Solitary and multiple resected adenocarcinomas after CT screening for lung cancer: histopathologic features and their prognostic implications

Long-Term Active Surveillance of Screening Detected Subsolid Nodules is a Safe Strategy to Reduce Overtreatment

INTRODUCTION

Lung cancer presenting as subsolid nodule (SSN) can show slow growth, hence treating SSN is controversial. Our aim was to determine the long-term outcome of subjects with unresected SSNs in lung cancer screening.

METHODS

Since 2005, the Multicenter Italian Lung Detection (MILD) screening trial implemented active surveillance for persistent SSN, as opposed to early resection. Presence of SSNs was related to diagnosis of cancer at the site of SSN, elsewhere in the lung, or in the body. The risk of overall mortality and lung cancer mortality was tested by Cox proportional hazards model.

RESULTS

SSNs were found in 16.9% (389 of 2303) of screenees. During 9.3 ± 1.2 years of follow-up, the hazard ratio of lung cancer diagnosis in subjects with SSN was 6.77 (95% confidence interval: 3.39-13.54), with 73% (22 of 30) of cancers not arising from SSN (median time to diagnosis 52 months from SSN). Lung cancer-specific mortality in subjects with SSN was significantly increased (hazard ratio = 3.80; 95% confidence interval: 1.24-11.65) compared to subjects without lung nodules. Lung cancer arising from SSN did not lead to death within the follow-up period.

CONCLUSIONS

Subjects with SSN in the MILD cohort showed a high risk of developing lung cancer elsewhere in the lung, with only a minority of cases arising from SSN, and never representing the cause of death. These results show the safety of active surveillance for conservative management of SSN until signs of solid component growth and the need for prolonged follow-up because of high risk of other cancers.

Clonality assessment of multifocal lung adenocarcinoma by pathology evaluation and molecular analysis

The aim of this study was to explore morphologic and molecular features distinguishing between multifocal lung adenocarcinoma (MLA) and intrapulmonary metastases (IMs). Sixteen patients with MLAs, a total of 34 tumors, were reviewed. Four approaches were used: (1) array-comparative genomic hybridization (CGH) as a standard clonality assessment; (2) EGFR and KRAS mutational profiles as a supplementary method; (3) comprehensive histologic assessment (CHA) was method I in pathology evaluation; and (4) CHA combined with lepidic component analysis was method II. The lepidic component was divided into low grade and high grade according to extent of atypia; tumors with low-grade lepidic component were defined as primary. Eight patients were found to have IMs and 8 to have multiple primaries (MPs) by array-CGH; 7 had MPs and 9 had IMs by method I; 5 had MPs and 11 had IMs by method II. Compared with array-CGH, method I had a lower coincidence rate (65%) than method II (85%). Univariate analysis revealed that patients with MP had a better clinical outcome than those with IM only if the MPs were diagnosed by array-CGH (P = .034) or method II (P = .027) but not EGFR/KRAS mutation (P = .843) or method I (P = .493). Our results suggest that a low-grade lepidic component is a sign of a primary tumor. CHA combined with a low-grade lepidic component (method II) is more accurate clinically and more cost-effective in distinguishing MLAs from IMs. Also, EGFR mutation is not an appropriate molecular marker for clonality assessment.

Diagnostic accuracy and complications of CT-guided core needle lung biopsy of solid and part-solid lesions

OBJECTIVE

To evaluate whether diagnostic accuracy and complications of CT-guided core needle biopsy (CNB) differ for solid and part-solid lung lesions Methods: This retrospective study included 354 consecutive patients from April 2012 to July 2016 who underwent CT-guided CNB of lung lesions by a radiologist. Patient demographics, lung lesions' characteristics; solid or part-solid, underlying pulmonary disease, distance of path, procedure time, complications (hemorrhage or pneumothorax), histopathological results of biopsy specimens and final diagnosis were reviewed. The diagnostic yields, biopsy-related factors and complications were compared for patients with solid lesions and patients with part-solid lesions. Factors related to true diagnoses and complications were analyzed statistically.

RESULTS

The biopsies of part-solid lesions take more time (p = 0.021). Non-diagnostic biopsies were not statistically different between solid and part-solid lesions (p = 0.804). There was no significant difference in the diagnostic yields including sensitivity, specificity, accuracy, positive predictive value and negative predictive value for solid and part-solid lesions statistically. The occurrence of hemorrhage on postbiopy follow-up CT was significantly higher (p = 0.016) for part-solid lesions. The occurrence of symptomatic major hemorrhage (p = 0.859) and pneumothorax (p = 0.106) was not significantly different between solid and part-solid lesions.

CONCLUSION

The diagnostic accuracy of CT-guided CNB for diagnosing malignancy was comparable for solid and part-solid lesions. The frequency of hemorrhage on the follow up CT was higher in patients with part-solid lesions, but there were no significant differences in major hemorrhage and pneumothorax for solid and part-solid lesions. Advances in knowledge: The diagnostic yield of CT-guided CNB for diagnosing malignancy is comparable for solid and part-solid lesions. Although the post procedural hemorrhage occurs more frequently in part-solid lesions, the occurrence of symptomatic major hemorrhage is not significantly different. Therefore, CT-guided CNB should be considered for histopathological confirmation of intrapulmonary lesions regardless of the presence of ground-glass opacity portion.

Visual discrimination of screen-detected persistent from transient subsolid nodules: An observer study

Purpose

To evaluate whether, and to which extent, experienced radiologists are able to visually correctly differentiate transient from persistent subsolid nodules from a single CT examination alone and to determine CT morphological features to make this differentiation.

Materials and methods

We selected 86 transient and 135 persistent subsolid nodules from the National Lung Screening Trial (NLST) database. Four experienced radiologists visually assessed a predefined list of morphological features and gave a final judgment on a continuous scale (0–100). To assess observer performance, area under the receiver operating characteristic (ROC) curve was calculated. Statistical differences of morphological features between transient and persistent lesions were calculated using Chi-square. Inter-observer agreement of morphological features was evaluated by percentage agreement.

Results

Forty-nine lesions were excluded by at least 2 observers, leaving 172 lesions for analysis. On average observers were able to differentiate transient from persistent subsolid nodules ≥ 10 mm with an area under the curve of 0.75 (95% CI 0.67–0.82). Nodule type, lesion margin, presence of a well-defined border, and pleural retraction showed significant differences between transient and persistent lesions in two observers. Average pair-wise percentage agreement for these features was 81%, 64%, 47% and 89% respectively. Agreement for other morphological features varied from 53% to 95%.

Conclusion

The visual capacity of experienced radiologists to differentiate persistent and transient subsolid nodules is moderate in subsolid nodules larger than 10 mm. Performance of the visual assessment of CT morphology alone is not sufficient to generally abandon a short-term follow-up for subsolid nodules.

Screen-detected multiple primary lung cancers in the ITALUNG trial

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

Controversies on lung cancers manifesting as part-solid nodules

PURPOSE

Summarise survival of patients with resected lung cancers manifesting as part-solid nodules (PSNs).

METHODS

PubMed/MEDLINE and EMBASE databases were searched for all studies/clinical trials on CT-detected lung cancer in English before 21 December 2015 to identify surgically resected lung cancers manifesting as PSNs. Outcome measures were lung cancer-specific survival (LCS), overall survival (OS), or disease-free survival (DFS). All PSNs were classified by the percentage of solid component to the entire nodule diameter into category PSNs <80% or category PSNs ≥80%.

RESULTS

Twenty studies reported on PSNs <80%: 7 reported DFS and 2 OS of 100%, 6 DFS 96.3-98.7%, and 11 OS 94.7-98.9% (median DFS 100% and OS 97.5%). Twenty-seven studies reported on PSNs ≥80%: 1 DFS and 2 OS of 100%, 19 DFS 48.0%-98.0% (median 82.6%), and 16 reported OS 43.0%-98.0% (median DFS 82.6%, OS 85.5%). Both DFS and OS were always higher for PSNs <80%.

CONCLUSION

A clear definition of the upper limit of solid component of a PSN is needed to avoid misclassification because cell-types and outcomes are different for PSN and solid nodules. The workup should be based on the size of the solid component.

KEY POINTS

• Lung cancers manifesting as PSNs are slow growing with high cure rates. • Upper limits of the solid component are important for correct interpretation. • Consensus definition is important for the management of PSNs. • Median disease-free-survival (DFS) increased with decreasing size of the nodule.

Lung Cancers Associated With Cystic Airspaces: Natural History, Pathologic Correlation, and Mutational Analysis

PURPOSE

The aim of the study was to investigate the natural history of non-small cell lung cancers (NSCLCs) associated with cystic airspaces, including histopathology and molecular analysis.

MATERIALS AND METHODS

A total of 34,801 computed tomographic (CT) scans of 2954 patients diagnosed with NSCLC between 2010 and 2015 were evaluated for association with a cystic airspace. Characteristics on serial CT, 18F-fludeoxyglucose positron emission tomography, and pathologic analysis were recorded.

RESULTS

Cystic airspaces were associated with 1% of NSCLC cases (12 men and 18 women; median age, 66 y [range, 44 to 87 y]). Of the total number of patients, 97% had a smoking history. Twenty-four adenocarcinomas, 4 squamous cell carcinomas, and 2 poorly differentiated carcinomas were distributed throughout all lobes and were predominantly peripheral. Some cystic airspaces appeared in previously normal lungs, whereas others were preceded by subcentimeter nodules. Twenty of 30 cases demonstrated increased soft tissue due to wall thickening, increased loculations, enlargement and/or increased attenuation of a mural nodule, or replacement by a mass. 18F-fludeoxyglucose uptake was present if solid components measured >8 mm. Twenty of 30 patients demonstrated >1 cystic lesion or ground-glass nodule, lymphadenopathy, or evidence of prior lung resection. Pathologic analysis revealed that cystic airspaces correspond to a check-valve mechanism, adenocarcinoma superimposed on emphysema, cystification, and adenocarcinoma parasitizing a preexisting bulla. Fourteen of 26 tumors and 64% of adenocarcinomas tested positive for an alteration of KRAS with or without other alterations.

CONCLUSIONS

Cystic airspaces preceded by nodules can evolve into NSCLCs. Wall thickening and/or mural nodularity may develop. Location in the periphery of the upper lobes, emphysema, additional cystic lesions or ground-glass nodules, lymphadenopathy, and prior lung cancer should further increase suspicion. Cystic airspaces on CT can be due to a check-valve mechanism obstructing the small airways, lepidic growth of adenocarcinoma in an area of emphysema, cystification of tumor due to degeneration, or adenocarcinoma growing along the wall of a preexisting bulla. KRAS mutations are the predominant genetic alterations.

Computer-Aided Diagnosis of Ground-Glass Opacity Nodules Using Open-Source Software for Quantifying Tumor Heterogeneity

OBJECTIVE

The purposes of this study are to develop quantitative imaging biomarkers obtained from high-resolution CTs for classifying ground-glass nodules (GGNs) into atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IAC); to evaluate the utility of contrast enhancement for differential diagnosis; and to develop and validate a support vector machine (SVM) to predict the GGN type.

MATERIALS AND METHODS

The heterogeneity of 248 GGNs was quantified using custom software. Statistical analysis with a univariate Kruskal-Wallis test was performed to evaluate metrics for significant differences among the four GGN groups. The heterogeneity metrics were used to train a SVM to learn and predict the lesion type.

RESULTS

Fifty of 57 and 51 of 57 heterogeneity metrics showed statistically significant differences among the four GGN groups on unenhanced and contrast-enhanced CT scans, respectively. The SVM predicted lesion type with greater accuracy than did three expert radiologists. The accuracy of classifying the GGNs into the four groups on the basis of the SVM algorithm was 70.9%, whereas the accuracy of the radiologists was 39.6%. The accuracy of SVM in classifying the AIS and MIA nodules was 73.1%, and the accuracy of the radiologists was 35.7%. For indolent versus invasive lesions, the accuracy of the SVM was 88.1%, and the accuracy of the radiologists was 60.8%. We found that contrast enhancement does not significantly improve the differential diagnosis of GGNs.

CONCLUSION

Compared with the GGN classification done by the three radiologists, the SVM trained regarding all the heterogeneity metrics showed significantly higher accuracy in classifying the lesions into the four groups, differentiating between AIS and MIA and between indolent and invasive lesions. Contrast enhancement did not improve the differential diagnosis of GGNs.

Radiological classification of multiple lung cancers and the prognostic impact based on the presence of a ground glass opacity component on thin-section computed tomography

OBJECTIVES

Revised TNM classification has proposed a new clinical classification of lung cancers with multiple pulmonary sites. However, definition of the radiological findings and their prognostic impacts are still controversial. Therefore, we evaluated the prognostic impact of multiple lung cancers based on the radiologic classifications concluded from findings on thin-section computed tomography.

METHODS

Among surgically resected 1440 c-stage I lung cancer patients, 246 (17.1%) with multiple lung tumors were reviewed. All tumors were classified into 3 groups based on the extent of ground glass opacity (GGO), i.e., consolidation tumor ratio (CTR); GGO-dominant (GD; 0≤CTR<0.5), solid-dominant (SD; 0.5≤CTR<1.0) and pure-solid (PS; CTR=1.0). Multiple lung tumors were divided radiologically into 6 groups, and their prognoses were compared with that of c-stage I lung cancer using Cox's proportional hazard model.

RESULTS

Of all, 198 patients (80.5%) were surgically resected more than two tumors and determined as multiple lung cancers pathologically. The number of patients with GD+GD=73 (30%), GD+SD=54 (22%), GD+PS=53 (21%), SD+SD=12 (5%), SD+PS=20 (8%) and PS+PS=34 (14%). A multivariate analysis revealed that PS+PS group consisted of independently significant prognosticator (p<0.001). The overall survival (OS) was 97.3% in GD+GD, 98.2% in GD+SD, 84.8% in GD+PS, 90.9% in SD+SD, 78.7% in SD+PS and 41.8% in PS+PS groups, showing a significant difference between PS+PS group and the other groups. Furthermore, the OS of 1194 c-stage I lung cancer patients was 78.2%, and the prognosis of PS+PS group was significantly poor compared with that of c-stage I (p<0.001), while OS of the other groups were almost equivalent or much better than the c-stage I.

CONCLUSIONS

Among multiple lung cancers, PS+PS group is associated with poor survival, which would contribute to the upstaging of T descriptors. The presence of GGO is extremely important when considering the correlation between radiological classification of multiple lung cancers and its prognosis.

Evaluation of grading systems in stage I lung adenocarcinomas: a retrospective cohort study

AIMS

There is no internationally accepted grading system for lung adenocarcinoma despite the new WHO classification. The architectural grade, the Kadota grade and the Sica score were evaluated and compared with overall (OS) and disease-free survival (DFS).

METHODS

Comprehensive histological subtyping was used in a series of resected stage I lung adenocarcinoma to identify subtypes of adenocarcinomas, the architectural grade, the Kadota grade, the Sica grade, the mitotic count, nuclear atypia, the presence of lymphovascular, vascular and airway propagation, necrosis, and micropapillary or solid growth pattern in any percentage. Statistical models fitted included Kaplan-Meier estimates and Cox proportional hazard regression models.

RESULTS

261 stage I adenocarcinomas were included. The 5-year survivals of different subtypes were as follows: lepidic (n=40, OS: 92.5%; DFS 91.6%), acinar (n=54, OS: 81.8%; DFS: 68.6%), papillary (n=49, OS: 73.6%; DFS: 61.0%), solid (n=95, OS: 64.7%; DFS: 57.8%) and micropapillary (n=23, OS: 34.8%; DFS: 33.5%). Concerning the architectural grade, there were significant differences between OS and DFS of low and intermediate (pOS=0.005, pDFS<0.001), low and high (pOS<0.001, pDFS<0.001) and intermediate and high grades (pOS=0.002, pDFS<0.001). Low-grade and intermediate grade tumours did not differ in survival according to Kadota grade and Sica grade. In the multivariable model, architectural grade was found to be an independent prognostic marker. In another model, architectural pattern proved to be superior to architectural grade.

CONCLUSIONS

Of the three grading systems compared, the architectural grade makes the best distinction between the outcome of low-grade, intermediate-grade and high-grade stage I adenocarcinomas.

An Immunohistochemical Study of Anaplastic Lymphoma Kinase and Epidermal Growth Factor Receptor Mutation in Non-Small Cell Lung Carcinoma

INTRODUCTION

Lung cancer is one of the leading causes of cancer related death. Targeted treatment for specific markers may help in reducing the cancer related morbidity and mortality.

AIM

To study expression of Anaplastic Lymphoma Kinase (ALK)and Epidermal Growth Factor Receptor (EGFR) mutations in patients of Non-Small Cell Lung Cancer NSCLC, that are the targets for specific ALK inhibitors and EGFR tyrosine kinase inhibitors.

MATERIALS AND METHODS

Total 69 cases of histologically diagnosed NSCLC were examined retrospectively for immunohistochemical expression of EGFR and ALK, along with positive control of normal placental tissue and anaplastic large cell lymphoma respectively.

RESULTS

Of the NSCLC, Squamous Cell Carcinoma (SCC) accounted for 71.0% and adenocarcinoma was 26.1%. ALK expression was seen in single case of 60-year-old female, non-smoker with adenocarcinoma histology. EGFR expression was seen in both SCC (59.18%) and adenocarcinoma in (77.78%) accounting for 63.77% of all cases. Both ALK and EGFR mutation were mutually exclusive.

CONCLUSION

EGFR expression was seen in 63.77% of cases, highlighting the importance of its use in routine analysis, for targeted therapy and better treatment results. Although, ALK expression was seen in 1.45% of all cases, it is an important biomarker in targeted cancer therapy. Also, the mutually exclusive expression of these two markers need further studies to develop a diagnostic algorithm for NSCLC patients.

Use of Oncogenic Driver Mutations in Staging of Multiple Primary Lung Carcinomas: A Single-Center Experience

OBJECTIVE

The staging of multiple pulmonary adenocarcinomas requires the distinction of intrapulmonary metastasis (IPM) from multiple primary lung cancers (MPLCs). This can be challenging in some patients, and the addition of data from oncogenic driver mutations in these tumors may be helpful in this determination.

METHODS

As a proof of principle, molecular driver results from primary tumors and their metastases in 45 patients were compared (cohort 1). Then, 69 patients with a total of 154 synchronous or metachronous lung carcinomas were identified, and the pathologic findings were compared with oncogenic driver mutation. Each patient was assigned a highest potential T or M category on the basis of clinical, histopathologic, and molecular findings (cohort 2).

RESULTS

The concordance rate of EGFR, KRAS, BRAF, and ALK receptor tyrosine kinase gene (ALK) mutations was 96% in cohort 1. In cohort 2, 36% of multiple same-lobe nodules were MPLCs, 40% were IPM, and 24% were noninformative by molecular findings. Of nodules with multiple lobe involvement, 81.5% were MPLCs and 7.4% were IPM, with 11% noninformative. Of metachronous tumors, 52.9% were MPLCs. Overall survival was 100% at 2 years, 95% at 3 years, and 80% at 4 years in patients with available follow-up.

CONCLUSIONS

Oncogenic driver mutations are concordant between primary tumors and metastasis. The largest proportion of MPLCs was seen in tumors of multiple lobes, but with a substantial proportion of MPLCs among single-lobe nodules and with metachronous tumors. Overall survival was higher than expected for the respective highest T or M category, which is in support of the high frequency of MPLC.

The relationship of cancer characteristics and patient outcome with time to lung cancer diagnosis after an abnormal screening CT

PURPOSE

The National Lung Screening Trial (NLST) demonstrated a reduction in lung cancer and all-cause mortality with low-dose CT (LDCT) screening. The aim of our study was to examine the time to diagnosis (TTD) of lung cancer in the LDCT arm of the NLST and assess its relationship with cancer characteristics and survival.

METHODS

The subjects (N = 462) with a positive baseline screen and subsequent lung cancer diagnosis within 3 years were evaluated by data and image review to confirm the baseline abnormality. The cases were analysed for the relationship between TTD and imaging features, cancer type, stage and survival for 7 years from baseline screen.

RESULTS

Cancer was judged to be present at baseline in 397/462 cases. The factors that showed significant association (p value trend less than 0.05) with longer TTD included smaller nodule size, pure ground glass nodules (GGNs), smooth/lobulated margins, stages I/II, adenocarcinoma, and decreasing lung cancer mortality. The logistic regression model for lung cancer death showed significant inverse relationships with size less than 20 mm (OR = 0.32), pure GGNs (OR = 0.24), adenocarcinoma (OR = 0.57) and direct relationship with age (OR = 1.4).

CONCLUSION

TTD after a positive LDCT screen in the NLST showed a strong association with imaging features, stage and mortality.

KEY POINTS

• NLST observed variable time to lung cancer diagnosis from positive baseline screen. • Time to diagnosis was associated with imaging features, cancer type and stage. • In univariate but not multivariate analysis, longer TTD correlated with decreased mortality.

Computed Tomography Screening for Lung Cancer: Mediastinal Lymph Node Resection in Stage IA Nonsmall Cell Lung Cancer Manifesting as Subsolid and Solid Nodules

OBJECTIVE

To compare long-term survival rates of patients with first, primary, clinical stage IA nonsmall cell lung cancer from a large cohort undergoing computed tomography screening with and without mediastinal lymph node resection (MLNR) under an Institutional Review Board-approved common protocol from 1992 to 2014.

BACKGROUND

Assessing survival differences of patients with and without MLNR manifesting as solid and subsolid nodules.

METHODS

Long-term Kaplan-Meier (K-M) survival rates for those with and without MLNR were compared and Cox regression analyses were used to adjust for demographic, computed tomography, and surgical covariates.

RESULTS

The long-term K-M rates for 462 with and 145 without MLNR was 92% versus 96% (P = 0.19), respectively. For 203 patients with a subsolid nodule, 151 with and 52 without MLNR, the rate was 100%. For the 404 patients with a solid nodule, 311 with and 93 without MLNR, the rate was 87% versus 94% (P = 0.24) and Cox regression showed no statistically significant difference (P = 0.28) when adjusted for all covariates. Risk of dying increased significantly with increasing decades of age (hazard ratio [HR] 2.3, 95% confidence interval [CI] 1.4-3.8), centrally located tumor (HR 2.5, 95% CI 1.2-5.2), tumor size 21 to 30 mm (HR 2.7, 95% CI 1.2-6.0), and invasion beyond the lung stroma (HR 3.0, 95% CI 1.4-6.1). For the 346 patients with MLNR, tumor size was 20 mm or less; K-M rates for the 269 patients with and 169 patients without MLNR were also not significantly different (HR 2.1, P = 0.24).

CONCLUSIONS

It is not mandatory to perform MLNR when screen-diagnosed nonsmall cell lung cancer manifests as a subsolid nodule.

Current Controversies in Lung Cancer Staging

Lung cancer remains the leading cause of cancer-related mortality in the United States, and accurate staging of disease plays an important role in the formulation of treatment strategies and optimization of patient outcomes. The International Association for the Study of Lung Cancer has recently proposed changes to the upcoming eighth edition of the tumor, node, and metastasis (TNM-8) staging system used for lung cancer. This revised classification is based on significant differences in patient survival identified on analysis of a new large international database of lung cancer cases. Key changes include: further modifications to the T descriptors based on 1 cm increments in tumor size; grouping of tumors resulting in partial or complete lung atelectasis/pneumonitis; grouping of tumors involving a main bronchus with respect to distance from the carina; reassignment of diaphragmatic invasion; elimination of mediastinal pleural invasion as a descriptor; and further subdivision of metastatic disease into distinct descriptors based on the number of extrathoracic metastases and involved organs. Because of these changes, several new stage groups have been developed, and others have shifted. Although TNM-8 represents continued improvement upon modifications previously made to the staging system, reflecting an evolving understanding of tumor behavior and patient management, several limitations and unaddressed issues persist. Understanding the proposed revisions to TNM-8 and awareness of key limitations and potential controversial issues still unaddressed will allow radiologists to accurately stage patients with lung cancer and optimize treatment decisions.

Study of lung cancer regulatory network that involves erbB4 and tumor marker gene

Our purpose is to screen out serum tumor markers closely correlated to the nature of solitary pulmonary nodule (SPN) and to draw a regulatory network containing genes correlated to lung cancer. Two hundred and sixty cases of SPN patients confirmed through pathological diagnosis were collected as subjects, factors closely correlated to the nature of SPN were screened out from eight tumor markers through Fisher discriminant method, and functional annotation and pathway analysis were conducted on erbB4 as well as its tumor marker genes by GO and KEGG databases. Four key tumor markers: CYFRA21-1, CA125, SCC-Ag and CA153 were successfully screened out and the first three proteins’ corresponding gene were KRT19, MUC16 and SERPINB3 while that of CA153 was not found. GO analysis on erbB4, KRT19, MUC16 and SERPINB3 showed that they covered three domains, cell components, molecular function and biological process; meanwhile, combined with KEGG database and based on signal pathway of erbB4, a regulatory network of lung cancer cells escaping from apoptosis was successfully made. This study indicates that serum tumor marker genes play an important role in the occurrence and development of lung cancer, besides, this study primarily discussed the molecular mechanism of these tumor markers in predicting tumor, which provides a basis for in-depth information about lung cancer.

Lung Cancers Manifesting as Part-Solid Nodules in the National Lung Screening Trial

OBJECTIVE

The objective of our study was to determine how often death occurred from lung cancers that manifested as part-solid nodules in the National Lung Screening Trial (NLST).

MATERIALS AND METHODS

NLST radiologists classified nodules as solid, ground-glass, or mixed. All lung cancers classified as mixed nodules by NLST radiologists were reviewed by four experienced radiologists and reclassified as solid, nonsolid, or part-solid nodules. When possible, volume doubling times (VDTs) were calculated separately for the entire nodule and for the solid component of the nodule.

RESULTS

Of 88 screening-diagnosed lung cancer cases identified by the NLST radiologists as mixed nodules, study radiologists confirmed that 19 were part-solid nodules. All the part-solid nodules were present at baseline (time 0), and none of the patients with a part-solid nodule had lymph node enlargement at CT before diagnosis or metastases at resection. Multilobar stage IV (T4N0M1) bronchioloalveolar carcinoma was diagnosed in one patient 25.0 months after study randomization, and the patient died 67.9 months after randomization. All 18 patients with a solitary or dominant part-solid nodule underwent surgery, and none died of lung cancer. From randomization, the average time to diagnosis was 18.6 months and the average time of follow-up was 79.2 months. On the last CT examination performed before diagnosis, the average size of the solid component of the part-solid nodules was 9.2 mm (SD, 4.9); the solid component was larger than 10 mm in five patients. The median VDT based on the entire nodule was 476 days, and the median VDT based on the solid component alone was 240 days.

CONCLUSION

None of the patients with lung cancer manifesting as a solitary or dominant part-solid nodule had lymph node enlargement or metastases at pathology, and none died of lung cancer within the follow-up time of the NLST.

Clinical implications of genetic heterogeneity in multifocal pulmonary adenocarcinomas

Multifocal pulmonary adenocarcinomas are increasingly encountered in clinical practice, in part due to the increased availability and improvement in the thoracic imaging. Recognized as a distinct entity in the upcoming 8^th edition of American Joint Commission on Cancer (AJCC) staging system, multifocal adenocarcinomas exhibit several unique features such as the characteristic appearance of multiple ground glass opacities or nodules in computerized tomography (CT). Recent studies have suggested that the vast majority of these malignant lesions are genetically independent even when occurring synchronously in a single patient. For instance, the pattern of epidermal growth factor receptor (EGFR) mutations in multifocal pulmonary adenocarcinomas can vary from one lesion to another. This observation has several important clinical implications. These include the potential need to perform multiple molecular tests on multiple lesions, the possible role of molecular marker such as EGFR mutation in the staging of questionable multiple lung cancers, and the justification for empirical use EGFR inhibitors for multifocal adenocarcinomas among high-prevalence population when no known mutation has been detected.

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

Objectives

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

Materials and Methods

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

Results

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

Conclusion

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

Comprehensive study of mutational and clinicopathologic characteristics of adenocarcinoma with lepidic pattern in surgical resected lung adenocarcinoma

PURPOSE

Although many studies have explored clinicopathologic characteristics and prognosis of lung adenocarcinoma, a few literatures reported the mutational status of lung adenocarcinomas with lepidic pattern and whether there is difference between adenocarcinomas with pure lepidic component and lepidic predominant adenocarcinomas remain unknown.

METHODS

One hundred and thirty-three patients including 92 adenocarcinomas with pure lepidic component and 41 lepidic predominant adenocarcinomas were subjected to the study. All the clinicopathologic data, the follow-up information and the status of gene mutations including EGFR, KRAS, HER2, BRAF, AKT1, ALK, RET and ROS1 were investigated.

RESULTS

Of the 133 lung adenocarcinomas with lepidic pattern, 87.22 % (116/133) were detected harboring mutations in our tested genes, among which 90.52 % (105/116) harbored EGFR mutation. There are three KRAS mutations and two BRAF mutations in our cohort, and we revealed two ALK fusion and one RET fusion. No ROS1 fusion was discovered. There was no significant difference in gene mutations between adenocarcinomas with pure lepidic component and lepidic predominant adenocarcinomas except EGFR mutation (p = 0.039). Lepidic predominant adenocarcinomas seemed to have more EGFR mutation. The post-recurrence survival was significantly prolonged in patients who received TKIs.

CONCLUSIONS

Adenocarcinoma with lepidic pattern is a low-grade lung tumor with favorable prognosis and displays frequent EGFR mutation. Compared with lepidic predominant adenocarcinomas, lung adenocarcinomas with pure lepidic component have a better prognosis. On the basis of these results, we also suggested the application of EGFR-TKIs therapy for EGFR mutation-positive patients after recurrence could achieve prolonged survival.

CT Screening for Lung Cancer: Part-Solid Nodules in Baseline and Annual Repeat Rounds

OBJECTIVE

The purpose of this study was to assess the frequencies of identifying participants with part-solid nodules, of diagnostic pursuit, of diagnoses of lung cancer, and long-term lung cancer survival in baseline and annual repeat rounds of CT screening in the International Early Lung Cancer Action Project.

MATERIALS AND METHODS

Screenings were performed under a common protocol. Participants with solid, nonsolid, and part-solid nodules and the diagnoses of lung cancer were documented.

RESULTS

Part-solid nodules were identified in 2892 of 57,496 (5.0%) baseline screening studies; 567 (19.6%) of these nodules resolved or decreased in size. Diagnostic pursuit led to the diagnosis of adenocarcinoma in 79 cases, all clinical stage I. At resection, one nodule (12-mm solid component) had a single N2 metastasis. A new part-solid nodule was identified in 541 of 64,677 (0.8%) annual repeat screenings; 377 (69.7%) of these nodules resolved or decreased in size. In eight cases among the 541, the diagnosis of adenocarcinoma manifesting as a part solid nodule was made; on retrospective review the nodule originally had been a nonsolid nodule. In another 20 cases, the cancer originally had manifested as a nonsolid nodule but had progressed to become part-solid at annual repeat screening before any diagnosis was pursued. These 28 annual repeat cases of lung cancer were all pathologic stage IA. Of the 107 cases of lung cancer (79 baseline cases and 28 annual repeat cases), 106 were surgically resected, and one baseline case was followed up with imaging for 4 years. The lung cancer survival rate was 100% with a median follow-up period from diagnosis of 89 months (interquartile range, 52-134 months).

CONCLUSION

Lung cancers manifesting as part-solid nodules at repeat screening studies all started as nonsolid nodules. Among 107 cases of adenocarcinoma manifesting as a part-solid nodule, a single lymph node metastasis was found in a single case (solid component, 12 mm).

Microenvironmental changes in the progression from adenocarcinoma in situ to minimally invasive adenocarcinoma and invasive lepidic predominant adenocarcinoma of the lung

OBJECTIVES

Invasive lepidic predominant adenocarcinoma (LPA) of the lung is thought to progress in a stepwise fashion from adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA). The aim of this study was to investigate the microenvironmental changes during the development from AIS to LPA.

MATERIALS AND METHODS

Clinicopathological characteristics of AIS (n=51), MIA (n=59), LPA smaller than 3cm (LPA-S, n=113), and LPA larger than 3cm (LPA-L, n=47) were analyzed. We then evaluated the expression levels of epithelial-mesenchymal transition (EMT)-related molecules (E-cadherin, S100A4), invasion-related molecules (laminin-5, ezrin), stem-cell-related molecules (ALDH-1), and growth factor receptors (c-Met, EGFR) in cancer cells of each group (n=20). The number of tumor-promoting stromal cells, including podoplanin-positive cancer-associated fibroblasts (PDPN+ CAFs), CD204-positive tumor-associated macrophages (CD204+ TAMs), and CD34+ microvessel cells, were also analyzed.

RESULTS

No significant difference in these characteristics was found between LPA-S and LPA-L. Laminin-5 expression in the non-invasive carcinoma component of MIA was significantly higher than that of AIS (p<0.001). During the progression from MIA to LPA-S, the expression level of laminin-5 in the invasive carcinoma component was significantly elevated (p<0.01). Moreover, tumor-promoting stromal cells were more frequently recruited in the invasive area of LPA-S (PDPN+ CAFs; p<0.05, CD204+ TAMs; p<0.001, CD34+ microvessel; p<0.05). Ezrin expression in the invasive carcinoma component of LPA-L was significantly increased (p<0.05) compared to LPA-S; however, the number of tumor-promoting stromal cells were not different between these two groups.

CONCLUSION

Our current results indicated that microenvironmental molecular changes occur during the progression from MIA to LPA-S and suggested that this process may play an important role in disease progression from AIS to LPA.

[Diffuse and calcified nodular opacities]

Pulmonary adenocarcinoma is difficult to identify right away with respect to anamnestic and even to radiological data. We here report the case of a woman with dyspnea. Radiological examination showed disseminated micronodular opacity confluent in both lung fields with calcifications in certain locations. Histological examination of transbronchial biopsies allowed the diagnosis. The prognosis was poor with the death of the patient.

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.

[Clinical Study of Surgical Treatment of Non-small Cell Lung Cancer 10 mm or Less in Diameter Under Video-assisted Thoracoscopy]

背景与目的

早期原发性非小细胞肺癌（non-small cell lung cancer, NSCLC）的手术切除及淋巴结切除的合理方式存在较大争议，本研究旨在探讨直径≤10 mm的原发NSCLC的微创切除及淋巴结切除的手术方式。

方法

对2013年7月-2016年3月在我院接受电视胸腔镜手术（video-assisted thoracic surgery, VATS）治疗并有明确病理诊断为NSCLC的共46例患者的临床资料进行回顾性分析。所有患者术前行薄层计算机断层扫描（computed tomography, CT），实性结节5例，混合性磨玻璃结节（mixed ground-glass opacity, mGGO）23例，纯磨玻璃结节（pure ground-glass opacity, pGGO）18例。根据患者具体情况采用不同术式，包括VATS肺叶切除和系统性淋巴结清扫，VATS肺楔形切除和选择性淋巴结切除，VATS肺段切除和选择性淋巴结切除，或仅采用VATS肺楔形切除。其中7例术前行CT引导下Hook-wire定位。

结果

VATS肺叶切除和系统性淋巴结清扫23例（mGGOs 15例，pGGOs 4例，实性结节4例），只有1例实性腺癌结节出现N2淋巴结转移，VATS肺楔形切除和选择性淋巴结切除5例（mGGOs 2例，pGGOs 3例）和VATS肺段切除和选择性淋巴结切除4例（mGGOs 2例，pGGOs 2例）均无淋巴结转移，仅采用VATS肺楔形切除14例（mGGOs 4例，pGGOs 9例，实性结节1例）。7例Hook-wire定位均成功。围手术期无重大并发症，随访1个月-26个月，平均（13.7±8.7）个月，无复发及转移。

结论

直径≤10 mm以mGGO和pGGO为表现的原发性NSCLC淋巴结转移率低，术中可以不进行淋巴结的清扫，实性结节应选择性淋巴结切除或系统性淋巴结清扫。高龄和心肺功能差的患者可以选择楔形切除或肺段切除。术前运用Hook-wire定位安全有效，可为VATS提供便利。

The importance of the regimen of screening in maximizing the benefit and minimizing the harms

BACKGROUND

In CT screening for lung cancer, the regimen of screening is critical in diagnosing lung cancer early while limiting unnecessary tests and invasive procedures. The International Early Lung Cancer Action Program (I-ELCAP) has developed a regimen based on evidence collected in the I-ELCAP cohort of more than 70,000 participants.

METHODS

Important in the development of the regimen is the recognition of the profound difference between the first, baseline round of screening and all subsequent rounds of repeat screening. For each person undergoing screening, the baseline round happens only once while repeat rounds will be performed annually for many years. This difference needs to be clearly recognized as it is these annual rounds which allow for identification of small, early, yet aggressive, lung cancers which have high cure rates despite their aggressiveness. The importance of nodule consistency and size are key factors in the regimen. The regimen needs to be continuously updated by incorporating advances in technology and knowledge.

RESULTS

The use of the I-ELCAP regimen reduces the workup of participants in the screening program to less than 10% in the baseline round and less than 6% in the annual repeat rounds. By use of this regimen, estimated cure rate of lung cancers diagnosed under screening is 80% or higher in both baseline and annual repeat rounds.

CONCLUSIONS

The I-ELCAP collaboration provides a new paradigm that answers the 2002 NCI call for multiple approaches to address relevant questions about screening and the Institute of Medicine (IOM) Roundtable on Evidence-based Medicine from the National Academy of Science's call for a "new clinical research paradigm that takes better advantage of data generated in the course of healthcare delivery would speed and improve the development of evidence for real-world decision making".

The IASLC Lung Cancer Staging Project: Background Data and Proposals for the Application of TNM Staging Rules to Lung Cancer Presenting as Multiple Nodules with Ground Glass or Lepidic Features or a Pneumonic Type of Involvement in the Forthcoming Eighth Edition of the TNM Classification

INTRODUCTION

Application of tumor, node, and metastasis (TNM) classification is difficult in patients with lung cancer presenting as multiple ground glass nodules or with diffuse pneumonic-type involvement. Clarification of how to do this is needed for the forthcoming eighth edition of TNM classification.

METHODS

A subcommittee of the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee conducted a systematic literature review to build an evidence base regarding such tumors. An iterative process that included an extended workgroup was used to develop proposals for TNM classification.

RESULTS

Patients with multiple tumors with a prominent ground glass component on imaging or lepidic component on microscopy are being seen with increasing frequency. These tumors are associated with good survival after resection and a decreased propensity for nodal and extrathoracic metastases. Diffuse pneumonic-type involvement in the lung is associated with a worse prognosis, but also with a decreased propensity for nodal and distant metastases.

CONCLUSION

For multifocal ground glass/lepidic tumors, we propose that the T category be determined by the highest T lesion, with either the number of tumors or m in parentheses to denote the multifocal nature, and that a single N and M category be used for all the lesions collectively-for example, T1a(3)N0M0 or T1b(m)N0M0. For diffuse pneumonic-type lung cancer we propose that the T category be designated by size (or T3) if in one lobe, as T4 if involving an ipsilateral different lobe, or as M1a if contralateral and that a single N and M category be used for all pulmonary areas of involvement.

Comparison of outcomes for patients with lepidic pulmonary adenocarcinoma defined by 2 staging systems: A North American experience

OBJECTIVE

Application of the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) classification of lepidic adenocarcinomas in conjunction with American Joint Committee on Cancer (AJCC) staging has been challenging. We aimed to compare IASLC/ATS/ERS and AJCC classifications, to determine if they could be integrated as a single staging system.

METHODS

We reviewed patients from 2001-2013 who had AJCC stage I lepidic adenocarcinomas, and categorized them according to IASLC/ATS/ERS guidelines: adenocarcinoma in situ (AIS); minimally invasive adenocarcinoma (MIA); or invasive adenocarcinoma (IA). We integrated the 2 classification systems by separating AIS and MIA as being stage 0, and routinely classifying IA as stage I.

RESULTS

Median follow-up was 52 months in 138 patients. The IASLC/ATS/ERS classification demonstrated a higher disease-free survival (DFS) in AIS (100%) and MIA (96%) versus IA (80%) (P = .022), and higher overall survival (OS): 100% for AIS and MIA, versus 90% for IA (P = .049). The AJCC classification identified a DFS of 87% and an OS of 94% for stage I patients. Integration of the 2 systems demonstrated higher DFS in stage 0 (98%) versus I (80%) (P = .006), and higher OS: 100% for stage 0 versus 90% for stage I (P = .014).

CONCLUSIONS

The IASLC/ATS/ERS classification better discriminates AIS and MIA compared with current AJCC staging; however, integration suggests that these categories may be collectively classified in AJCC staging, based on similarly favorable outcomes and distinctive survival rates.

Prognosis and status of lymph node involvement in patients with adenocarcinoma in situ and minimally invasive adenocarcinoma-a systematic literature review and pooled-data analysis

BACKGROUND

Adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) have been brought up that substitute for bronchioloalveolar carcinoma (BAC), according to the new classification of lung adenocarcinoma. There has been increasing opinions that argues for the adjustment of lymph node disposition in patients with such early stage tumors. Therefore, we sought to overview the prognosis and status of lymph node involvement in AIS/MIA patients.

METHODS

PubMed, Springer and Ovid databases were searched for relevant studies. Data was extracted and results summarized to demonstrate the disposition of lymph nodes in AIS/MIA.

RESULTS

Twenty-three studies consisting of 6,137 lung adenocarcinoma were included. AIS/MIA accounted for 821 of the total 6,137. All included patients received curative surgery. After a review of the summarized data we found that only one patient (with MIA) had N1 node metastasis, N2 disease was not found in any of the included patients. In concordance with this, studies that reported 5-year disease free survival (5-year DFS) have almost 100% rate.

CONCLUSIONS

Our findings indicated that patients with AIS/MIA have good survival prognosis after surgical resection, and that recurrence and lymph node metastasis in these patients is rare. Therefore, we strongly encouraged further studies to determine the role of different lymph node disposition strategies.

Radiologic Evaluation of Small Lepidic Adenocarcinomas to Guide Decision Making in Surgical Resection

BACKGROUND

The International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification of pulmonary adenocarcinomas identifies indolent lesions associated with low recurrence, superior survival, and the potential for sublobar resection. The distinction, however, is determined on the pathologic evaluation, limiting preoperative surgical planning. We sought to determine whether preoperative computed tomography (CT) characteristics could guide decisions about the extent of the pulmonary resection.

METHODS

We reviewed the preoperative CT scans for 136 patients identified to have adenocarcinomas with lepidic features on the final pathologic evaluation. The solid component on CT was substituted for the invasive component, and patients were radiologically classified as adenocarcinoma in situ, 3 cm or less with no solid component; minimally invasive adenocarcinoma, 3 cm or less with a solid component of 5 mm or less; or invasive adenocarcinoma, exceeding 3 cm or solid component exceeding 5 mm, or both. Analysis of variance, t test, χ(2) test, and Kaplan-Meier methods were used for analysis.

RESULTS

The radiologic classification identified 35 adenocarcinomas in situ (26%) and 12 minimally invasive (9%) and 89 invasive adenocarcinoma (65%) lesions. At a 32-month median follow-up, patient outcomes associated with the radiologic classification were similar to the pathologic-based classification: the radiologic classification identified 14 of 16 patients with recurrent disease and all 6 who died of lung cancer. In addition, patients with radiologic adenocarcinoma in situ and minimally invasive adenocarcinoma who underwent sublobar resections had no recurrence and 100% disease-free and overall survival at 5 years.

CONCLUSIONS

The radiologic classification of patients with lepidic adenocarcinomas is associated with similar oncologic and survival outcomes compared with the pathologic classification and may guide decision making in the approach to surgical resection.

Management of subsolid pulmonary nodules in CT lung cancer screening

The distinct appearance and behavior of subsolid pulmonary nodules (SSNs) has resulted in separate recommendations for the management of solitary SSNs, both for incidentally detected as well as for screen detected nodules. However, these guidelines have been based primarily on expert opinion. Recently two studies were published regarding SSNs detected in low-dose computed tomography (LDCT) lung cancer screening, including management advices.

CT Screening for Lung Cancer: Nonsolid Nodules in Baseline and Annual Repeat Rounds

PURPOSE

To address the frequency of identifying nonsolid nodules, diagnosing lung cancer manifesting as such nodules, and the long-term outcome after treatment in a prospective cohort, the International Early Lung Cancer Action Program.

MATERIALS AND METHODS

A total of 57,496 participants underwent baseline and subsequent annual repeat computed tomographic (CT) screenings according to an institutional review board, HIPAA-compliant protocol. Informed consent was obtained. The frequency of participants with nonsolid nodules, the course of the nodule at follow-up, and the resulting diagnoses of lung cancer, treatment, and outcome are given separately for baseline and annual repeat rounds of screening. The χ(2) statistic was used to compare percentages.

RESULTS

A nonsolid nodule was identified in 2392 (4.2%) of 57,496 baseline screenings, and pathologic pursuit led to the diagnosis of 73 cases of adenocarcinoma. A new nonsolid nodule was identified in 485 (0.7%) of 64,677 annual repeat screenings, and 11 had a diagnosis of stage I adenocarcinoma; none were in nodules 15 mm or larger in diameter. Nonsolid nodules resolved or decreased more frequently in annual repeat than in baseline rounds (322 [66%] of 485 vs 628 [26%] of 2392, P < .0001). Treatment of the cases of lung cancer was with lobectomy in 55, bilobectomy in two, sublobar resection in 26, and radiation therapy in one. Median time to treatment was 19 months (interquartile range [IQR], 6-41 months). A solid component had developed in 22 cases prior to treatment (median transition time from nonsolid to part-solid, 25 months). The lung cancer-survival rate was 100% with median follow-up since diagnosis of 78 months (IQR, 45-122 months).

CONCLUSION

Nonsolid nodules of any size can be safely followed with CT at 12-month intervals to assess transition to part-solid. Surgery was 100% curative in all cases, regardless of the time to treatment.

Observer Variability for Classification of Pulmonary Nodules on Low-Dose CT Images and Its Effect on Nodule Management

PURPOSE

To examine the factors that affect inter- and intraobserver agreement for pulmonary nodule type classification on low-radiation-dose computed tomographic (CT) images, and their potential effect on patient management.

MATERIALS AND METHODS

Nodules (n = 160) were randomly selected from the Dutch-Belgian Lung Cancer Screening Trial cohort, with equal numbers of nodule types and similar sizes. Nodules were scored by eight radiologists by using morphologic categories proposed by the Fleischner Society guidelines for management of pulmonary nodules as solid, part solid with a solid component smaller than 5 mm, part solid with a solid component 5 mm or larger, or pure ground glass. Inter- and intraobserver agreement was analyzed by using Cohen κ statistics. Multivariate analysis of variance was performed to assess the effect of nodule characteristics and image quality on observer disagreement. Effect on nodule management was estimated by differentiating CT follow-up for ground-glass nodules, solid nodules 8 mm or smaller, and part-solid nodules smaller than 5 mm from immediate diagnostic work-up for solid nodules larger than 8 mm and part-solid nodules 5 mm or greater.

RESULTS

Pair-wise inter- and intraobserver agreement was moderate (mean κ, 0.51 [95% confidence interval, 0.30, 0.68] and 0.57 [95% confidence interval, 0.47, 0.71]). Categorization as part-solid nodules and location in the upper lobe significantly reduced observer agreement (P = .012 and P < .001, respectively). By considering all possible reading pairs (28 possible combinations of observer pairs × 160 nodules = 4480 possible agreements or disagreements), a discordant nodule classification was found in 36.4% (1630 of 4480), related to presence or size of a solid component in 88.7% (1446 of 1630). Two-thirds of these discrepant readings (1061 of 1630) would have potentially resulted in different nodule management.

CONCLUSION

There is moderate inter- and intraobserver agreement for nodule classification by using current recommendations for low-radiation-dose CT examinations of the chest. Discrepancies in nodule categorization were mainly caused by disagreement on the size and presence of a solid component, which may lead to different management in the majority of cases with such discrepancies. (©) RSNA, 2015.

What are the radiologic findings predictive of indolent lung adenocarcinoma?

OBJECTIVE

Small pulmonary nodules are often followed up. This study aimed to establish radiographic criteria with which to accurately and reproducibly predict indolent cancers including adenocarcinoma in situ.

METHODS

We examined correlations between pre-operative factors and surgical outcomes, including pathological findings and prognosis among 609 patients with clinical Stage IA lung adenocarcinoma that had been completely resected at multiple institutions. Indolent cancers were defined as tumors without lymphatic, blood vessel, pleural invasion or lymph node involvement (LY0V0PL0N0) regardless of stromal invasion.

RESULTS

Pathological assessments of specimens of 35 of 85 (41%) pure ground glass opacity tumors including 3 (23%) of 13 pure ground glass opacity tumors ≤ 1 cm, revealed partially invasive components. Receiver operating characteristic curves for LY0V0PL0N0 revealed solid tumor size ≤ 6 mm on high-resolution computed tomography or maximum standardized uptake values ≤ 0.6 on 2-[18F]fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography as radiographic indolent tumor criteria for predicting indolent tumors. Among 216 (35.5%) of 609 patients who met these criteria, none developed recurrence over a median follow-up of 41.6 months.

CONCLUSIONS

Pure ground glass opacity lesions on high-resolution computed tomography could pathologically include invasive components and would not correspond to adenocarcinoma in situ. Solid tumor size on high-resolution computed tomography and maximum standardized uptake values on positron emission tomography/computed tomography can predict indolent LY0V0PL0N0 lung tumors that can be followed up.

[Lung cancer screening. What have we learnt for the practice so far?]

CLINICAL/METHODICAL ISSUE

Lung cancer is the most frequent cause of tumor-associated death and only has a good prognosis if detected at a very early tumor stage.

METHODICAL INNOVATIONS

For the first time the American National Lung Screening Trial (NLST) could prove that low-dose computed tomography (CT) screening is able to reduce lung cancer mortality by 20 %.

PERFORMANCE

To date, however, three much smaller and therefore statistically underpowered European trials could not confirm the positive results of the NLST. The results of the largest European trial NELSON are expected within the next 2 years. In addition, there are a number of open or not yet satisfactorily answered questions, such as the definition of the appropriate screening population, the management of nodules detected by screening, the effects of over-diagnosis and the risk of cumulative radiation exposure.

PRACTICAL RECOMMENDATIONS

The success of the NLST prompted several predominantly American professional societies to issue a positive recommendation about the implementation of lung cancer screening in a population at risk. However, potentially conflicting results of European studies and a number of not yet optimized issues justify caution and call for a pooled analysis of European studies in order to provide statistically sound results and to ensure a high efficiency of screening with respect to the radiation applied, mental and physical patient burden and, last but not least, the financial efforts.

Reclassification of early stage pulmonary adenocarcinoma and its consequences

The classification of pulmonary adenocarcinoma has recently undergone several proposed changes. Among these, the most striking pertains to the discontinuation of the term "bronchioloalveolar carcinoma (BAC)" and its replacement by the terms "adenocarcinoma in situ (AIS)" or "minimally invasive adenocarcinoma (MIA)" for small solitary adenocarcinomas with either pure bronchiolalveolar growth or predominant bronchioloalveolar growth and ≤5 mm invasion, respectively, in resection specimens. The recommendation for these new concepts was based on discussion and review of the literature by a panel of experts from multiple disciplines. However, the results of a recent study investigating the topic of early stage adenocarcinoma (pT1N0M0) which was based on an actual series of cases, have raised questions as to the concept, validity and justification of such new terminology and have reinforced the need to evaluate actual cases that meet the newly proposed definitions and compare them in terms of patient outcome. This is even more important when proposing terminology that implies benign behavior and that could result in a false sense of security putting patients at risk for suboptimal treatment approaches. The controversies surrounding these issues are the subject of this work.