with a highly variable prognosis, not well predicted by the current pathologic classification system. The 2004 World Health Organization classification results in virtually all tumors encountered in clinical practice being allocated to the adenocarcinoma of mixed subtype category. A new classification developed by an international multidisciplinary expert panel sponsored by the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society, is based on histomorphologic subtype and has recently been validated in a North American series of 514 stage I lung adenocarcinomas. We investigated the relationship between the new classification and patient survival in a series of Australian patients with stages I, II, and III lung adenocarcinoma.

METHODS

We identified 210 patients from a surgical database who underwent resection of lung adenocarcinoma from 1996 to 2009. Two pathologists, blinded to patient outcome, independently performed histopathologic subtyping according to the new classification. Kaplan-Meier curves were used to calculate 5-year survival for each separate histopathologic subtype/variant. Univariate and multivariate analyses were undertaken to control for validated prognostic factors.

RESULTS

We confirmed that the new subtypes of adenocarcinoma in situ, minimally invasive adenocarcinoma and lepidic-predominant adenocarcinoma had a 5-year survival approaching 100%, whereas micropapillary-predominant and solid with mucin-predominant adenocarcinomas were associated with particularly poor survival. Papillary-predominant and acinar-predominant adenocarcinomas had an intermediate prognosis. This effect persisted after controlling for stage.

CONCLUSIONS

Classification of lung adenocarcinoma according to the new International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification correlated with 5-year survival. These relationships persisted after controlling for known prognostic patient and tumor characteristics. The new classification has advantages not only for individual patient care but also for better selection and stratification for clinical trials and molecular studies.

A novel method for isolating individual cellular components from the adult human distal lung

A variety of lung diseases, such as pulmonary emphysema and idiopathic pulmonary fibrosis, develop in the lung alveoli. Multiple cell types are localized in the alveoli, including epithelial, mesenchymal, and endothelial cells. These resident cells participate in the pathogenesis of lung disease in various ways. To elaborate clearly on the mechanisms of these pathologic processes, cell type-specific analyses of lung disease are required. However, no method exists for individually isolating the different types of cells found in the alveoli. We report on the development of a FACS-based method for the direct isolation of individual cell types from the adult human distal lung. We obtained human lung tissue from lung resections, and prepared single-cell suspension. After depleting CD45-positive cells, a combination of antibodies against epithelial cell adhesion molecule (EpCAM), T1α, and vascular endothelial (VE)-cadherin as used to delineate alveolar cell types. Alveolar Type II cells were highly purified in the EpCAM(hi)/T1α(-) subset, whereas the EpCAM(+)/T1α(-/low) subset contained a mixed epithelial population consisting of alveolar Type I and bronchiolar epithelial cells. The EpCAM(-)/T1α(-) subset included both microvascular endothelial and mesenchymal cells, and these were separated by immunoreactivity to VE-cadherin. Lymphatic endothelial cells existed in the EpCAM(-)/T1α(hi) subset. Isolated cells were viable, and further cell culture studies could be performed. These results suggest that this novel method enables the isolation of different cellular components from normal and diseased lungs, and is capable of elucidating phenotypes specific to certain alveolar cell types indicative of lung disease.

Revolution in lung cancer: new challenges for the surgical pathologist

CONTEXT

Traditionally, lung cancer has been viewed as an aggressive, relentlessly progressive disease with few treatment options and poor survival. The traditional role of the pathologist has been primarily to differentiate small cell carcinoma from non-small cell carcinoma on biopsy and cytology specimens and to stage non-small cell carcinomas that underwent resection. In recent years, our concepts of lung cancer have undergone a revolution, including (1) the advent of successful, new, molecular-targeted therapies for lung cancer, many of which are associated with specific histologic cell types and subtypes; (2) new observations on the natural history of lung cancer derived from ongoing high-resolution computed tomography screening studies and recent histologic findings; and (3) proposals to revise the classification of lung cancers, particularly adenocarcinomas, in part because of the first 2 developments.

OBJECTIVE

To summarize the important, new developments in lung cancer, emphasizing the role of the surgical pathologist in personalized care for patients with lung cancer.

DATA SOURCES

Information about the new developments in lung cancer was obtained from the peer-review medical literature and the authors' experiences.

CONCLUSIONS

For decades, we have perceived lung cancer as a relentlessly aggressive and mostly incurable disease for which the surgical pathologist had a limited role. Today, surgical pathologists have an important and expanding role in the diagnosis and treatment of lung cancer, and it is essential to keep informed of new advances.

Bronchioloalveolar carcinoma and the significance of invasion: predicting biologic behavior

A resected adenocarcinoma illustrates challenges in diagnosing bronchioloalveolar carcinoma (BAC). Bronchioloalveolar carcinoma is defined by lack of invasion, something that may be difficult to assess in scars. Small (≤0.5 cm) invasive foci have little impact on the good prognosis associated with low-stage tumors. The term microinvasive adenocarcinoma or minimally invasive adenocarcinoma has been proposed for otherwise typical BACs and small invasive foci measuring 0.5 cm or less. Larger areas of invasion are associated with a more aggressive course and more reliably distinguish BAC from other variants of adenocarcinoma. Separating BAC from other forms of adenocarcinoma is important owing to differences in prognosis and emerging therapeutic strategies.

Genetic evolution of epidermal growth factor receptor in adenocarcinoma with a bronchioloalveolar carcinoma component

BACKGROUND

Epidermal growth factor receptor (EGFR) mutations may accumulate during the multistage progression of bronchioloalveolar carcinoma (BAC), leading to heterogeneity within the tumor. This study sought to determine whether metachronous adenocarcinomas with a BAC component emerging in the lung field arise from a single or multiple clones in the same individual.

MATERIALS AND METHODS

Samples of adenocarcinomas exhibiting various degrees of BAC were obtained by thoracotomy. Sequential specimens were obtained upon detection of metachronous lesions in the lung field. Genomic DNA was extracted from specimens, and the presence of activating mutations in EGFR was determined via direct sequencing. Our pathologic findings, sequential image information, and genetic data were compared to track evidence of cancer evolution.

RESULTS

Based on EGFR gene analyses of tumor specimens from 431 patients, 17 cases of sequential BAC-related adenocarcinomas, obtained by thoracotomy, were noteworthy. Upon alteration of the BAC/adenocarcinoma components, the EGFR tyrosine kinase inhibitor-untreated series, which had at least one episode of an EGFR-activating mutation, represented 3 potential hypotheses: no significant EGFR evolution for a single clone, genetic alterations from mutant to wild-type EGFR for multifocal lesions, or a switch from wild-type to mutant EGFR, leading to indeterminable cancer progression.

CONCLUSION

Genetic analysis, in conjunction with pathologic and radiologic diagnoses, can be used to explore the origin of multifocal BAC. The single-clone model indicates subsequent disease progression, whereas genetic alterations from mutations to wild-type EGFR are suggestive of second primary carcinoma. In cases when additional lesions emerge after the radical resection of BAC-related lung cancer, sequential tumor samples should be obtained for further evaluation.

Mixed Adenocarcinomas of the Lung: Place in New Proposals in Classification, Mandatory for Target Therapy

Context.—Lung cancer is one of the most frequent and lethal malignant neoplasms, but knowledge regarding the molecular basis of its pathogenesis is far from complete due to the striking diversity of different forms. The current lung cancer classification (World Health Organization 2004) can efficiently distinguish clinically relevant major subtypes (small cell and non–small cell carcinomas), but its results are partly inadequate when facing prognostic and therapeutic decisions for non–small cell carcinomas, especially for the group of tumors classified as adenocarcinoma. Lung adenocarcinoma comprises a heterogeneous group of tumors characterized by diverse morphologic features and molecular pathogenesis. The category of mixed adenocarcinomas includes most adenocarcinomas (approximately 80%) and, according to World Health Organization criteria, is defined by the occurrence of a mixed array of different patterns (acinar, papillary, bronchioloalveolar, solid with mucin). The histologic recognition of mixed adenocarcinoma is subjective and cannot consistently discriminate between responders and nonresponders to new targeted therapies (eg, tyrosine kinase inhibitors). Diagnostic problems are mainly related to the poor reproducibility of histologic criteria, especially when applied in small biopsies and cytology, and to the difficulty in assigning each form to a precisely defined entity, as needed by updated therapeutic approaches. In this evolving scenario, pathologists face new challenging diagnostic roles that include not only the precise morphologic definition of carcinoma subtypes but also their molecular characterization.

Objective.—To use a comprehensive critical analysis reconciling the overwhelming variety of biologic, morphologic, molecular, and clinical data to define new classification schemes for lung adenocarcinoma.

Data Sources.—Scientific literature and personal data were used.

Conclusions.—A new classification approach should redefine lung adenocarcinoma heterogeneity reconciling classic morphology, immunophenotypic and molecular features of neoplastic cells, and also relevant information provided by stem cell biology. This approach, which has been already successfully applied in World Health Organization classification of other tumors, could improve the recognition of new reproducible profiles for adenocarcinomas, more closely and reproducibly related to clinical features and response to specific therapies, limiting the use of “wastebasket” categories such as mixed adenocarcinoma.

Update in neoplastic lung diseases and mesothelioma

CONTEXT

Lung cancer is a common disease frequently seen by the surgical pathologist. Although secondary to improvements in screening and radiologic techniques and aggressive resection of small pulmonary nodules, the diagnosis of preneoplastic lesions is increasing in frequency and importance. Consequently, a greater understanding of their role in the development of lung carcinoma is needed for optimal patient care. Two lesions often encountered as small pulmonary nodules are bronchioloalveolar carcinoma and adenocarcinoma, which can be challenging to distinguish. Recently, updates to the TNM classification of non-small cell lung carcinoma have been reported that directly impact prognosis and treatment algorithms. Identification of new molecular targets in pleural mesothelioma and in preneoplastic lesions may lead to improved therapeutic strategies.

OBJECTIVE

To present recent advances in our understanding of neoplastic lung diseases and mesothelioma and to describe how these advances relate to the current practice of pulmonary pathology.

DATA SOURCES

Published literature from PubMed (National Library of Medicine) and primary material from the authors' institution.

CONCLUSIONS

It is important for the surgical pathologist to understand current diagnostic classifications of non-small cell lung cancer and to be aware of the range of preneoplastic lesions, as well as the features useful for distinguishing bronchioloalveolar carcinoma from adenocarcinoma in small pulmonary nodules. Although pleural mesothelioma has distinct features, it can also overlap histologically with adenocarcinoma, and immunohistochemistry can greatly aid in accurate diagnosis. New therapies targeting molecular markers in both non-small cell lung cancer and mesothelioma rely on accurate histopathologic diagnosis of these entities.

First-line treatment in advanced non-small-cell lung cancer: the emerging role of the histologic subtype

Lung cancer is the leading cause of cancer mortality worldwide. During the past quarter of a century, there have been definite steps forward in understanding the biology of this disease. However, progress in the treatment of advanced non-small-cell lung cancer (NSCLC) has been more elusive and has not been associated with a realistic probability of long-term survival. For this disease, platinum-based chemotherapy is currently the standard treatment. Numerous studies have compared various platinum doublets and have concluded that all such combinations are comparable in their clinical efficacy. Moreover, several trials evaluating different chemotherapy regimens in NSCLC have failed to document a difference based on histology. Recent evidence suggests that histology represents an important variable in the decision making. This review will discuss this new evidence in the first-line treatment of advanced NSCLC, focusing on different possible therapeutic approaches according to histologic subtype.

Minimally invasive adenocarcinomas of the lung

Current World Health Organization (WHO) classification of lung adenocarcinomas includes noninvasive bronchioloalveolar carcinoma (BAC) and several patterns of invasive adenocarcinoma. The most common is a mixed subtype of adenocarcinoma. This group is very heterogenous and includes a wide spectrum of tumors ranging from adenocarcinomas with a dominant BAC growth pattern (lepidic growth) to frankly invasive adenocarcinoma with no BAC component. There is a tendency among clinicians to regard tumor as BAC if any significant amount of lepidic growth pattern within the tumor is identified. The change in WHO definition of BAC and introduction of mixed subtype of adenocarcinoma resulted in disconnect between surgical pathologists and clinicians regarding the use of terminology and criteria for diagnosis of BAC and mixed subtype of adenocarcinoma. It is clear that pure BAC is an extremely rare tumor, whereas mixed subtypes of adenocarcinomas may have various clinical presentations and outcomes. The mounting evidence suggests that a subset of mixed subtype of adenocarcinomas with areas of BAC and focal invasion probably represent more indolent tumors. On the basis of the published data, there is a proposal to define a subcategory of "minimally invasive adenocarcinoma" of the lung. Many morphologic factors seem to play a role in predicting the behavior of these tumors. Depending on the results of ongoing clinical trials, surgical management of these tumors may change in a near future.

EGFR and K-ras mutations along the spectrum of pulmonary epithelial tumors of the lung and elaboration of a combined clinicopathologic and molecular scoring system to predict clinical responsiveness to EGFR inhibitors

We tested 418 neoplasms along the whole spectrum of primary lung tumor histotypes for epidermal growth factor receptor (EGFR) and K-ras mutations. Clinicopathologic data from 154 patients undergoing treatment with EGFR tyrosine kinase inhibitors (TKIs) were retrospectively studied. A scoring system assigning a score for each positive or negative characteristic (+1, female sex, nonsmoking status, adenocarcinoma histotype, Asian ethnicity, and EGFR mutation; -1, current smoker and K-ras mutation; and 0, male sex, ex-smoker, nonadenocarcinoma histotype, and no mutations) was elaborated and tested with EGFR-TKI response. Salivary gland-type, mucin-rich, and neuroendocrine tumors do not harbor EGFR mutations. A subset of nonmucinous adenocarcinomas, not necessarily of the bronchioloalveolar type, is related to EGFR mutations. Three probability groups significantly correlating with response to EGFR-TKIs were identified. Of note, the addition of molecular results did not significantly change the predictive value obtained by the combination of clinicopathologic characteristics alone in this scoring system. K-ras mutations, significantly associated with the mucin-secreting type of adenocarcinoma, consistently predict lack of response in white patients.

Pulmonary Preneoplasia

Context.—Improved screening techniques for lung cancer have resulted in detection of lesions that are considered to represent precursors of invasive lung carcinomas. These lesions may cause a diagnostic dilemma particularly on small biopsy or cytology specimens. Ancillary studies are usually not helpful, and diagnosis is based on morphology alone. Recognition of these lesions is very important to prevent potential diagnostic mistakes that may result in inadequate patient management. Future molecular studies may provide clinically useful diagnostic and prognostic gene markers.

Objective.—To review currently proposed morphologic criteria for precursor lesions of non–small cell lung carcinomas including squamous dysplasias, atypical adenomatous hyperplasia, and diffuse idiopathic neuroendocrine cell hyperplasia. Major molecular abnormalities are briefly discussed.

Data Sources.—Published literature and recent World Health Organization classification of lung tumors.

Conclusions.—Practicing surgical pathologists must be familiar with morphology of recognized pulmonary preneoplastic lesions that are more frequently detected radiographically and subjected to diagnostic procedures. Future understanding of underlying molecular abnormalities associated with progression of these lesions into invasive lung carcinoma may result in a development of molecular assays with potential diagnostic and prognostic importance.