Peripheral lung adenocarcinoma: correlation of thin-section CT findings with histologic prognostic factors and survival

Epidermal growth factor receptor mutations and anaplastic lymphoma kinase rearrangements in lung cancer with nodular ground-glass opacity

Background

Nodular ground-glass opacities (nGGO) are a specific type of lung adenocarcinoma. ALK rearrangements and driver mutations such as EGFR and K-ras are frequently found in all types of lung adenocarcinoma. EGFR mutations play a role in the early carcinogenesis of nGGOs, but the role of ALK rearrangement remains unknown.

Methods

We studied 217 nGGOs resected from 215 lung cancer patients. Pathology, tumor size, tumor disappearance rate, and the EGFR and ALK markers were analyzed.

Results

All but one of the resected nGGOs were adenocarcinomas. ALK rearrangements and EGFR mutations were found in 6 (2.8%) and 119 (54.8%) cases. The frequency of ALK rearrangement in nGGO was significantly lower than previously reported in adenocarcinoma. Advanced disease stage (p = 0.018) and larger tumor size (p = 0.037) were more frequent in the ALK rearrangement-positive group than in ALK rearrangement-negative patients. nGGOs with ALK rearrangements were associated with significantly higher pathologic stage and larger maximal and solid diameter in comparison to EGFR-mutated lesions.

Conclusion

ALK rearrangement is rare in lung cancer with nGGOs, but is associated with advanced stage and larger tumor size, suggesting its association with aggressive progression of lung adenocarcinoma. ALK rearrangement may not be important in early pathogenesis of nGGO.

[Management of subsolid pulmonary nodules]

The finding of subsolid pulmonary nodules poses a frequent problem in the daily routine of the radiologist. The biological behavior of such subsolid lesions differs significantly from solid nodules. The risk of malignancy is significantly higher in subsolid nodules as compared to solid or purely ground glass opacities or nodules. The recommendations regarding the diagnostic management of subsolid nodules have been adapted according to the tendency of growth and the risk of malignancy. A benign etiology is also seen quite often in subsolid lesions and in this case they will show a reduction of size or disappear completely by the follow-up examination. Therefore, in many cases a short-term follow-up examination is primarily recommended. As the findings will often show no changes for a long period of time, further annual follow-up examinations over a longer, not yet specified period of time are recommended. Subsolid lesions that grow in size and/or show an increase in density or develop a solid part within a ground glass lesion should remain as suspected malignancies until proven otherwise.

Prediction of pathologic prognostic factors in patients with lung adenocarcinomas: comparison of thin-section computed tomography and positron emission tomography/computed tomography

Background

The ratio of the maximum diameter of consolidation to the maximum tumor diameter (C/T ratio) on thin-section computed tomography (TSCT) and the maximum standardized uptake value (SUVmax) on ¹⁸ F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) are often used as preoperative independent variables to evaluate the invasiveness of lung adenocarcinoma. We investigated the associations between these independent variables and pathologic invasiveness in pulmonary adenocarcinomas.

Methods

We selected patients with peripheral lung adenocarcinomas, definitively diagnosed by surgical resection, with diameters of ≤ 30 mm over a 4-year period ending in December 2010. The association between 3 independent variables (tumor size, SUVmax, and C/T ratio) and pathologic prognostic factors was evaluated using logistic analysis.

Results

We evaluated a total of 163 primary lung adenocarcinomas in 148 patients (93 males and 55 females; age range: 34 to 84 years). Using multivariate logistic regression analysis, SUVmax and the C/T ratio were significantly associated with tumor invasiveness (odds ratio [OR] = 1.227; p = 0.025 and OR = 1.019; p = 0.008, respectively). Tumor size was not associated with invasiveness (OR = 1.003; p = 0.925). For solid type adenocarcinomas, only SUVmax was significantly associated with invasiveness (OR = 1.558; p = 0.003). For subsolid type adenocarcinomas, only the C/T ratio was significantly associated with invasiveness (OR = 1.030; p = 0.009).

Conclusions

Both the C/T ratio and the SUVmax are significantly correlated with pathologic invasiveness in patients with small lung adenocarcinomas, while there was a difference between the 2 evaluations. Solid type adenocarcinomas with SUVmax values of ≥ 4.4 and subsolid type adenocarcinomas with C/T ratio ≥ 53% were so highly invasive.

Pure ground-glass opacity neoplastic lung nodules: histopathology, imaging, and management

OBJECTIVE

The purpose of this article is to discuss histologic diagnosis of pure pulmonary ground-glass opacity nodules (GGNs), high-resolution CT (HRCT) findings and pathologic correlation, and management.

CONCLUSION

When pure GGNs are greater than 15 mm in diameter with nodularity or have high pixel attenuation (>-472 HU), the nodules are more likely to be invasive adenocarcinomas. Sublobar resection with a secured safety margin and without nodal dissection is performed for HRCT-suggested pure-GGN invasive adenocarcinomas and has a 100% 5-year survival rate.

Thin-section CT findings in peripheral lung cancer of 3 cm or smaller: are there any characteristic features for predicting tumor histology or do they depend only on tumor size?

BACKGROUND

Ground-glass opacity (GGO) is reported to be characteristic to lepidic growth of neoplasm in subsolid nodules. In solid nodules of lung cancer, however, there is no characteristic feature to be reported.

PURPOSE

To study if there are any thin-section CT findings characteristic to tumor histology or if they are only related to tumor size in solid nodules of the lung cancer.

MATERIAL AND METHODS

This study included 106 solid peripheral lung cancers of 3 cm or smaller (56 adenocarcinomas, 33 squamous cell carcinomas, and 17 small cell carcinomas) in which 16-slice CT with 1 mm collimation was performed before surgery. Six morphologic findings (presence or absence of lobulation, coarse spiculation, air bronchogram, cavity, pleural tag, and pleural-based lesion) and four measurements (ratio of the greatest transverse and vertical diameter to the shortest transverse diameter and density of lobulation and coarse spiculation) on thin-section CT images were evaluated. Density of lobulation (coarse spiculation) was defined as the ratio of lobulation (coarse spiculation) number to the greatest transverse diameter of a nodule.

RESULTS

Air bronchogram (P < 0.01) was the only significant factor for predicting lung adenocarcinoma. The prevalence of air bronchogram was significantly greater in adenocarcinoma than in squamous cell carcinoma (P < 0.01) or small cell carcinoma (P < 0.01). As the tumor size advanced, significantly positive linear trends were seen in the prevalence of lobulation (P < 0.01), coarse spiculation (P < 0.01), and pleural tag (P < 0.01), and the mean values of density of lobulation (P < 0.01) and coarse spiculation (P < 0.01), while the significant negative linear trend was seen in the ratio of vertical diameter to the shortest transverse (P = 0.02).

CONCLUSION

Air bronchogram on thin-section CT is characteristic feature of solid adenocarcinoma of the lung. However, other thin-section CT findings are irrelevant to tumor histology and related only to tumor size.

Reproducibility and Prognosis of Quantitative Features Extracted from CT Images

We study the reproducibility of quantitative imaging features that are used to describe tumor shape, size, and texture from computed tomography (CT) scans of non-small cell lung cancer (NSCLC). CT images are dependent on various scanning factors. We focus on characterizing image features that are reproducible in the presence of variations due to patient factors and segmentation methods. Thirty-two NSCLC nonenhanced lung CT scans were obtained from the Reference Image Database to Evaluate Response data set. The tumors were segmented using both manual (radiologist expert) and ensemble (software-automated) methods. A set of features (219 three-dimensional and 110 two-dimensional) was computed, and quantitative image features were statistically filtered to identify a subset of reproducible and nonredundant features. The variability in the repeated experiment was measured by the test-retest concordance correlation coefficient (CCCTreT). The natural range in the features, normalized to variance, was measured by the dynamic range (DR). In this study, there were 29 features across segmentation methods found with CCCTreT and DR ≥ 0.9 and R(2) Bet ≥ 0.95. These reproducible features were tested for predicting radiologist prognostic score; some texture features (run-length and Laws kernels) had an area under the curve of 0.9. The representative features were tested for their prognostic capabilities using an independent NSCLC data set (59 lung adenocarcinomas), where one of the texture features, run-length gray-level nonuniformity, was statistically significant in separating the samples into survival groups (P ≤ .046).

Primary intrathoracic malignant mesenchymal tumours: computed tomography features of a rare group of chest neoplasms

Objectives

To describe the computed tomography (CT) features in a case series of primary intrathoracic extracardiac malignant mesenchymal tumours (sarcomas).

Methods

A 5-year retrospective research was conducted, and 18 patients were selected. CT exams were reviewed by two chest radiologists, blinded to tumour pathological type, origin and grade. Lesions were described in relation to location, size, shape, margins, enhancement, presence of cavitation, calcifications, ground glass component, intratumoural enhanced vessels, pleural effusion, pleural tags, lymphangitis, chest wall/rib involvement and pathological lymph nodes.

Results

The readers described five pulmonary, six mediastinal and seven pleural/wall based lesions. Mean largest diameter was 103 mm. The most frequent shape was irregular (n = 12), most predominant margin was smooth (n = 12) and enhancement was mostly heterogeneous (n = 8). Intratumoural vessels and pleural effusion were seen in 11 patients. Pathological lymph nodes were present in four cases and calcifications in two cases.

Conclusions

Some frequent radiological features were described independently of tumour location and subtype. A sarcoma should be included as a major differential diagnosis when the radiologist faces an intrathoracic mass of large size (>70 mm) but with well defined smooth or lobulated margins, especially if presenting intratumoural vessels, associated pleural effusion but no significant lymphadenopathy.

Main messages

• Malignant mesenchymal tumours (sarcomas) are rare and can arise from any structure in the chest.

• Intrathoracic sarcomas show some frequent radiological features, independent of location and type.

• Some CT features may help the radiologist suspect for a sarcoma instead of other more common tumours.

Anaplastic lymphoma kinase gene rearrangements in patients with advanced-stage non-small-cell lung cancer: CT characteristics and response to chemotherapy

Few articles have been published on the imaging findings of anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer (NSCLC). To investigate the radiological findings of ALK-positive NSCLC in the advanced stage, CT scans were examined. In addition, the response to chemotherapy was evaluated. Of the 36 patients with ALK-rearranged NSCLC, a mass and a nodule were identified in 17 (47.2%) and 16 (44.4%), respectively, indicating that more than 40% had a small-sized tumor. Overall, 31 (86.1%) patients had lymphadenopathy, seven (19.4%) had extranodal lymph node invasion, and three (8.3%) had lymphangitis. A pleural effusion was seen in 15 patients (41.7%). All but one patient had no ground-glass opacity (GGO) lesions, indicating that most ALK-positive tumors showed a solid growth pattern without GGO on CT. Twenty were evaluable for response to chemotherapy; 10 (50.0%) had a partial response (PR), nine (45.0%) had stable disease (SD), and one (5.0%) had progressive disease (PD) with first-line chemotherapy. With second-line chemotherapy, five (26.3%) had PR, 11 (57.9%) had SD, and three (15.8%) had PD. The five patients with PR were all treated by using crizotinib. Time to progression was 8.2 months with first-line chemotherapy, and 6.0 months with second-line chemotherapy. Advanced-stage ALK-positive tumors have a relatively aggressive phenotype, which cannot be inferred from the size of the tumor alone. ALK-positive patients have a good response to first-line cytotoxic drugs and to crizotinib as second-line therapy, but a relatively poor response to cytotoxic drugs as second-line therapy.

The association between baseline clinical-radiological characteristics and growth of pulmonary nodules with ground-glass opacity

INTRODUCTION

Pulmonary nodules with ground-glass opacity (GGO) are frequently encountered; there is little consensus on appropriate monitoring of them. The purpose of this study was to clarify which baseline clinical and radiological characteristics were associated with growth of these nodules.

METHODS

We retrospectively studied patients with pulmonary nodules that met the following criteria: (1) lesion diameter of ≤3 cm, (2) GGO proportion of ≥50%, and (3) observation without treatment in the prior 6 months. Between 1999 and 2013, 120 pulmonary lesions in 67 patients fulfilled inclusion criteria. We evaluated changes in lesion size on serial computed tomography. Two endpoints, "time to 2-mm growth" and "incidence of 2-mm growth", were analyzed using Cox proportional hazards and logistic regression models, respectively.

RESULTS

At the median observation period of 4.2 years, 34 lesions exhibited growth by ≥2 mm, whereas 86 remained unchanged. Smoking history and initial lesion diameter were statistically significant variables in both time-to-event and regression analyses. Hazard ratio (HR) for smoking history was 3.67 (P<0.01). Compared with those ≤1 cm, HRs for 1.1-2 cm and 2.1-3 cm lesions were 2.23 (P=0.08) and 5.08 (P=0.04), respectively. Odds ratio (OR) for smoking history was 6.51 (P<0.01); OR for lesion diameter of 1.1-3 cm (versus ≤1 cm) was 4.06 (P=0.02).

CONCLUSION

Smoking history and initial lesion diameter are robustly associated with GGO growth. These results suggest that large GGOs, especially in smokers, warrant close follow-up to accurately monitor lesion growth.

Impact of the IASLC/ATS/ERS classification in pN0 pulmonary adenocarcinomas: a study with radiological-pathological comparisons and survival analyses

The aim of this study was: (1) to compare the new pathological findings as detected by the IASLC/ATS/ERS classification with the traditional radiological features in pulmonary pN0 adenocarcinomas, (2) to evaluate their prognostic significance on overall survival (OS). A total of 42 surgically resected pN0 pulmonary adenocarcinomas were analyzed. On CT scans, the following radiological data were recorded: sphericity, predominant margins, cavitation and bronchogram, attenuation and percentage of ground glass opacity (GGO). On pathological examination, tumors were categorized according to the IASLC/ATS/ERS classification; Sica score and grade, pathological stage, tumor major axis, pleural invasion, vascular and lymphatic invasion, peritumoral lymphoid infiltration, and cytological features were also determined. Clinical follow up was available in 37 cases (range 1-117 months). Radiologically, 31 solid and 11 semisolid tumors were found. Morphologically, 2 minimally invasive and 40 invasive adenocarcinomas were diagnosed. In radiological-pathological comparisons, (1) the acinar pattern was higher in tumors with solid attenuation and low GGO (p=0.018); (2) the lepidic pattern was more elevated in tumors with high GGO (p=0.012). In multivariate survival analyses with stage, predominant margins on CT scans (p=0.036) and Sica score (p=0.028) significantly affected OS. This study confirms the validity of the new classification of pulmonary adenocarcinomas in radiological-pathological comparisons and underlines the importance of both radiological and pathological findings in correctly identifying their prognostic features.

Nodule characterization: subsolid nodules

In this review, we focus on the radiologic, clinical, and pathologic aspects primarily of solitary subsolid pulmonary nodules. Particular emphasis will be placed on the pathologic classification and correlative computed tomography (CT) features of adenocarcinoma of the lung. The capabilities of fluorodeoxyglucose positron emission tomography-CT and histologic sampling techniques, including CT-guided biopsy, endoscopic-guided biopsy, and surgical resection, are discussed. Finally, recently proposed management guidelines by the Fleischner Society and the American College of Chest Physicians are reviewed.

Pathologic classification of adenocarcinoma of lung

Recently, the 1999/2004 World Health Organization (WHO) classification of adenocarcinoma became less useful from a clinical standpoint as most adenocarcinomas belonged to the mixed subtype and the term bronchioloalveolar carcinoma (BAC) gave rise to much confusion among clinicians. For these reasons a new adenocarcinoma classification was introduced in 2011 by a joint working group of the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS). This represents an international, multidisciplinary effort joining pathologists, molecular biologists, pulmonary physicians, thoracic oncologists, radiologists, and thoracic surgeons. Currently, a distinction is made between pre-invasive lesions, minimally invasive and invasive lesions. The confusing term BAC is not used anymore and new subcategories include adenocarcinoma in situ and minimally invasive adenocarcinoma. Several aspects of this classification are discussed with main emphasis on its correlation with imaging techniques and its impact on diagnosis, treatment and prognosis. On chest computed tomography (CT) a distinction is made between solid and subsolid nodules, the latter comprising ground glass opacities (GGO), and partly solid lesions. Several studies incorporating CT and positron emission tomographic (PET) data show a good imaging-pathologic correlation. With the implementation of screening programs early lung cancer has become a hotly debated topic and sublobar resection is currently reconsidered for early lesions without lymph node involvement. This new classification will also have an impact on the TNM classification. Thoracic surgeons will continue to play a major role in the application, evaluation and further refinement of this new adenocarcinoma classification.

How long should small lung lesions of ground-glass opacity be followed?

INTRODUCTION

Pulmonary ground-glass nodules are frequently encountered. The purpose of this study was to evaluate the natural history of them and to gain some insights on how to follow them up.

METHODS

We retrospectively studied patients with pulmonary nodules that met the following criteria: (1) tumor diameter of 3 cm or less, (2) ground-glass opacity proportion of 50% or more, and (3) observation without treatment for 6 months or more. Between 1999 and 2012, 108 pulmonary lesions in 61 patients fulfilled these criteria. We reevaluated their computed tomography images and analyzed changes in their size.

RESULTS

The tumors were 1 cm or lesser in size in 69 lesions, 1.1 cm to 2 cm in 34, and 2.1 cm to 3 cm in five. The proportion of solid lesions was 0% for 82 lesions, 1% to 25% for 19, and 26% to 50 % for seven. At the median observation period of 4.2 years, 29 lesions had become larger, whereas the remaining 79 had persisted without changing in size (±1 mm). The median size change in the nodules that grew was 7 mm (range, 2-32 mm). All 29 tumors began to grow within 3 years of their first observation: 1 year or lesser in 13 lesions, after 1.1 years to 2 years in 12, and after 2.1 years to 3 years in four.

CONCLUSIONS

Some small lung lesions exhibiting ground-glass opacity persisted without changes in size, whereas others grew gradually. The tendency to grow was clear within the first 3 years in all cases. Therefore, we conclude that these lesions should be followed for at least 3 years.

IASLC/ATS/ERS International Multidisciplinary Classification of Lung Adenocarcinoma: novel concepts and radiologic implications

In 2011, the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society proposed a new classification for lung adenocarcinoma that included a number of changes to previous classifications. This classification now considers resection specimens, small biopsies, and cytology specimens. Two former histopathologic terms, bronchioloalveolar carcinoma and mixed subtype adenocarcinoma, are no longer to be used. For resection specimens, the new terms of adenocarcinoma in situ and minimally invasive adenocarcinoma are introduced for small adenocarcinomas showing pure lepidic growth and predominantly lepidic growth, with invasion ≤5 mm, respectively. Invasive adenocarcinomas are now classified by their predominant pattern as lepidic, acinar, papillary, and solid; a micropapillary pattern is newly added. This classification also provides guidance for small biopsies and cytology specimens. For adenocarcinomas that include both an invasive and a lepidic component, it is suggested that for T staging the size of the T-factor may be best measured on the basis of the size of the invasive component rather than on the total size of tumors including lepidic components, both on pathologic and computed tomography assessment. This suggestion awaits confirmation in clinical-radiologic trials. An implication for M staging is that comprehensive histologic subtyping along with other histologic and molecular features can be very helpful in determining whether multiple pulmonary nodules are separate primaries or intrapulmonary metastases. In this review article, we provide an illustrated overview of the proposed new classification for lung adenocarcinoma with an emphasis upon what the radiologist needs to know in order to successfully contribute to the multidisciplinary strategic management of patients with this common histologic subtype of lung cancer.

Diagnosis of lung adenocarcinoma in resected specimens: implications of the 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification

A new lung adenocarcinoma classification has been published by the International Association for the Study of Lung Cancer, the American Thoracic Society, and the European Respiratory Society. This new classification is needed to provide uniform terminology and diagnostic criteria, most especially for bronchioloalveolar carcinoma. It was developed by an international core panel of experts representing all 3 societies with oncologists/pulmonologists, pathologists, radiologists, molecular biologists, and thoracic surgeons.This summary focuses on the aspects of this classification that address resection specimens. The terms bronchioloalveolar carcinoma and mixed subtype adenocarcinoma are no longer used. For resection specimens, new concepts are introduced, such as adenocarcinoma in situ and minimally invasive adenocarcinoma for small solitary adenocarcinomas with either pure lepidic growth (adenocarcinoma in situ) and predominant lepidic growth with invasion of 5 mm or less (minimally invasive adenocarcinoma), to define the condition of patients who will have 100% or near 100% disease-specific survival, respectively, if they undergo complete lesion resection. Adenocarcinoma in situ and minimally invasive adenocarcinoma are usually nonmucinous, but rarely may be mucinous. Invasive adenocarcinomas are now classified by predominant pattern after using comprehensive histologic subtyping with lepidic (formerly most mixed subtype tumors with nonmucinous bronchioloalveolar carcinoma), acinar, papillary, and solid patterns; micropapillary is added as a new histologic subtype. Variants include invasive mucinous adenocarcinoma (formerly mucinous bronchioloalveolar carcinoma), colloid, fetal, and enteric adenocarcinoma.It is possible that this classification may impact the next revision of the TNM staging classification, with adjustment of the size T factor according to only the invasive component pathologically in adenocarcinomas with lepidic areas.

The long-term course of ground-glass opacities detected on thin-section computed tomography

BACKGROUND

Focal ground-glass opacity (GGO) is becoming a major concern because of its possible association with lung cancer. In this study, we analyzed the long-term progression of GGOs that persisted for more than 2 years.

METHODS

We reviewed focal GGOs identified by thin-section computed tomography that persisted for more than 2 years.

RESULTS

We enrolled a total of 114 patients with 175 GGO lesions. The median patient age was 61 years (range, 37-92 years) and 42 (36.8%) patients were male. Mean initial GGO size was 7.8 ± 4.4 mm. Median follow-up duration was 45 months. Forty-six (26.3%) GGOs had significant size increases (≥2 mm in the longest diameter) with a mean volume doubling time of 1041 days. In a multivariate analysis, large size (≥10 mm), the presence of a solid portion (mixed GGO) and old age (≥65 years) were risk factors for significant size increase, with odds ratios (95% CI) of 6.46 (2.69-15.6), 2.69 (1.11-6.95) and 2.55 (1.13-5.77), respectively. GGOs with character changes from pure to mixed or mixed to solid showed more rapid volume expansion.

CONCLUSIONS

GGOs which persisted for several years showed an indolent course. Large lesions with a solid portion and GGOs in male or elderly individuals may be cause for more concern, as these factors were associated with size increase. Resection should be considered if GGOs show character changes, as these may be associated with rapid size progression.

Invasive pulmonary adenocarcinomas versus preinvasive lesions appearing as ground-glass nodules: differentiation by using CT features

PURPOSE

To retrospectively investigate the differentiating computed tomographic (CT) features between invasive pulmonary adenocarcinoma (IPA) and preinvasive lesions appearing as ground-glass nodules (GGNs) in 253 patients.

MATERIALS AND METHODS

This study was approved by the institutional review board. From January 2005 to October 2011, 272 GGNs were pathologically confirmed (179 IPAs and 93 preinvasive lesions) in 253 patients and were included in this study. There were 64 pure GGNs and 208 part-solid GGNs. Preinvasive lesions consisted of 21 atypical adenomatous hyperplasias and 72 adenocarcinomas in situ. To identify the differentiating CT features between IPAs and preinvasive lesions and to evaluate their differentiating accuracy, logistic regression analysis and receiver operating characteristic (ROC) curve analysis were performed, respectively.

RESULTS

In pure GGNs, preinvasive lesions were significantly smaller and more frequently nonlobulated than IPAs (P < .05). Multivariate analysis revealed that lesion size was the single significant differentiator of preinvasive lesions from IPAs (P = .029). The optimal cut-off size for preinvasive lesions was less than 10 mm (sensitivity, 53.33%; specificity, 100%). In part-solid GGNs, there were significant differences in lesion size, solid portion size, solid proportion, margin, border, and pleural retraction between IPAs and preinvasive lesions (P < .05). Multivariate analysis revealed that smaller lesion size, smaller solid proportion, nonlobulated border, and nonspiculated margin were significant differentiators of preinvasive lesions (P < .05), with excellent differentiating accuracy (area under ROC curve, 0.905).

CONCLUSION

In pure GGNs, a lesion size of less than 10 mm can be a very specific discriminator of preinvasive lesions from IPAs. In part-solid GGNs, preinvasive lesions can be accurately distinguished from IPAs by the smaller lesion size, smaller solid proportion, nonlobulated border, and nonspiculated margin.

Epidermal growth factor receptor mutation in lung adenocarcinomas: relationship with CT characteristics and histologic subtypes

PURPOSE

To retrospectively identify quantitative computed tomographic (CT) features that correlate with epidermal growth factor receptor (EGFR) mutation in surgically resected lung adenocarcinomas stratified by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS) classification in an East Asian cohort of patients known to have a high prevalence of EGFR mutations.

MATERIALS AND METHODS

An institutional review board approved this study and waived informed consent. In 153 surgically resected lung adenocarcinomas, EGFR mutation was determined by direct DNA sequencing. Histologic subtype was classified according to IASLC/ATS/ERS classification of lung adenocarcinoma. At preoperative chest CT, the percentage of ground-glass opacity (GGO) volume and total tumor volume of each tumor were measured by using a semiautomated algorithm. Distribution of EGFR mutation according to histologic subtype, percentage of GGO volume, and total tumor volume was evaluated by using the Fisher exact test, the Student t test, trend analysis, and multiple logistic regression analysis.

RESULTS

Exon 21 missense mutation was more frequent in lepidic predominant adenocarcinomas than in other histologic subtypes (odds ratio, 3.44; 95% confidence interval: 1.53, 7.74; P = .003). GGO volume percentage in tumors with exon 21 missense mutation (61.7% ± 31.9 [standard deviation]) was significantly higher than that in EGFR wild-type tumors (30.0% ± 38.5) (P = .0001) and exon 19-mutated tumors (28.9% ± 37.7) (P = .0006). A significant trend of prevalence of exon 21 missense mutation increasing along with increasing GGO volume (P = .0008) was found.

CONCLUSION

GGO volume percentage in tumors with exon 21 missense mutation was significantly higher than that in tumors with other EGFR mutation status. This can be related to the fact that exon 21 missense mutation was significantly more frequent in lepidic predominant adenocarcinomas, including adenocarcinoma in situ, minimally invasive adenocarcinoma, and lepidic predominant invasive adenocarcinoma, according to IASLE/ATS/ERS classification.

[Correlation between regional node metastasis and imageological characteristics in non-small cell lung cancer]

非小细胞肺癌（non-small cell lung cancer, NSCLC）局部淋巴结（N）分期是影响患者治疗方案选择的关键因素之一。目前临床所使用的无创和有创性N分期方法均有其局限性。研究发现NSCLC的某些影像学特点可预测淋巴结转移的危险性，包括大小、CT密度和氟代脱氧葡萄糖（fluorodeoxyglucose, FDG）标准化摄取值（standardized uptake value, SUV）等。期待系统性多因素分析，以发现影响肺癌淋巴结转移的关键因素。

Lung cancer with scattered consolidation: detection of new independent radiological category of peripheral lung cancer on thin-section computed tomography

OBJECTIVES

Ground glass opacity (GGO) on thin-section computed tomography (CT) has been reported to be a favourable prognostic marker in lung cancer, and the size or area of GGO is commonly used for preoperative evaluation. However, it can sometimes be difficult to evaluate the status of GGO.

METHODS

A retrospective study was conducted on 572 consecutive patients with resected lung cancer of clinical stage IA between 2004 and 2011. All patients underwent preoperative CT and their radiological findings were reviewed. The areas of consolidation and GGO were evaluated for all lung cancers. Lung cancers were divided into three categories on the basis of the status of GGO: GGO, part solid and pure solid. Lung cancers in which it was difficult to measure GGO were selected and their clinicopathological features were investigated.

RESULTS

Seventy-one (12.4%) patients had lung cancer in whom it was difficult to measure GGO. In all these cases, consolidation and GGO were not easily measured because of their scattered distribution. In this cohort, nodal metastases were not observed at all. The frequency of other pathological factors, such as lymphatic and/or vascular invasion, was significantly lower (P < 0.0001).

CONCLUSIONS

This new category of lung cancer with scattered consolidation on thin-section CT scan tended to be pathologically less invasive. When lung cancer has GGO and is difficult to measure because of a scattered distribution, its prognosis could be favourable regardless of the area of GGO. This new category could be useful for the preoperative evaluation of lung cancer.

Radiographic and pathological analysis of small lung adenocarcinoma using the new IASLC classification

AIM

To analyse the correlation between computed tomography (CT) findings of small lung adenocarcinomas and the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society Classification of Lung Adenocarcinoma.

MATERIALS AND METHODS

A retrospective review of 300 lung adenocarcinoma lesions (size ≤20 mm) after surgical resection in 295 consecutive patients was performed. Tumours were defined as air-containing type if the ratio of the maximum dimension of the tumour on mediastinal windows to the maximum dimension of the tumour on lung windows was ≤50%, and as solid-density type if the ratio was >50%. The incidence between CT findings (air bronchogram, vascular involvement, pleural tags, notches, and spiculation) and pathological findings were investigated.

RESULTS

Of the 142 air-containing lesions, 114 were adenocarcinoma in situ (AIS), 28 were minimally invasive adenocarcinoma (MIA), and none of the lesions were invasive adenocarcinoma. Of the 158 solid-density lesions, 30 were AIS, 24 were MIA, and 104 were invasive adenocarcinoma. Notches and pleural tags were commonly observed in cases of invasive adenocarcinoma (p < 0.05).

CONCLUSIONS

In the air-containing type of small lung adenocarcinomas, AIS and MIA were observed but no cases of invasive adenocarcinoma were found. The presence of notches and pleural tags were a significant factor in invasive adenocarcinoma.

Recommendations for the management of subsolid pulmonary nodules detected at CT: a statement from the Fleischner Society

This report is to complement the original Fleischner Society recommendations for incidentally detected solid nodules by proposing a set of recommendations specifically aimed at subsolid nodules. The development of a standardized approach to the interpretation and management of subsolid nodules remains critically important given that peripheral adenocarcinomas represent the most common type of lung cancer, with evidence of increasing frequency. Following an initial consideration of appropriate terminology to describe subsolid nodules and a brief review of the new classification system for peripheral lung adenocarcinomas sponsored by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS), six specific recommendations were made, three with regard to solitary subsolid nodules and three with regard to multiple subsolid nodules. Each recommendation is followed first by the rationales underlying the recommendation and then by specific pertinent remarks. Finally, issues for which future research is needed are discussed. The recommendations are the result of careful review of the literature now available regarding subsolid nodules. Given the complexity of these lesions, the current recommendations are more varied than the original Fleischner Society guidelines for solid nodules. It cannot be overemphasized that these guidelines must be interpreted in light of an individual's clinical history. Given the frequency with which subsolid nodules are encountered in daily clinical practice, and notwithstanding continuing controversy on many of these issues, it is anticipated that further refinements and modifications to these recommendations will be forthcoming as information continues to emerge from ongoing research.

Subsolid pulmonary nodules: imaging evaluation and strategic management

PURPOSE OF REVIEW

Given the higher rate of malignancy of subsolid pulmonary nodules and the considerably lower growth rate of ground-glass nodules (GGNs), dedicated standardized guidelines for management of these nodules have been proposed, including long-term low-dose computed tomography (CT) follow-up (≥3 years). Physicians must be familiar with the strategic management of subsolid pulmonary nodules, and should be able to identify imaging features that suggest invasive adenocarcinoma requiring a more aggressive management.

RECENT FINDINGS

Low-dose CT screening studies for early detection of lung cancer have increased our knowledge of pulmonary nodules, and in particular our understanding of the strong although imperfect correlation of the subsolid pulmonary nodules, including pure GGNs and part-solid nodules, with the spectrum of preinvasive to invasive lung adenocarcinoma. Serial CT imaging has shown stepwise progression in a subset of these nodules, characterized by increase in size and density of pure GGNs and development of a solid component, the latter usually indicating invasive adenocarcinoma.

SUMMARY

There is close correlation between the CT features of subsolid nodules (SSNs) and the spectrum of lung adenocarcinoma. Standardized guidelines are suggested for management of SSNs.

Primary adenocarcinoma of lung: a pictorial review of recent updates

Primary adenocarcinoma of lung has replaced squamous cell carcinoma as the commonest histological subtype of lung cancer and the incidence of primary lung adenocarcinoma appears to be rising. Although the main factors behind this 'epidemic-like' situation are largely undiscovered, filter cigarettes appear to significantly contribute to this shift in the histopathological spectrum. The new multidisciplinary classification of adenocarcinoma of lung was introduced to address advances in clinical, pathological, radiological and molecular sciences. The purpose of this essay is to discuss various classes of lung adenocarcinoma in the new classification with their classical imaging features on computed tomography and summarise the recent advances in the field of radiology and review radiology recommendations.

Prognostic value of the ratio of ground glass opacity on computed tomography in small lung adenocarcinoma: A meta-analysis

INTRODUCTION

Lung cancer is the leading cause of cancer-associated death. In many countries, adenocarcinoma is the most common histologic type in lung cancer. Previously, few factors are identified to be prognostic indicators for the patients with small lung adenocarcinoma. Recently, the ground glass opacity (GGO) area found on high-resolution computed tomography (HRCT) scanning was identified as a prognostic indicator in some studies. But no clear consensus has been defined.

METHODS

The PubMed/MEDLINE, EMBASE, Cochrane library and SpringerLink electronic databases were searched for articles related to ground glass opacity on computed tomography in patients with small lung adenocarcinoma. Data was extracted and analyzed independently by two investigators. An estimate of the hazard ratio (HR) for comparing high GGO ratio with low GGO ratio was extracted. The respective HRs was combined into a pooled HR, and 95% confidence interval (CI) was calculated for each study. The publication heterogeneity was assessed graphically using performing Beggs' funnel plot. All the statistical tests used in our meta-analysis were performed with STATA version 11.

RESULTS

Thirteen studies, encompassing 2,027 patients, were included in our meta-analysis. Ten of these studies revealed that the GGO ratio in small lung adenocarcinoma is a good prognostic indicator. Seven studies were combined in a meta-analysis using overall survival (OS) as the end point of interest. The weighted HR of 7 studies was 0.85, with relative 95% CI ranging from 0.78 to 0.93 (P=0.009). For the surgical patient population, the primary endpoint of relapse-free survival (RFS) was superior with high GGO area on computed tomography (The combined HR 0.82, 95% CI 0.74-0.90; P=0.007).

CONCLUSIONS

The result of our meta-analysis suggested that the GGO area measured on HRCT had a prognostic value of overall survival and relapse-free survival in small lung adenocarcinoma. The GGO ratio may be an independent prognostic factor for small lung adenocarcinoma.

Simple preoperative computed tomography image analysis shows good predictive performance for pathological vessel invasion in clinical stage IA non-small cell lung cancer

OBJECTIVES

Pathological vessel invasion is a well-known prognostic factor in early-stage, non-small cell lung cancer and preoperative predicting vessel invasion may enable us to improve prognosis by additional interventions. We evaluated the importance of vessel invasion as a prognostic factor in clinical stage IA non-small cell lung cancer and predictive performance of simple diameter-based computed tomography image analysis for vessel invasion.

METHODS

The study design was retrospective, and we reviewed 398 patients who underwent surgical resection of clinical stage IA non-small cell lung cancer from 1999 to 2009. The prognostic factors for recurrence-free survival were examined by univariate and multivariate analyses. Additionally, we analyzed preoperative high-resolution computed tomography images of patients with adenocarcinoma. The greatest diameter of the tumor in the lung window and the length of the consolidation part of L in the mediastinal window were measured. Then the ratio (mediastinal window/lung window) was calculated, and the correlation between the ratio (mediastinal window/lung window) and vessel invasion was analyzed by receiver operating characteristic analysis.

RESULTS

Sixty-eight recurrences occurred. Multivariate analysis revealed that vessel invasion, high preoperative serum carcinoembryonic antigen, and history of other malignancy were independent prognostic factors; their hazard ratios were 2.98, 2.45, and 1.98, respectively. The receiver operating characteristic analysis showed that the area under the curve was 0.75. When we set the cut-off value of the ratio (mediastinal window/lung window) at 0.67, the sensitivity and specificity were 75% and 72%, respectively.

CONCLUSIONS

Vessel invasion had the greatest impact on recurrence in clinical stage IA non-small cell lung cancer. Our simple computed tomography image analysis showed good predictive performance for vessel invasion.

Percutaneous computed tomography-guided coaxial core biopsy for small pulmonary lesions with ground-glass attenuation

INTRODUCTION

The aim of this study was to investigate the diagnostic value of percutaneous computed tomography (CT)-guided coaxial transthoracic needle biopsy (TNB) for small pulmonary lesions (≤ 3 cm) with persistent ground-glass opacity (GGO).

METHODS

From January 2004 to February 2010, consecutive patients with persistent small GGO lesions (≤ 3 cm) who underwent CT-guided TNB were analyzed. The pathologic results of CT-guided TNB were compared with final diagnoses, and the GGO percentage on CT was correlated with the stromal invasion in surgical pathology.

RESULTS

We performed CT-guided TNB on 1612 patients during the study period. Among them, 55 patients had persistent small GGO lesions (size range 0.5-3.0 cm; 1.72 ± 0.73 cm), 47 were diagnosed with lung adenocarcinomas, and 8 with benign nonspecific lesions. Minor procedure-related complications occurred in 26 patients (47.3%) with small pneumothorax and 11 patients (20.0%) with self-limited mild hemoptysis. The final diagnoses of the 43 patients receiving lobectomy were invasive adenocarcinoma (n = 23), pure bronchioloalveolar carcinoma (n = 19), and mucosa-associated lymphoid tissue lymphoma (n = 1). The diagnostic accuracy was 93.0% (40/43) using CT-guided TNB. Pure GGO lesions had a higher incidence of pure bronchioloalveolar carcinoma than GGO-dominant lesions (70.0% versus 21.7%; p = 0.004). Compared with surgical pathology, stromal invasion was underestimated in 43.5% (10/23) of the TNB specimens, especially in pure GGO lesions (83%, 5/6). In logistic regression analysis, the GGO percentage correlated inversely with stromal tumor invasion (p = 0.0028).

CONCLUSIONS

CT-guided coaxial TNB is a safe and useful method for diagnosing small (≤ 3 cm) persistent GGO lesions. Stromal invasion may be underestimated by TNB in GGO lesions.

Quantitative classification based on CT histogram analysis of non-small cell lung cancer: correlation with histopathological characteristics and recurrence-free survival

PURPOSE

Quantification of the CT appearance of non-small cell lung cancer (NSCLC) is of interest in a number of clinical and investigational applications. The purpose of this work is to present a quantitative five-category (α, β, γ, δ, and ɛ) classification method based on CT histogram analysis of NSCLC and to determine the prognostic value of this quantitative classification.

METHODS

Institutional review board approval and informed consent were obtained at the National Cancer Center Hospital. A total of 454 patients with NSCLC (maximum lesion size of 3 cm) were enrolled. Each lesion was measured using multidetector CT at the same tube voltage, reconstruction interval, beam collimation, and reconstructed slice thickness. Two observers segmented NSCLC nodules from the CT images by using a semi-automated three-dimensional technique. The two observers classified NSCLCs into one of five categories from the visual assessment of CT histograms obtained from each nodule segmentation result. Interobserver variability in the classification was computed with Cohen's κ statistic. Any disagreements were resolved by consensus between the two observers to define the gold standard of the classification. Using a classification and regression tree (CART), the authors obtained a decision tree for a quantitative five-category classification. To assess the impact of the nodule segmentation on the classification, the variability in classifications obtained by two decision trees for the nodule segmentation results was also calculated with the Cohen's κ statistic. The authors calculated the association of recurrence with prognostic factors including classification, sex, age, tumor diameter, smoking status, disease stage, histological type, lymphatic permeation, and vascular invasion using both univariate and multivariate Cox regression analyses.

RESULTS

The κ values for interobserver agreement of the classification using two nodule segmentation results were 0.921 (P < 0.001) and 0.903 (P < 0.001), respectively. The κ values for the variability in the classification task using two decision trees were 0.981 (P < 0.001) and 0.981 (P < 0.001), respectively. All the NSCLCs were classified into one of five categories (type α, n = 8; type β, n = 38; type γ, n = 103; type δ, n = 112; type ɛ, n = 193) by using a decision tree. Using a multivariate Cox regression analysis, the classification (hazard ratio 5.64; P = 0.008) and disease stage (hazard ratio 8.33; P < 0.001) were identified as being associated with an increased recurrence risk.

CONCLUSIONS

The quantitative five-category classifier presented here has the potential to provide an objective classification of NSCLC nodules that is strongly correlated with prognostic factors.

The tumour shape of lung adenocarcinoma is related to the postoperative prognosis

We evaluated the tumour shape as a potential prognostic indicator in lung adenocarcinoma patients. Among 994 patients who underwent curative surgery, 78 cases of adenocarcinoma (N0M0) with tumours ≥ 31 mm in diameter were reviewed. The patients were divided into two groups based on the ratio between the longest and the smallest axis length. The patients who had tumours whose ratios were > 0.5 were defined as the globular shape group (GL) and the others, whose ratio was 0.5 or less, were defined as the ellipse shape group (EL). The 78 patients were divided into two subgroups (57 in the GL and 21 in the EL). The tumour shape was related to the prognosis, and the 5-year overall survival (OS) rate in the GL was 51.5%, and that in the EL was 85.5% (P = 0.018). The 5-year disease-free survival rate of the GL was 46.6% and that of the EL patients was 85.0% (P = 0.04). The multivariate analysis showed that the shape of the tumour and the presence of pleural invasion were the independent and significant factors predicting the OS (P = 0.04 and P < 0.01, respectively). In adenocarcinoma patients, the shape of the tumour is related to the postoperative survival.

Clinicoradiologic characteristics of patients with lung adenocarcinoma harboring EML4-ALK fusion oncogene

INTRODUCTION

The fusion oncogene of echinoderm microtubule-associated protein like 4 (EML4) and anaplastic lymphoma kinase (ALK) defines a new molecular subset of non-small-cell lung cancer. We explored the EML4-ALK gene in a relatively large cohort and reviewed the clinicoradiologic background of the patients.

METHODS

We studied 720 patients with lung adenocarcinoma. The clinicopathological characteristics of each patient were compared among the subgroups stratified by the EML4-ALK gene status. For radiographic evaluation, we scored the proportion of the ground-glass opacity (GGO) component and calculated the tumor disappearance rate (TDR) in each tumor in the cohort of 168 patients that were extracted by using a case-matching procedure.

RESULTS

Twenty-eight (3.9%) patients harbored the EML4-ALK gene. Younger age (p=0.001), no or light history of smoking (p=0.05) and normal serum carcinoembryonic antigen (CEA) level (p=0.04) were characteristics of the patients with EML4-ALK. No significant difference was observed for overall and disease free survival between the two groups. All but one tumor in the EML4-ALK-positive group exhibited no GGO, whereas half of the tumors (69/140 patients) in the EML4-ALK-negative group exhibited some GGO (p=0.0004). The mean TDRs were 0.33 and 0.54, respectively, which was significantly lower in the positive group (p=0.0006).

CONCLUSIONS

We identified younger age, no or light history of smoking, and normal serum CEA as clinical features of patients with EML4-ALK-positive lung adenocarcinoma. In addition, EML4-ALK-positive tumors exhibited a solid pattern on CT. These features may be of value in predicting for patient selection for ALK inhibition therapy in the absence of genetic screening.

Accuracy and predictive features of FDG-PET/CT and CT for diagnosis of lymph node metastasis of T1 non-small-cell lung cancer manifesting as a subsolid nodule

OBJECTIVES

To retrospectively evaluate the diagnostic accuracy and predictive features of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG-PET/CT) and CT in lymph node (LN) staging of T1 non-small-cell lung cancers (NSCLCs) manifesting as subsolid nodules.

METHODS

From January 2005 to May 2011, 160 patients with pathologically proven T1 subsolid NSCLCs with LN staging were included in this study. Diagnostic accuracies of FDG-PET/CT and CT for LN staging were evaluated. Maximum standardised uptake value (SUVmax) and CT features of primary tumours were evaluated to investigate predictive factors for LN metastasis.

RESULTS

LN metastases were found in nine of the 160 patients (5.6%). No LN metastasis was present in patients with a solid proportion ≤50%. Sensitivity, specificity and accuracy of FDG-PET/CT for LN staging on a per-patient basis were 11.1%, 86.1% and 81.9%; those of CT were 11.1%, 96.7% and 91.9%. Among patients with a solid proportion >50%, there were significant differences in SUVmax, solid portion size, solid proportion and lesion location between patients with and without LN metastasis. Multivariate analysis revealed that higher SUVmax, a larger solid proportion and central location were independent predictors of LN metastasis.

CONCLUSIONS

FDG-PET/CT adds little value to CT in the lymph node staging of T1 subsolid NSCLCs.

KEY POINTS

Lymph node (LN) metastases are important in non-small-cell lung cancer (NSCLC). • Positron emission tomography (PET) helps to stage solid NSCLCs. • FDG-PET/CT adds little to the LN staging of T1 subsolid NSCLCs. • No LN metastasis in patients with a solid proportion ≤50%. • LN metastasis is more common in solid and/or centrally sited tumours.

Small peripheral lung adenocarcinoma: CT and histopathologic characteristics and prognostic implications

Since the introduction of computed tomography (CT), detection of small lung cancer, especially small peripheral adenocarcinoma, is common. Recently, the morphological characteristics, including thin-section CT and pathologic findings, and prognosis of small peripheral lung adenocarcinomas have been studied extensively. The radiologic and microscopic findings correlate well with each other and are closely associated with tumour prognosis. Most importantly, some subtypes of small lung adenocarcinomas with specific CT or pathologic features are curable. Therefore, all defining characteristics (CT, pathologic and prognostic) of this kind of tumour should be integrated to improve our understanding, provide guidelines for management and accurately assess its prognosis.

A Study of Surgically Resected Peripheral Non-Small Cell Lung Cancer with a Tumor Diameter of 1.0 CM or Less

Background and Aims:

The widespread use of high resolution computed tomography has increased the number of small peripheral lung cancers. This study reviewed the clinicopathological features of the patients with non-small cell lung cancer (NSCLC) with a tumor diameter of 1 cm or less, in order to explore the adequate management of such small sized lung cancers.

Material and Methods:

This study was a retrospective analysis of consecutive 58 patients (5.3% out of 1095 patients) who underwent a complete resection for a peripheral NSCLC with a diameter of 1.0 cm or less. The clinical features and outcomes were compared with 203 patients with NSCLC with a diameter between 1.1 and 2.0 cm.

Results:

The mean age was 64.5 years and there were 26 males and 32 females. Clinical stage was IA in 57 (98%) and IIIA in 1. Lobectomy was performed in 39 patients, segmentectomy in nine, and nonanatomic wedge resection in ten. Two patients, who underwent systemic lymph node dissection, had mediastinal lymph node metastasis and were diagnosed as pathological stage IIIA; however they did not relapse after surgery. One patient with pathological stage IA papillary adenocarcinoma died due to brain metastases. The five-year overall survival rate and disease free survival rate was 95.0% and 95.3%, respectively. Patients with NSCLC of 1.0 cm or less showed significantly better survival than those with tumors measuring 1.1–2.0 cm in size (p = 0.048).

Discussion:

The indications for avoiding systemic lymph node dissection for operable NSCLC should not be based on the size of the tumor. A small-sized lung cancer might be surgically treated before the tumor enlarges to more than 1.0 cm in size.

3D automatic exposure control for 64-detector row CT: radiation dose reduction in chest phantom study

PURPOSE

The purpose of this study was to determine the utility of three-dimensional (3D) automatic exposure control (AEC) for low-dose CT examination in a chest phantom study.

MATERIALS AND METHODS

A chest CT phantom including simulated focal ground-glass opacities (GGOs) and nodules was scanned with a 64-detector row CT with and without AEC. Performance of 3D AEC included changing targeted standard deviations (SDs) of image noise from scout view. To determine the appropriate targeted SD number for identification, the capability of overall identification with the CT protocol adapted to each of the targeted SDs was compared with that obtained with CT without AEC by means of receiver operating characteristic analysis.

RESULTS

When targeted SD values equal to or higher than 250 were used, areas under the curve (Azs) of nodule identification with CT protocol using AEC were significantly smaller than that for CT protocol without AEC (p < 0.05). When targeted SD numbers at equal to or more than 180 were adapted, Azs of CT protocol with AEC had significantly smaller than that without AEC (p < 0.05).

CONCLUSION

This phantom study shows 3D AEC is useful for low-dose lung CT examination, and can reduce the radiation dose while maintaining good identification capability and good image quality.