Progression of focal pure ground-glass opacity detected by low-dose helical computed tomography screening for lung cancer

Prediction of subsolid pulmonary nodule growth rate using radiomics

BACKGROUND

Pulmonary nodule growth rate assessment is critical in the management of subsolid pulmonary nodules (SSNs) during clinical follow-up. The present study aimed to develop a model to predict the growth rate of SSNs.

METHODS

A total of 273 growing SSNs with clinical information and 857 computed tomography (CT) scans were retrospectively analyzed. The images were randomly divided into training and validation sets. All images were categorized into fast-growth (volume doubling time (VDT) ≤ 400 days) and slow-growth (VDT > 400 days) groups. Models for predicting the growth rate of SSNs were developed using radiomics and clinical features. The models' performance was evaluated using the area under the curve (AUC) values for the receiver operating characteristic curve.

RESULTS

The fast- and slow-growth groups included 108 and 749 scans, respectively, and 10 radiomics features and three radiographic features (nodule density, presence of spiculation, and presence of vascular changes) were selected to predict the growth rate of SSNs. The nomogram integrating radiomics and radiographic features (AUC = 0.928 and AUC = 0.905, respectively) performed better than the radiographic (AUC = 0.668 and AUC = 0.689, respectively) and radiomics (AUC = 0.888 and AUC = 0.816, respectively) models alone in both the training and validation sets.

CONCLUSION

The nomogram model developed by combining radiomics with radiographic features can predict the growth rate of SSNs more accurately than traditional radiographic models. It can also optimize clinical treatment decisions for patients with SSNs and improve their long-term management.

Diagnostic Yield of Shape-Sensing Robotic-Assisted Bronchoscopy for Ground-Glass Nodules and Subsolid Nodules with a Solid Component Less than 6 mm

BACKGROUND

Ground-glass pulmonary nodules (GGNs) are most commonly sampled by percutaneous transthoracic biopsy. Diagnostic yield for ground-glass nodules using robotic-assisted bronchoscopy has been scarcely described, with a reported yield of 70.6%.

OBJECTIVES

The aim of this study is to assess diagnostic yield for GGNs using shape-sensing robotic-assisted bronchoscopy (ssRAB).

METHOD

A retrospective study of patients who underwent ssRAB for evaluation of GGNs, from September 2021 to April 2023. Primary outcome was diagnostic yield of ssRAB for GGNs, secondary outcomes were sensitivity for malignancy, and complications that required admission or intervention.

RESULTS

A total of 23 nodules were biopsied from 22 patients. Median age was 71 years (IQR 66-81), 63.6% were female, and 40.9% had a previous history of cancer. Forty-three percent of nodules were in the right upper lobes, and the median lesion size was 1.8 × 1.21. Twelve were subsolid nodules (SSNs), and 11 were pure GGNs. Overall diagnostic yield was 87%, with a sensitivity for malignancy of 88.9%. Adenocarcinoma was the most common malignancy diagnosed (70%). No procedure-related complications were reported.

CONCLUSION

The use of ssRAB shows a high diagnostic yield for diagnosing GGN and SSN with less than 6 mm solid component with a low risk for complications.

Solitary Pulmonary Nodule Evaluation: Pearls and Pitfalls

Lung nodules are frequently encountered while interpreting chest CTs and are challenging to detect, characterize, and manage given they can represent both benign or malignant etiologies. An understanding of features associated with malignancy and causes of interpretive pitfalls is helpful to avoid misdiagnoses. This review addresses pertinent topics related to the etiologies for missed lung nodules on radiography and CT. Additionally, CT imaging technical pitfalls and challenges in addition to issues in the evaluation of nodule morphology, attenuation, and size will be discussed. Nodule management guidelines will be addressed as well as recent investigations that further our understanding of lung nodules.

Deep sequencing reveals the genomic characteristics of lung adenocarcinoma presenting as ground-glass nodules (GGNs)

Background

The concept of multi-step progression from atypical adenomatous hyperplasia (AAH) to invasive adenocarcinoma (ADC) has been proposed, and ground-glass nodules (GGNs) may play a critical role during the early lung tumorigenesis. We present the first comprehensive description of the genomic architecture of GGNs to unravel the genetic basis of GGN.

Methods

We investigated 30 GGN-like lungs ADC by performing >1,000× whole-exome sequencing (WES) and characterized the genomic variations and evaluate the relationship between the clinicopathologic and molecular characteristics in this disease.

Results

Despite the low somatic mutation burden, GGNs exhibited high intratumor heterogeneity (ITH) characterized by the proportion of subclonal mutations. Different mutagenesis shaped the genomes of GGN during cancer evolution and were mostly featured by molecular clock-like signatures that occur in clonal mutations and defective DNA mismatch signatures that occur in subclonal mutations. Moreover, 10.7–67.1% clonal mutations occurred after whole-genome doubling (WGD), indicating that WGD could be a frequent truncal event in GGNs. Samples with WGD showed higher genomic instability but lower ITH. These GGNs were characterized by recurrent focal copy-number changes that are highly associated with tumorigenesis, with only two genes (EGFR and RBM10) that were recurrently mutated. Additionally, GGNs with different pathological subtypes or computed tomography (CT) features exhibited distinct genetic characteristics. Lepidic predominant or pure GGNs in CT images carried a lower mutation burden and had a relatively stable genome than nonlepidic or mixed GGNs. GGNs with RBM10 mutations tended to accompany a pathologically lepidic pattern, indicating RBM10 may drive the distinct subtype of lung cancer with better prognosis.

Conclusions

These findings facilitated interpreting the genomic characteristics of GGNs, provided insight into the early stages of lung cancer evolution, and possessed potential clinical significance.

Lung-RADS Version 1.1: Challenges and a Look Ahead, From the AJR Special Series on Radiology Reporting and Data Systems

In 2014, the American College of Radiology (ACR) created Lung-RADS 1.0. The system was updated to Lung-RADS 1.1 in 2019, and further updates are anticipated as additional data become available. Lung-RADS provides a common lexicon and standardized nodule follow-up management paradigm for use when reporting lung cancer screening (LCS) low-dose CT (LDCT) chest examinations and serves as a quality assurance and outcome monitoring tool. The use of Lung-RADS is intended to improve LCS performance and lead to better patient outcomes. To date, the ACR's Lung Cancer Screening Registry is the only LCS registry approved by the Centers for Medicare & Medicaid Services and requires the use of Lung-RADS categories for reimbursement. Numerous challenges have emerged regarding the use of Lung-RADS in clinical practice, including the timing of return to LCS after planned follow-up diagnostic evaluation; potential substitution of interval diagnostic CT for future LDCT; role of volumetric analysis in assessing nodule size; assessment of nodule growth; assessment of cavitary, subpleural, and category 4X nodules; and variability in reporting of the S modifier. This article highlights the major updates between versions 1.0 and 1.1 of Lung-RADS, describes the system's ongoing challenges, and summarizes current evidence and recommendations.

Medical Imaging Engineering and Technology Branch of the Chinese Society of Biomedical Engineering expert consensus on the application of Emergency Mobile Cabin CT

Started during December 2019, following the emergence of several COVID-19 cases in Wuhan City, Hubei Province, there was a rapid surge and spread of new COVID-19 cases throughout China. The disease has since been included in the Class B infectious diseases category, as stipulated in the Law of the People's Republic of China on the Prevention and Treatment of Infectious Diseases and shall be managed according to Class A infectious diseases. During the early phases of COVID-19 infection, no specific pulmonary imaging features may be evident, or features overlapping with other pneumonia may be observed. Although CT is not the gold standard for the diagnosis of COVID-19, it nonetheless is a convenient and fast method, and its application can be deployed in community hospitals. Furthermore, CT can be used to render a suggestive diagnosis and evaluate the severity as well as the effects of therapeutic interventions for typical cases of COVID-19. The mobile emergency special CT device described in this document (also known as Emergency Mobile Cabin CT) has several unique characteristics, including its mobility, flexibility, and networking capabilities. Furthermore, it adopts a fully independent isolation design to avoid cross-infection between patients and medical staff. It can play an important role in screening suspected cases presenting with imaging features of COVID-19 in hospitals of various levels that provide care to suspected or confirmed COVID-19 patients as part of the first line procedures of epidemic prevention and control.

The Growth Trend Predictions in Pulmonary Ground Glass Nodules Based on Radiomic CT Features

Background: The management of ground glass nodules (GGNs) remains a distinctive challenge. This study is aimed at comparing the predictive growth trends of radiomic features against current clinical features for the evaluation of GGNs.

Methods: A total of 110 GGNs in 85 patients were included in this retrospective study, in which follow up occurred over a span ≥2 years. A total of 396 radiomic features were manually segmented by radiologists and quantitatively analyzed using an Analysis Kit software. After feature selection, three models were developed to predict the growth of GGNs. The performance of all three models was evaluated by a receiver operating characteristic (ROC) curve. The best performing model was also assessed by calibration and clinical utility.

Results: After using a stepwise multivariate logistic regression analysis and dimensionality reduction, the diameter and five specific radiomic features were included in the clinical model and the radiomic model. The rad-score [odds ratio (OR) = 5.130; P < 0.01] and diameter (OR = 1.087; P < 0.05) were both considered as predictive indicators for the growth of GGNs. Meanwhile, the area under the ROC curve of the combined model reached 0.801. The high degree of fitting and favorable clinical utility was detected using the calibration curve with the Hosmer-Lemeshow test and the decision curve analysis was utilized for the nomogram.

Conclusions: A combined model using the current clinical features alongside the radiomic features can serve as a powerful tool to assist clinicians in guiding the management of GGNs.

Shades of Gray: Subsolid Nodule Considerations and Management

Subsolid nodules are common on chest CT imaging and may be either benign or malignant. Their varied features and broad differential diagnoses present management challenges. Although subsolid nodules often represent lung adenocarcinomas, other possibilities are common and influence management. Practice guidelines exist for subsolid nodule management for both incidentally and screening-detected nodules, incorporating patient and nodule characteristics. This review highlights the similarities and differences among these algorithms, with the intent of providing a resource for comparison and aid in choosing management options.

Prediction of tumor doubling time of lung adenocarcinoma using radiomic margin characteristics

Background

Because shape or irregularity along the tumor perimeter can result from interactions between the tumor and the surrounding parenchyma, there could be a difference in tumor growth rate according to tumor margin or shape. However, no attempt has been made to evaluate the correlation between margin or shape features and tumor growth.

Methods

We evaluated 52 lung adenocarcinoma (ADC) patients who had at least two computed tomographic (CT) examinations before curative resection. Volume‐based doubling times (DTs) were calculated based on CT scans, and patients were divided into two groups according to the growth pattern (GP) of their ADCs (gradually growing tumors [GP I] vs. growing tumors with a temporary decrease in DT [GP II]). CT radiomic features reflecting margin characteristics were extracted, and radiomic features reflective of tumor DT were selected.

Results

Among the 52 patients, 41 (78.8%) were assigned to GP I and 11 (21.2%) to GP II. Of the 94 radiomic features extracted, eccentricity, surface‐to‐volume ratio, LoG uniformity (σ = 3.5), and LoG skewness (σ = 0.5) were ultimately selected for tumor DT prediction. Selected radiomic features in GP I were surface‐to‐volume ratio, contrast, LoG uniformity (σ = 3.5), and LoG skewness (σ = 0.5), similar to those for total subjects, whereas the radiomic features in GP II were solidity, energy, and busyness.

Conclusions

This study demonstrated the potential of margin‐related radiomic features to predict tumor DT in lung ADCs.

Key points

Significant findings of the study

We found a relationship between margin‐related radiomic features and tumor doubling time.

What this study adds

Margin‐related radiomic features can potentially be used as noninvasive biomarkers to predict tumor doubling time in lung adenocarcinoma and inform treatment strategies.

Stepwise Disease Progression Model of Subsolid Lung Adenocarcinoma with Cystic Airspaces

OBJECTIVES

Subsolid lung adenocarcinoma with cystic airspaces (LACA) is a unique manifestation of lung cancer. This study was conducted to establish a radiologic disease progression model of LACA and to explore its association with the clinical course and clinicopathologic features of LACA.

MATERIALS AND METHODS

Sixty patients with LACA who underwent surgery at our center between 2004 and 2017 were retrospectively reviewed. The morphological changes of LACA over time on 98 serial computed tomography scans from 27 of 60 patients were tracked to establish a radiologic disease progression model. Associations between this model and the clinicopathologic characteristics of LACA were investigated.

RESULTS

The following stepwise progression model of LACA was developed: in phase I, cystic airspaces (CAs) appear in the middle of non-solid nodules; in phase II, the CAs grow; in phase III, a solid component appears on the border of the CAs; and in phase IV, the solid component gradually surrounds the CAs and becomes thicker, and the CAs shrink. In total, 10 (17%), 33 (55%), and 17 (28%) LACA patients were classified as belonging to phases II, III, and IV at the time of surgery, respectively. More advanced phases were associated with higher pathologic T and N staging, lymphovascular invasion, visceral pleural invasion, spread through air spaces, and solid/micropapillary subtype. In the multivariate analysis, our model demonstrated a good discrimination capability for cancer recurrence risk.

CONCLUSIONS

The stepwise disease progression model of LACA based on radiologic findings developed in this study represented its natural clinical course and clinicopathologic features well.

The Natural Growth of Subsolid Nodules Predicted by Quantitative Initial CT Features: A Systematic Review

Background: The detection rate for pulmonary nodules, particularly subsolid nodules (SSNs), has been significantly improved. The purpose of this review is to summarize the relationship between quantitative features of initial CT imaging and the subsequent natural growth of SSNs to explore potential reasons for these findings.

Methods: Relevant studies were collected from a literature search of PubMed, Embase, Web of Science, and Cochrane. Data extraction was performed on the patients' basic information, CT methods, and acquisition methods, including quantitative CT features, and statistical methods.

Results: A total of 10 relevant articles were included in our review, which included 850 patients with 1,026 SSNs. Overall, the results were variable, and the key findings were as follows. Seven studies looked at the relationship between the diameter and growth of SSNs, showing that SSNs with larger diameters were associated with increased growth. An additional three studies which focused on the relationship between CT attenuation and the growth of SSNs showed that SSNs with a high CT attenuation were associated with increased growth.

Conclusion: CT attenuation may be useful in predicting the natural growth of SSNs, and mean CT attenuation may be more useful in predicting the natural growth of pure ground glass nodules (GGNs) than part-solid GGNs. While evaluation by diameter did have some limitations, it demonstrates value in predicting the growth of SSNs.

The Prognostic Significance of Pure Ground Glass Opacities in Lung Cancer Computed Tomographic Images

Objective: Pure ground-glass opacity (GGO) nodules have been detected with increasing frequency using computed tomography (CT). We performed a retrospective study to clarify whether lung cancer patient prognoses correlated with pure GGO nodules. We also analyzed the clinical characters of patients with pure GGO nodules to provide diagnostic guidance on lung cancer identification and treatment of patients in clinical practice.

Methods: We enrolled 39 of 1422 patients with pure GGO nodules who accepted surgical treatment of the lung cancer nodules, and reviewed materials from 404 patients to verify our conclusions. To discover which factors were prognostically significant, we used the Kaplan-Meier method to estimate the overall survival (OS) and progression-free survival (PFS) curves. Age, gender, smoking history, histology, tumor size, and stage were the factors examined in our study. We also performed subgroup and matching group analyses to clarify the correlation between the presence of pure GGO nodules and prognoses.

Results: Pure GGO nodules were associated with non-smoking females that had adenocarcinoma. The prognoses of patients in the pure GGO nodule group was better than those in the non-pure GGO nodule group (p = 0.046). Age, grade, and stage (including tumor size and lymph node metastases) were had prognostic significance. In the matching group stage assessments, although patient prognoses were not significantly different among patients of the GGO group compared with thoses of the other group in long-term, while in the short term, patients with pure GGO nodules had longer PFS. Non-smoking female patients with lung cancer were more likely to have adenocarcinoma.

Conclusions: As a subgroup of GGO nodules, pure GGO nodules predict a better prognosis in all lung cancer patients. Wheras our study showed that lung patients with pure GGO nodules in similar stages were not significantly different in long-term prognoses, in the short term; patients with pure GGO nodules had longer PFS.

Importance of avoiding surgery delays after initial discovery of suspected non-small-cell lung cancer in clinical stage IA patients

Introduction

The natural history of consolidation on computed tomography (CT) rarely includes invasive cancers, and evidence of the ideal timing for surgical intervention via long-term follow-up studies remains unknown.

Methods

Between January 2012 and June 2017, pulmonary resection was undertaken in 293 clinical IA patients who were followed-up for > 6 months after the first detection of potential non-small-cell lung cancer (NSCLC) opacities. We evaluated the corresponding HRs and compared the recurrence risk with the CT follow-up duration.

Results

HRs calculated for the longest intervals were compared between two patient subsets: a shorter-interval surgery group (SISG: 41.3%; mean follow-up interval, 13.5±5.3 months) and a longer-interval surgery group (58.7%; mean follow-up interval, 54.9±25.6 months). On Cox multivariate regression analyses, CT consolidation (ratio >0.5), an abnormal carcinoembryonic antigen and a triple-negative mutation showed an independent association with an unfavorable prognosis, as measured by disease-free survival after the first detection of potential NSCLC opacities. The longer-interval surgery group fared significantly better than the SISG in terms of 5-year overall survival after the first detection (99.3% vs 93.1%, P<0.01); the 3-year overall survival after the first detection was significantly shorter in the high-risk SISG (presence of two factors from the three) than that in the low-risk SISG (presence of 0 or one factor; 100% vs 73.3%, P<0.01).

Conclusion

Our study indicates that the patients with potential NSCLC opacities who are able to wait for more than 2 years prior to pulmonary resection may be likely to have a favorable prognosis, whereas early judgment for surgical resection should be required for avoiding surgical delays.

Computed tomography and pathology evaluation of lung ground-glass opacity

The aim of this study was to investigate the pathogenesis of lung ground-glass opacity (GGO) and the diagnostic value of computed tomography scan for lung GGO. Computed tomography (CT) images of 106 lung GGO cases were analyzed retrospectively, and the type, location, size, structure, boundaries and surrounding lung fields were evaluated. There were 12 cases of GGO with a diameter <1.0 cm, 36 cases with diameter of 1.0-1.5 cm, 25 cases with diameter of 1.6-2.0 cm, 19 cases with diameter of 2.0-2.5 cm and 14 cases with diameter of 2.5-3.0 cm. There were 20 lesions with a round shape and 68 lesions with an oval shape. There were 56 lesions with spinous processes, 18 lesions with air bronchograms and 37 lesions with surrounding pleural indentation. The diagnosis and differential diagnosis of GGO would be improved with combined CT scan and pathology results.

From focal pulmonary pure ground-glass opacity nodule detected by low-dose computed tomography into invasive lung adenocarcinoma: A growth pattern analysis in the elderly

Background

Elderly patients are under‐represented in studies of pure ground‐glass opacity (pGGO) nodules; thus, this study analyzed the growth pattern and clinical outcomes of pGGO nodules in the elderly in order to help make treatment decisions.

Methods

We retrospectively reviewed patients aged over 60 years with screening‐detected and pathologically confirmed growing focal pGGO nodules.

Results

During the study period, 858 subjects had undergone at least three low‐dose computed tomography scans in our center. Twenty patients were treated for growing focal pGGO nodules. The median age at detection was 66 years (range: 60–80). The median time to an increase of at least 2 mm was 348 days (range: 98–1527) and to develop a solid portion, 1141 days (range: 480–3010). Seven patients had surgery for increased nodule size, four had surgery immediately after the solid portion appeared, and nine were treated after a median follow‐up of 1153 days (range: 240–2342) since the solid portion developed. The median size of the solid component was 8 mm (2–13) before surgery. No recurrence was observed after a median follow‐up of 41 months. Pathology revealed adenocarcinoma in situ in five patients, and minimally invasive or invasive adenocarcinoma in the remainder. The appearance of a solid portion was significantly associated with invasive adenocarcinoma compared to increased size alone (100% vs. 44.4%; P = 0.005).

Conclusions

pGGO nodules had an indolent growth pattern and good prognosis in our patient sample, even after the appearance of a solid portion. Therefore, minimally invasive surgery after the development of a solid component may be an option for the elderly.

Are there any metastases to the chest in non-muscle-invasive bladder cancer patients on follow-up computed tomography?

PURPOSE

The purpose of the study was to retrospectively determine whether there are metastases to the chest in patients with primary non-muscle-invasive urothelial carcinoma in the bladder on the follow-up computed tomography (CT).

METHODS

We analyzed 328 patients with follow-up chest CT for urothelial carcinoma of the bladder diagnosed between January 2004 and September 2013. We divided patients into four groups: Ta (n = 74), T1 (n = 78), carcinoma in situ (CIS, n = 25), and ≥ T2 (n = 151). We used the chest CT to determine whether there were positive findings of metastasis. Univariate and multivariate analyses were achieved using categories of T stage, histological grade, multifocal lesions, and recurrence.

RESULTS

On univariate analysis, there were significant differences on T stage (p < 0.001) and histological grade (p = 0.001), and there was no significant difference on multifocal lesions (p = 0.11) and recurrence (p = 0.34). Positive findings of metastases were observed in 1.4% (1/74) of the Ta patients, 0% (0/78) of the T1 patients, 8.0% (2/25) of the patients with carcinoma in situ (CIS), and 27.2% (41/151) of the ≥ T2 patients (p < 0.001). On multivariate analysis, T staging was independent variable for positive findings of metastasis (Odds ratio; 2.84, 95% Confidence Interval; 1.65-4.89). In contrast, histological grade, multifocal lesions, and recurrence were not independent variables.

CONCLUSIONS

T stage would affect to metastasis to the chest. It might be appropriate to omit chest CT in patients with Ta or T1 without upstaging in the course of follow-up. We may suggest that the follow-up chest CT in patients with CIS.

Management of Incidental Lung Nodules

The incidental pulmonary nodule is commonly encountered when interpreting chest CTs. The management of pulmonary nodules requires a multidisciplinary approach entailing integration of nodule size and features, clinical risk factors, and patient preference and comorbidities. Guidelines have been issued for the management of both solid and subsolid nodules, with the Fleischner Society issuing revised guidelines in 2017. This article focuses on the CT imaging characteristics and clinical behavior of pulmonary nodules, with review of the current management guidelines that reflect this knowledge.

[Growth Evaluation of Pulmonary Nodules on Chest CT]

对肺结节行计算机断层扫描（computed tomography, CT）随访并确定结节生长特性是临床针对不定性肺结节常采用的策略。依据肿瘤生长指数模型，常采用体积或质量倍增时间量化结节的生长速率。本文拟对肺癌的指数生长模型、肺结节生长量化评价的方法学、不同类型肺结节的生长特性进行综述。

Lung adenocarcinomas: correlation of computed tomography and pathology findings

Adenocarcinoma is the most common histologic type of lung cancer. Recent lung adenocarcinoma classifications from the International Association for the Study of Lung cancer, the American Thoracic Society and the European Respiratory Society (IASLC/ETS/ERS, 2011) and World Health Organization (WHO, 2015) define a wide range of adenocarcinoma types and subtypes featuring different prognosis and management. This spectrum of lesions translates into various CT presentations and features, which generally show good correlation with histopathology, stressing the key role of the radiologist in the diagnosis and management of those patients. This review aims at helping radiologists to understand the basics of the up-to-date adenocarcinoma pathological classifications, radio-pathological correlations and how to use them in the clinical setting, as well as other imaging-related correlations (radiogenomics, quantitative analysis, PET-CT).

Epidermal growth factor receptor mutations in adenocarcinoma in situ and minimally invasive adenocarcinoma detected using mutation-specific monoclonal antibodies

OBJECTIVES

Epidermal growth factor receptor (EGFR) mutation rates in adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) were studied using both DNA analysis and mutation-specific immunohistochemistry.

MATERIALS AND METHODS

The peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method was used to detect mutations in exons 18, 19, 20, and 21 of the EGFR gene in DNA samples extracted from paraffin-embedded tissue sections. Simultaneously, immunohistochemical analysis with two EGFR mutation-specific monoclonal antibodies was used to identify proteins resulting from an in-frame deletion in exon 19 (E746_A750del) and a point mutation replacing leucine with arginine at codon 858 of exon 21 (L858R).

RESULTS

Forty-three tumors (22 AIS and 21 MIA) were examined. The EGFR mutation rate in AIS detected by DNA analysis was 27.3% (L858R, 5/22; exon 19 deletion,1/22), whereas that detected in MIA was 42.9% (L858R,4/21; exon 19 deletion,5/21). Mutations detected by immunohistochemical analysis included 22.7% (L858R, 4/22; exon 19 deletion, 1/22) in AIS and 42.9% (L858R, 4/21; exon 19 deletion, 5/21) in MIA. Although some results were contradictory, concordant results were obtained using both assays in 38 of 43 cases (88.4%).

CONCLUSION

DNA and immunohistochemical analyses revealed similar EGFR mutation rates in both MIA and AIS, suggesting that mutation-specific monoclonal antibodies are useful to confirm DNA assay results.

Lung Cancer Deaths in the National Lung Screening Trial Attributed to Nonsolid Nodules

Purpose To validate the recommendation of performing annual follow-up of nonsolid nodules (NSNs) identified by computed tomographic (CT) screening for lung cancer, all cases of lung cancer manifesting as NSN in the National Lung Screening Trial (NLST) were reviewed. Materials and Methods Institutional review board and informed consent were waived for this study. The NLST database was searched to identify all participants with at least one NSN on CT scan with lung cancer as the cause of death (COD) documented by the NLST endpoint verification process. Among the 26 722 participants, 2534 (9.4%) had one or more NSNs, and lung cancer as the COD occurred for 48 participants. On review, 21 of the 48 patients had no NSN in the cancerous lobe, which left 27 patients whose CT scans were reviewed by four radiologists: Group A (n = 12) were cases of lung cancer as the COD because of adenocarcinoma, and group B (n = 15) were cases of lung cancer as the COD because of other cell types. Frequency of lung cancer as the COD because of NSN and the time from randomization to diagnosis within these groups was determined. Results Six of the 12 patients in group A had no NSN in the cancerous lobe whereas the remaining six patients had a dominant solid or part-solid nodule in the lobe that rapidly grew in four patients, was multifocal in one patient, and had a growing NSN in one patient in whom diagnosis was delayed for over 3 years. Five of the 15 patients in group B had no NSN, and for the remaining 10 patients, lung cancer as the COD was not because of NSN. Conclusion It seems unlikely that patients with lung cancer as the COD occurred with solitary or dominant NSN as long as annual follow-up was performed. This lends further support that lung cancers that manifest as NSNs have an indolent course and can be managed with annual follow-up. ^© RSNA, 2016.

Natural History of Pulmonary Subsolid Nodules: A Prospective Multicenter Study

INTRODUCTION

The purpose of this study was to evaluate the natural course of the progression of pulmonary subsolid nodules (SSNs).

MATERIALS AND METHODS

Eight facilities participated in this study. A total of 795 patients with 1229 SSNs were assessed for the frequency of invasive adenocarcinomas. SSNs were classified into three categories: pure ground-glass nodules (PGGNs), heterogeneous GGNs (HGGNs) (solid component detected only in lung windows), and part-solid nodules.

RESULTS

The mean prospective follow-up period was 4.3 ± 2.5 years. SSNs were classified at baseline as follows: 1046 PGGNs, 81 HGGNs, and 102 part-solid nodules. Among the 1046 PGGNs, 13 (1.2%) developed into HGGNs and 56 (5.4%) developed into part-solid nodules. Among the 81 HGGNs, 16 (19.8%) developed into part-solid nodules. Thus, the SSNs at the final follow-up were classified as follows: 977 PGGNs, 78 HGGNs, and 174 part-solid nodules. Of the 977 PGGNs, 35 were resected (nine minimally invasive adenocarcinomas [MIAs], 21 adenocarcinomas in situ [AIS], and five atypical adenomatous hyperplasias). Of the 78 HGGNs, seven were resected (five MIAs and two AIS). Of the 174 part-solid nodules, 49 were resected (12 invasive adenocarcinomas, 26 MIAs, 10 AIS, and one adenomatous hyperplasia). For the PGGNs, the mean period until their development into part-solid nodules was 3.8 ± 2.0 years, whereas the mean period for the HGGNs was 2.1 ± 2.3 years (p = 0.0004).

CONCLUSION

This study revealed the frequencies and periods of development from PGGNs and HGGNs into part-solid nodules. Invasive adenocarcinomas were diagnosed only among the part-solid nodules, corresponding to 1% of all 1229 SSNs.

Pulmonary ground-glass nodules diagnosis: mean change rate of peak CT number as a discriminative factor of pathology during a follow-up

OBJECTIVE

We aimed to analyse the peak CT number (PEAK) in CT number histogram of ground-glass nodules (GGN), meaning the most frequent density of pixels in the image of pulmonary nodule, based on three-dimensional (3D) reconstructive model pre-operatively, and the mean rate of PEAK change (V-PEAK) during a follow-up of GGN for differential diagnosis between pre-invasive adenocarcinoma (PIA) and invasive adenocarcinoma (IAC).

METHODS

CT number histogram of pixels in GGN was made automatically by 3D measurement software. Diameter, total volume, PEAK and V-PEAK were measured from CT data sets of different groups classified by pathology, subtype and number of GGN, respectively.

RESULTS

Among all 102 cases, 47 were PIA, including atypical adenomatous hyperplasia (n = 29) and adenocarcinoma in situ (n = 18), and 55 were IAC, including minimally IAC (MIA, n = 4). By Wilcoxon test, PEAK of IAC was significantly higher than that of PIA (p < 0.001). By receiver operating curve analysis, area under the curve (AUC) was 0.857 and threshold -820.50 Hounsfield units (HU) for differentiation between PIA and IAC. V-PEAK of IAC was unexpectedly remarkably smaller than that of PIA (p < 0.001) with AUC and threshold being 0.810 and -0.829 HU day(-1), respectively.

CONCLUSION

Pre-operative PEAK and V-PEAK, which interpret and evaluate the change of volume and density of pulmonary nodule simultaneously from both exterior and interior perspectives, can help to distinguish IAC from PIA.

ADVANCES IN KNOWLEDGE

This study provided researchers of GGN another perspective, taking both volume and density of nodules into consideration for pathological evaluation.

Correlation between histological invasiveness and the computed tomography value in pure ground-glass nodules

Purpose

The purpose of this study was to evaluate the correlation between histological invasiveness and the computed tomography (CT) value and size in pure ground-glass nodules (GGNs) to determine optimal “follow-up or resection” strategies.

Methods

Between 2001 and 2014, 78 resected, pure GGNs were retrospectively evaluated. The maximum diameter and CT value of pure GGNs were measured using a computer graphics support system.

Results

All GGNs with a maximum diameter ≤10 mm and CT value ≤−600 Hounsfield units (HU) were considered to be noninvasive lesions, while 21 of 26 (81 %) with a maximum diameter >10 mm and CT value >−600 HU were considered to be invasive lesions. With respect to the correlation between each histological type and pure GGN with a maximum diameter ≤10 mm and CT value ≤−600 HU, the specificity was 90 % and the sensitivity and negative predictive value were both 100 % in atypical adenomatous hyperplasia (AAH), while the specificity was 58 % and the sensitivity and positive predictive value were 0 % in minimally invasive and invasive adenocarcinoma.

Conclusion

Pure GGNs with a maximum diameter of ≤10 mm and CT value of ≤−600 HU are nearly always pre-invasive lesions; therefore, surgery should be carefully selected in such patients.

Preoperative Prediction of Ki-67 Labeling Index By Three-dimensional CT Image Parameters for Differential Diagnosis Of Ground-Glass Opacity (GGO)

The aim of this study was to predict Ki-67 labeling index (LI) preoperatively by three-dimensional (3D) CT image parameters for pathologic assessment of GGO nodules. Diameter, total volume (TV), the maximum CT number (MAX), average CT number (AVG) and standard deviation of CT number within the whole GGO nodule (STD) were measured by 3D CT workstation. By detection of immunohistochemistry and Image Software Pro Plus 6.0, different Ki-67 LI were measured and statistically analyzed among preinvasive adenocarcinoma (PIA), minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC). Receiver operating characteristic (ROC) curve, Spearman correlation analysis and multiple linear regression analysis with cross-validation were performed to further research a quantitative correlation between Ki-67 labeling index and radiological parameters. Diameter, TV, MAX, AVG and STD increased along with PIA, MIA and IAC significantly and consecutively. In the multiple linear regression model by a stepwise way, we obtained an equation: prediction of Ki-67 LI=0.022*STD+0.001* TV+2.137 (R=0.595, R’s square=0.354, p<0.001), which can predict Ki-67 LI as a proliferative marker preoperatively. Diameter, TV, MAX, AVG and STD could discriminate pathologic categories of GGO nodules significantly. Ki-67 LI of early lung adenocarcinoma presenting GGO can be predicted by radiologic parameters based on 3D CT for differential diagnosis.

Pulmonary subsolid nodules: what radiologists need to know about the imaging features and management strategy

Pulmonary subsolid nodules (SSNs) refer to pulmonary nodules with pure ground-glass nodules and part-solid ground-glass nodules. SSNs are frequently encountered in the clinical setting, such as screening chest computed tomography (CT). The main concern regarding pulmonary SSNs, particularly when they are persistent, has been lung adenocarcinoma and its precursors. The CT manifestations of SSNs help radiologists and clinicians manage these lesions. However, the management plan for SSNs has not previously been standardized. Recently, the Fleischner Society published recommendations for the management of incidentally detected SSNs. The guidelines reflect the new lung adenocarcinoma classification system proposed by the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society (IASLC/ATS/ERS) and include six specific recommendations according to the nodule size, solid portion and multiplicity. This review aims to increase the understanding of SSNs and the imaging features of SSNs according to their histology, natural course, possible radiologic interventions, such as biopsy, localization prior to surgery, and current management.

Imaging the solitary pulmonary nodule

The development of widespread lung cancer screening programs has the potential to dramatically increase the number of thoracic computed tomography (CT) examinations performed annually in the United States, resulting in a greater number of newly detected, indeterminate solitary pulmonary nodules (SPNs). Additional imaging studies, such as fluorodeoxyglucose F 18 (FDG)-positron emission tomography (PET), have been shown to provide valuable information in the assessment of indeterminate SPNs. Newer technologies, such as contrast-enhanced dual-energy chest CT and FDG-PET/CT, also have the potential to facilitate diagnosis of potentially malignant SPNs.

Outcomes of unresected ground-glass nodules with cytology suspicious for adenocarcinoma

BACKGROUND

Five-year survival rates for resected stage I adenocarcinoma approach 100%. Given previous studies describing the prolonged indolent natural history of ground-glass lesions suspicious for early adenocarcinoma, our purpose in this study was to determine if outcomes were different among patients who were observed for radiographic and biopsy suspected early adenocarcinoma compared with those who were resected immediately.

METHODS

We identified 63 patients with no prior history of lung adenocarcinoma who had undergone computer tomography-guided fine-needle aspiration of ground-glass opacities with cytology concerning for new early adenocarcinoma between January 2002 and December 2011. We compared the clinical outcomes of patients who were resected after abnormal cytology results and those who opted for watchful waiting.

RESULTS

Sixteen patients elected to observe their ground-glass nodules despite having suspicious cytology results, whereas 47 opted for immediate resection. Of the 16 observed patients, six (37.5%) ultimately demonstrated growth or increase solid component of the ground-glass nodule. Five of these patients elected for definitive therapy by surgical resection or radiation. There were no occurrences of distant metastasis or lung cancer-associated deaths in the observed group. Of the 47 resected patients, two developed metastatic disease, five developed new cancers in remaining lung, and three developed progression in existing ground-glass nodules.

CONCLUSIONS

Ground-glass lesions that were observed after biopsy did not demonstrate any increased rates of metastasis or cancer-related deaths and delayed resection does not seem to have a negative effect on outcomes.

Evidence based imaging strategies for solitary pulmonary nodule

Solitary pulmonary nodule (SPN) is defined as a rounded opacity ≤3 cm in diameter surrounded by lung parenchyma. The majority of smokers who undergo thin-section CT have SPNs, most of which are smaller than 7 mm. In the past, multiple follow-up examinations over a two-year period, including CT follow-up at 3, 6, 12, 18, and 24 months, were recommended when such nodules are detected incidentally. This policy increases radiation burden for the affected population. Nodule features such as shape, edge characteristics, cavitation, and location have not yet been found to be accurate for distinguishing benign from malignant nodules. When SPN is considered to be indeterminate in the initial exam, the risk factor of the patients should be evaluated, which includes patients' age and smoking history. The 2005 Fleischner Society guideline stated that at least 99% of all nodules 4 mm or smaller are benign; when nodule is 5-9 mm in diameter, the best strategy is surveillance. The timing of these control examinations varies according to the nodule size (4-6, or 6-8 mm) and the type of patients, specifically at low or high risk of malignancy concerned. Noncalcified nodules larger than 8 mm diameter bear a substantial risk of malignancy, additional options such as contrast material-enhanced CT, positron emission tomography (PET), percutaneous needle biopsy, and thoracoscopic resection or videoassisted thoracoscopic resection should be considered.

Screening for lung cancer with low-dose computed tomography: a review of current status

Screening using low-dose computed tomography (CT) represents an exciting new development in the struggle to improve outcomes for people with lung cancer. Randomised controlled evidence demonstrating a 20% relative lung cancer mortality benefit has led to endorsement of screening by several expert bodies in the US and funding by healthcare providers. Despite this pivotal result, many questions remain regarding technical and logistical aspects of screening, cost-effectiveness and generalizability to other settings. This review discusses the rationale behind screening, the results of on-going trials, potential harms of screening and current knowledge gaps.

Volume and mass doubling times of persistent pulmonary subsolid nodules detected in patients without known malignancy

PURPOSE

To evaluate volume doubling time (VDT) and mass doubling time (MDT) of persistent pulmonary subsolid nodules (SSNs) followed-up with low-dose (LD) computed tomography (CT) in patients without a history of malignancy.

MATERIALS AND METHODS

This retrospective institutional review board-approved study, with waiver of patient informed consent, included 97 SSNs in 97 patients (45 men, 52 women; median age, 58 years; range, 37-87 years) in whom at least two LD CT scans were obtained, with 3-month or longer follow-up interval and median follow-up of 633 days. SSNs were categorized into pure ground-glass nodules (GGNs) (group A), part-solid GGNs with solid components of 5 mm or smaller (group B), and part-solid GGNs with solid components larger than 5 mm (group C). Three-dimensional manual segmentation for all SSNs was performed on initial and latest follow-up LD CT scans; subsequently, VDTs and MDTs were calculated and were compared among groups by using Kruskal-Wallis test, followed by the Dunn procedure with Bonferroni correction for volume-growing SSNs and mass-growing SSNs.

RESULTS

Volume growth was thus: 12 of 63 SSNs (19%), group A; nine of 23 SSNs (39%), group B; and eight of 11 SSNs (73%), group C. Median VDT was thus: 1832.3 days (range, 1230.7-4537.3 days), group A; 1228.5 days (range, 934.7-4617.7 days), group B; and 759.0 days (range, 376.4-941.5 days), group C. Mass growth was thus: 17 of 63 SSNs (27%), group A; 11 of 23 SSNs (48%), group B; and nine of 11 SSNs (82%), group C. Median MDT was 1556.1 days (range, 642.5-3564.5 days) for group A, 1199.9 days (range, 838.6-2578.7 days) for group B, and 627.7 days (range, 340.0-921.2 days) for group C. Median VDTs and MDTs of groups A and B were significantly longer than those of group C (P < .01).

CONCLUSION

Pure GGNs and part-solid GGNs with solid components of 5 mm or smaller show significantly longer VDTs and MDTs than do part-solid GGNs with solid components larger than 5 mm. Online supplemental material is available for this article.

A decrease in the size of ground glass nodules may indicate the optimal timing for curative surgery

OBJECTIVES

Although ground glass nodules (GGNs) are generally considered to grow slowly to a large size, their natural progression remains unclear, and a decrease in tumor size has been reported in a few previous studies. The study aimed to retrospectively review the radiologic and pathological characteristics of resected ground glass nodules (GGNs) followed with chest computed tomography (CT) for at least a year before surgery to clarify the natural progression of GGNs.

PATIENTS AND METHODS

The chest CT cans and clinical charts of 32 GGNs in 31 patients who underwent pulmonary resection between January 2006 and March 2013 were retrospectively reviewed. The definitions of pure GGNs and part-solid nodules were based on the tumor shadow disappearance rate. The tumor size was measured twice, and the mean size was used for evaluation.

RESULTS

The mean GGN size before surgery was 15.2 mm, and the median follow-up period before surgery was 21 months. In the follow-up period, 15 (58%) of 26 pure GGNs at the initial CT remained pure GGNs at the last CT. However, a solid component appeared in the remaining 11 tumors (42%) of the 26 initial pure GGNs. Furthermore, 1 GGN of the 15 GGNs that remained pure and 10 of the 11 GGNs with solid component also showed a size decrease. In addition, 6 part-solid nodules were observed at the initial CT. Of these, 3 showed a decrease in size during follow-up. Overall, 47% of the GGNs showed a size reduction on follow-up chest CT.

CONCLUSIONS

A size reduction was observed in nearly half of the GGNs and suggested the progression to an invasive adenocarcinoma. When a mild collapse of the GGNs is observed, a careful follow-up is necessary to identify a solid component. Tumor size decreases may represent the optimal timing of pulmonary resection for curative treatment.

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.

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.

Computed tomography quantitative analysis of components: a new method monitoring the growth of pulmonary nodule

BACKGROUND

The estimation of the growth of solitary pulmonary nodules by using non-invasive methods is increasingly gaining clinical importance for performing the timely adequate treatment of these nodules.

PURPOSE

To evaluate the application value of computed tomography (CT) quantitative analysis of components for dynamic assessment of the growth of solitary pulmonary nodules, and compare this approach with three-dimensional (3D) volumetric measurement of pulmonary nodules.

MATERIAL AND METHODS

The imaging data of 21 patients who had undergone multiple follow-up CT scans for solitary pulmonary nodules were retrospectively analyzed, and the total volume of pulmonary nodules and the percentage change in the total volume of pulmonary nodules after multiple follow-up CT scans were measured using 3D volume measurement software. The volume of solid components in pulmonary nodules was measured using CT quantitative analysis; the percentage change in the volume of solid components across examinations was calculated; and the percentage change in the total volume of pulmonary nodules was compared and contrasted with the percentage change in the volume of solid components in the pulmonary nodules.

RESULTS

All 21 cases were malignant adenocarcinomas. In the 21 cases of malignant nodules, the 3D volumes of the nodules and solid components were both increased, with the percentage change in the volume of the solid components (115.78-418.91%, 130.45 ± 119.48) significantly different from the percentage change in the total volume of the nodules (78.56-105.73% , 42.34 ± 32.17) (P = 0.02).

CONCLUSION

By measuring volume changes in solid components in the nodules, CT quantitative analysis offers more sensitive and earlier evaluation of the dynamic growth of the nodules than measurement of volume changes in the nodules alone.

Noninvasive characterization of the histopathologic features of pulmonary nodules of the lung adenocarcinoma spectrum using computer-aided nodule assessment and risk yield (CANARY)--a pilot study

INTRODUCTION

Pulmonary nodules of the adenocarcinoma spectrum are characterized by distinctive morphological and radiologic features and variable prognosis. Noninvasive high-resolution computed tomography-based risk stratification tools are needed to individualize their management.

METHODS

Radiologic measurements of histopathologic tissue invasion were developed in a training set of 54 pulmonary nodules of the adenocarcinoma spectrum and validated in 86 consecutively resected nodules. Nodules were isolated and characterized by computer-aided analysis, and data were analyzed by Spearman correlation, sensitivity, and specificity and the positive and negative predictive values.

RESULTS

Computer-aided nodule assessment and risk yield (CANARY) can noninvasively characterize pulmonary nodules of the adenocarcinoma spectrum. Unsupervised clustering analysis of high-resolution computed tomography data identified nine unique exemplars representing the basic radiologic building blocks of these lesions. The exemplar distribution within each nodule correlated well with the proportion of histologic tissue invasion, Spearman R = 0.87, p < 0.0001 and 0.89 and p < 0.0001 for the training and the validation set, respectively. Clustering of the exemplars in three-dimensional space corresponding to tissue invasion and lepidic growth was used to develop a CANARY decision algorithm that successfully categorized these pulmonary nodules as "aggressive" (invasive adenocarcinoma) or "indolent" (adenocarcinoma in situ and minimally invasive adenocarcinoma). Sensitivity, specificity, positive predictive value, and negative predictive value of this approach for the detection of aggressive lesions were 95.4, 96.8, 95.4, and 96.8%, respectively, in the training set and 98.7, 63.6, 94.9, and 87.5%, respectively, in the validation set.

CONCLUSION

CANARY represents a promising tool to noninvasively risk stratify pulmonary nodules of the adenocarcinoma spectrum.

The stage classification of lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

The current Lung Cancer Stage Classification system is the seventh edition, which took effect in January 2010. This article reviews the definitions for the TNM descriptors and the stage grouping in this system.

Special treatment issues in non-small cell lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

This guideline updates the second edition and addresses patients with particular forms of non-small cell lung cancer that require special considerations, including Pancoast tumors, T4 N0,1 M0 tumors, additional nodules in the same lobe (T3), ipsilateral different lobe (T4) or contralateral lung (M1a), synchronous and metachronous second primary lung cancers, solitary brain and adrenal metastases, and chest wall involvement.

METHODS

The nature of these special clinical cases is such that in most cases, meta-analyses or large prospective studies of patients are not available. To ensure that these guidelines were supported by the most current data available, publications appropriate to the topics covered in this article were obtained by performing a literature search of the MEDLINE computerized database. Where possible, we also reference other consensus opinion statements. Recommendations were developed by the writing committee, graded by a standardized method, and reviewed by all members of the Lung Cancer Guidelines panel prior to approval by the Thoracic Oncology NetWork, Guidelines Oversight Committee, and the Board of Regents of the American College of Chest Physicians.

RESULTS

In patients with a Pancoast tumor, a multimodality approach appears to be optimal, involving chemoradiotherapy and surgical resection, provided that appropriate staging has been carried out. Carefully selected patients with central T4 tumors that do not have mediastinal node involvement are uncommon, but surgical resection appears to be beneficial as part of their treatment rather than definitive chemoradiotherapy alone. Patients with lung cancer and an additional malignant nodule are difficult to categorize, and the current stage classification rules are ambiguous. Such patients should be evaluated by an experienced multidisciplinary team to determine whether the additional lesion represents a second primary lung cancer or an additional tumor nodule corresponding to the dominant cancer. Highly selected patients with a solitary focus of metastatic disease in the brain or adrenal gland appear to benefit from resection or stereotactic radiosurgery. This is particularly true in patients with a long disease-free interval. Finally, in patients with chest wall involvement, provided that the tumor can be completely resected and N2 nodal disease is absent, primary surgical resection should be considered.

CONCLUSIONS

Carefully selected patients with more uncommon presentations of lung cancer may benefit from an aggressive surgical approach.