Ground-glass nodules of the lung in never-smokers and smokers: clinical and genetic insights

Application of 18 F-fluorodeoxyglucose PET/computed tomography in the diagnosis of infiltrative subsolid nodules in lung adenocarcinoma

PURPOSE

To investigate the diagnostic value of 18 F-fluorodeoxyglucose(FDG) PET/computed tomography (CT) for infiltrative subsolid nodules at different stages of lung adenocarcinoma and to explore predictive factors for invasive adenocarcinoma, providing compelling evidence for timely intervention.

METHODS

A retrospective analysis was conducted on PET/CT imaging data of 170 subsolid nodules lesions confirmed postoperatively as lung adenocarcinoma or precursor glandular lesions. Lesions were categorized into preinvasive lesions including atypical adenomatous hyperplasia and adenocarcinoma in situ, microinvasive adenocarcinoma, and invasive adenocarcinoma. Compared the differences in imaging features and metabolic parameters among different groups and used a multifactor logistic regression model and receiver operating characteristic curve analysis to identify predictive factors for invasive adenocarcinoma.

RESULTS

From preinvasive lesions through microinvasive adenocarcinoma to invasive adenocarcinoma, there was a gradual increase in nodule diameter, nodule area, and proportion of part-solid nodule. Statistical significance ( P  < 0.05) was observed in the rates of spiculation and pleural indentation between preinvasive lesions versus microinvasive adenocarcinoma and invasive adenocarcinoma groups. The maximum standardized uptake value and maximum standardized uptake ratio show statistically significant differences ( P  < 0.05) between the invasive adenocarcinoma group and the other groups. Logistic regression analysis indicated that nodule composition, nodule diameter, and maximum standardized uptake ratio were predictive factors for invasive adenocarcinoma ( P  < 0.05). For part-solid nodules, the longest diameter of the solid component has a high diagnostic value.

CONCLUSION

The imaging features of 18 F-FDG PET/CT contribute to the diagnosis of infiltrative subsolid nodules at different stages of lung adenocarcinoma, providing robust evidence for timely intervention.

Premalignant Progression in the Lung: Knowledge Gaps and Novel Opportunities for Interception of Non-Small Cell Lung Cancer. An Official American Thoracic Society Research Statement

Rationale: Despite significant advances in precision treatments and immunotherapy, lung cancer is the most common cause of cancer death worldwide. To reduce incidence and improve survival rates, a deeper understanding of lung premalignancy and the multistep process of tumorigenesis is essential, allowing timely and effective intervention before cancer development. Objectives: To summarize existing information, identify knowledge gaps, formulate research questions, prioritize potential research topics, and propose strategies for future investigations into the premalignant progression in the lung. Methods: An international multidisciplinary team of basic, translational, and clinical scientists reviewed available data to develop and refine research questions pertaining to the transformation of premalignant lung lesions to advanced lung cancer. Results: This research statement identifies significant gaps in knowledge and proposes potential research questions aimed at expanding our understanding of the mechanisms underlying the progression of premalignant lung lesions to lung cancer in an effort to explore potential innovative modalities to intercept lung cancer at its nascent stages. Conclusions: The identified gaps in knowledge about the biological mechanisms of premalignant progression in the lung, together with ongoing challenges in screening, detection, and early intervention, highlight the critical need to prioritize research in this domain. Such focused investigations are essential to devise effective preventive strategies that may ultimately decrease lung cancer incidence and improve patient outcomes.

Effects of pregabalin combined with tramadol/paracetamol on acute pain in patients with CT-guided puncture localization of pulmonary nodules

OBJECTIVE

To investigate the effects of pregabalin combined with tramadol/paracetamol on acute pain in patients with CT-guided puncture localization of pulmonary nodules.

MATERIALS AND METHODS

In this randomized, placebo-controlled and single-center study, 120 patients were allocated randomly to four groups: the control group (Group P), the pregabalin-placebo group (Group BP), the tramadol/paracetamol-placebo group (Group AP), and the pregabalin-tramadol/paracetamol group (Group AB). The primary outcome was the NRS (Numerical Rating Scale) score. Other outcomes included systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), pulse oxygen saturation (SpO2), the incidence of moderate to severe pain, the analgesia recovery ratio, the incidence of adverse drug reactions and patients' satisfaction.

RESULTS

No significant interaction was detected between the interventions (P = 0.752). The NRS score of the Taking pregabalin group and the Taking tramadol/paracetamol group were significantly lower than those of the Not-taking pregabalin group and the Not-taking tramadol/paracetamol group respectively (P < 0.05). There was significant difference in the NRS scores among the four groups (P < 0.001). The NRS score of Group AB was significantly lower than that of Group P (P < 0.001), Group BP (P < 0.001) and Group AP (P = 0.001). At the same time, the NRS scores of Group BP (P < 0.001) and Group AP (P < 0.001) were significantly lower than those of Group P, but there was no significant difference between Group BP and Group AP (P = 1.000). The SBP, DBP, HR, the incidence of moderate to severe pain and the analgesia recovery ratio of Group AB were significantly lower than those of Group P (P < 0.05), while the SpO2 and the number of people who were very satisfied were significantly higher than those of Group P (P < 0.05). There was no significant difference in the incidence of adverse drug reactions among the four groups (P = 0.272).

CONCLUSIONS

The combination or single use of pregabalin and tramadol/paracetamol can effectively relieve the acute pain after localization. Pregabalin combined with tramadol/paracetamol has the best analgesic effect and significantly reduces the hemodynamic fluctuations, with high safety and low incidence of adverse drug reactions, which has a certain clinical popularization and application value.

Multi-omics analysis unveils immunosuppressive microenvironment in the occurrence and development of multiple pulmonary lung cancers

Multiple pulmonary lung cancers (MPLCs) are frequently encountered on computed tomography (CT) scanning of chest, yet their intrinsic characteristics associated with genomic features and radiological or pathological textures that may lead to distinct clinical outcomes remain largely unexplored. A total of 27 pulmonary nodules covering different radiological or pathological textures as well as matched adjacent normal tissues and blood samples were collected from patients diagnosed with MPLCs. Whole-exome sequencing (WES) and whole-transcriptome sequencing were performed. The molecular and immune features of MPLCs associated with distinct radiological or pathological textures were comprehensively investigated. Genomics analysis unveiled the distinct branches of pulmonary nodules originating independently within the same individual. EGFR and KRAS mutations were found to be prevalent in MPLCs, exhibiting mutual exclusivity. The group with KRAS mutations exhibited stronger immune signatures compared to the group with EGFR mutations. Additionally, MPLCs exhibited a pronounced immunosuppressive microenvironment, which was particularly distinct when compared with normal tissues. The expression of the FDSCP gene was specifically observed in MPLCs. When categorizing MPLCs based on radiological or pathological characteristics, a progressive increase in mutation accumulation was observed, accompanied by heightened chromatin-level instability as ground-glass opacity component declined or invasive progression occurred. A close association with the immunosuppressive microenvironment was also observed during the progression of pulmonary nodules. Notably, the upregulation of B cell and regulatory T cell marker genes occurred progressively. Immune cell abundance analysis further demonstrated a marked increase in exhausted cells and regulatory T cells during the progression of pulmonary nodules. These results were further validated by independent datasets including nCounter RNA profiling, single-cell RNA sequencing, and spatial transcriptomic datasets. Our study provided a comprehensive representation of the diverse landscape of MPLCs originating within the same individual and emphasized the significant influence of the immunosuppressive microenvironment in the occurrence and development of pulmonary nodules. These findings hold great potential for enhancing the clinical diagnosis and treatment strategies for MPLCs.

Correlation of CT features of lung adenocarcinoma with sex and age

This study aimed to retrospectively examine the computed tomography (CT) features of lung adenocarcinoma across different demographic groups. Preoperative chest CT findings from 1266 surgically resected lung adenocarcinoma cases were retrospectively analyzed. Lung adenocarcinomas were categorized based on CT characteristics into pure ground glass (pGGO), nodule-containing ground glass opacity (mGGO), and pure solid without containing ground glass opacity (pSD). These categories were correlated with sex, age, EGFR status, and five histopathological subtypes. The diameters of pGGO, mGGO, and pSD significantly increased across all patient groups (P < 0.05). Males exhibited a significantly higher proportion of pSD than females (P = 0.002). The mean diameters of pGGO and pSD were significantly larger in males than in females (P = 0.0017 and P = 0.043, respectively). The frequency of pGGO was higher in the younger age group (≤ 60 years) compared to the older group (> 60 years) for both males (P = 0.002) and females (P = 0.027). The frequency of pSD was higher in the older age group for both sexes. A linear correlation between age and diameter was observed in the entire cohort as well as in the male and female groups (P < 0.0001 for all groups). EGFR mutations were less frequent in pSD compared to pGGO (P = 0.0002) and mGGO (P < 0.0001). The frequency of lesions containing micropapillary components increased from pGGO to mGGO and pSD (P < 0.0001 for all). The frequency of lesions containing solid components also increased from pGGO to mGGO and pSD (P = 0.045, P < 0.0001, and P < 0.0001, respectively). The CT features of lung adenocarcinoma exhibit differences across genders and age groups. Male gender and older age are risk factors for lung adenocarcinoma growth.

Integrated whole-exome and bulk transcriptome sequencing delineates the dynamic evolution from preneoplasia to invasive lung adenocarcinoma featured with ground-glass nodules

OBJECTIVE

The genomic and molecular ecology involved in the stepwise continuum progression of lung adenocarcinoma (LUAD) from adenocarcinoma in situ (AIS) to minimally invasive adenocarcinoma (MIA) and subsequent invasive adenocarcinoma (IAC) remains unclear and requires further elucidation. We aimed to characterize gene mutations and expression landscapes, and explore the association between differentially expressed genes (DEGs) and significantly mutated genes (SMGs) during the dynamic evolution from AIS to IAC.

METHODS

Thirty-five patients with ground-glass nodules (GGNs) lung adenocarcinomas were enrolled. Whole-exome sequencing (WES) and transcriptome sequencing (RNA-Seq) were conducted on all patients, encompassing both tumor samples and corresponding noncancerous tissues. Data obtained from WES and RNA-Seq were subsequently analyzed.

RESULTS

The findings from WES delineated that the predominant mutations were observed in EGFR (49%) and ANKRD36C (17%). SMGs, including EGFR and RBM10, were associated with the dynamic evolution from AIS to IAC. Meanwhile, DEGs, including GPR143, CCR9, ADAMTS16, and others were associated with the entire process of invasive LUAD. We found that the signaling pathways related to cell migration and invasion were upregulated, and the signaling pathways of angiogenesis were downregulated across the pathological stages. Furthermore, we found that the messenger RNA (mRNA) levels of FAM83A, MAL2, DEPTOR, and others were significantly correlated with CNVs. Gene set enrichment analysis (GSEA) showed that heme metabolism and cholesterol homeostasis pathways were significantly upregulated in patients with EGFR/RBM10 co-mutations, and these patients may have poorer overall survival than those with EGFR mutations. Based on the six calculation methods for the immune infiltration score, NK/CD8+ T cells decreased, and Treg/B cells increased with the progression of early LUAD.

CONCLUSIONS

Our findings offer valuable insights into the unique genomic and molecular features of LUAD, facilitating the identification and advancement of precision medicine strategies targeting the invasive progression of LUAD from AIS to IAC.

[Hypothesis of Genetic Diversity Selection in the Occurrence and Development of Lung Cancer: Molecular Evolution and Clinical Significance]

So far, the monoclonal hypothesis of tumor occurrence and development cannot be justified. The genetic diversity selection hypothesis for the occurrence and development of lung cancer links Mendelian genetics with Darwin's theory of evolution, suggesting that the genetic diversity of tumor cell populations with polyclonal origins-monoclonal selection-subclonal expansion is the result of selection pressure. Normal cells acquire mutations in oncogenic driver genes and have a selective advantage over other cells, becoming tumor initiating cells; In the interaction with the tumor microenvironment (TME), the vast majority of initiating cells are recognized and killed by the human immune system. If immune escape occurs, the incidence of malignant tumors will greatly increase, and subclonal expansion, intratumour heterogeneity, etc. will occur. This article proposed the hypothesis of genetic diversity selection and analyzed its clinical significance.
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Enhancing the prediction of the invasiveness of pulmonary adenocarcinomas presenting as pure ground-glass nodules: Integrating intratumor heterogeneity score with clinical-radiological features via machine learning in a multicenter study

Objective

The invasiveness of lung adenocarcinoma significantly impacts clinical decision-making. However, assessing this invasiveness preoperatively, especially when it manifests as pure ground-glass nodules (pGGN) on CT scans, poses challenges. This study aims to quantify intratumor heterogeneity (ITH) and determine whether the ITH score can enhance the accuracy of invasiveness predictions.

Methods

A total of 524 patients with lung adenocarcinomas presenting as pGGN were enrolled in the study, with 177 (33.78%) receiving a pathologic diagnosis of invasiveness. Four diagnostic approaches were developed to predict the invasiveness of lung adenocarcinoma presenting as pGGN: (1) conventional lesion size, (2) ITH score, (3) clinical-radiological features (ClinRad), and (4) integration of the ITH score with ClinRad. ClinRad alone or in combination with the ITH score served as the input for 11 machine learning approaches. The trained models were evaluated in an independent validation cohort, and the area under the curve (AUC) was calculated to assess classification performance.

Results

The conventional lesion size showed the lowest performance, with an AUC of 0.826 (95% confidence interval [CI]: 0.758-0.894), while the ITH score outperformed it with an AUC of 0.846 (95% CI: 0.787-0.905). The CatBoost model performed best when the ITH score and ClinRad were both used as input features, leading to the development of an ITH-ClinRad-guided CatBoost classifier. CatBoost also excelled with ClinRad alone, resulting in a ClinRad-guided CatBoost classifier with an AUC of 0.830 (95% CI: 0.764-0.896), surpassed by the ITH-ClinRad-guided CatBoost classifier with an AUC of 0.871 (95% CI: 0.818-0.924).

Conclusion

The ITH-ClinRad-guided CatBoost classifier emerges as a promising tool with significant potential to revolutionize the management of lung adenocarcinomas presenting as pGGNs.

Invasiveness identification in pure ground-glass nodules: exploring the generalizability of radiomics based on external validation and stress testing

PURPOSE

This study aimed to apply external validation and stress tests to evaluate the generalizability of radiomics models built using various machine-learning methods for identifying the invasiveness of lung adenocarcinomas manifesting as pure ground-glass nodules (pGGNs).

METHODS

This retrospective study enrolled 495 patients (514 pGGNs) confirmed as lung adenocarcinomas by postoperative pathology from three centers. All nodules were included in the primary cohort (randomly divided into training and test cohorts), two external validation cohorts, and two stress test cohorts. Six machine-learning radiomics models were constructed in the training cohort using the optimal features. Performance of radiomics models and clinical models were compared in primary cohort and external validation cohorts. The stress tests included stratified performance evaluation and shifted performance evaluation and contrastive evaluation under three single-condition modification settings. The predictive performance was validated by area under curve (AUC) of receiver operating characteristic (ROC).

RESULTS

Of the six radiomics models, the best logistic regression (LR) model was able to maintain high differential diagnostic capability (AUC: 0.849 ± 0.049) and good stability (relative standard deviation, 5.719%), but it showed poorer performance (AUC = 0.835) than the clinical model (AUC = 0.862) in the external validation cohort E1. The stress tests suggested LR model had no significant difference in performance between subgroups after stratification and had good consistency in the predictions before and after the three transformations (Kappa = 0.960, 0.840, and 0.933, respectively; p < 0.05, all).

CONCLUSION

The rigorous testing procedure facilitates the selection of high-performance radiomics models with good clinical generalizability.

Comparative genomics between matched solid and lepidic portions of semi-solid lung adenocarcinomas

BACKGROUND

Genetic changes that drive the transition from lepidic to invasive cancer development within a radiographic ground glass or semi-solid lung lesion (SSL) are not well understood. Biomarkers to predict the transition to solid, invasive cancer within SSL are needed.

METHODS

Patients with surgically resected SSL were identified retrospectively from a surgical database. Clinical characteristics and survival were compared between stage I SSL (n = 65) and solid adenocarcinomas (n = 120) resected during the same time period. Areas of normal lung, in situ lepidic, and invasive solid tumor were microdissected from within the same SSL specimens and next generation sequencing (NGS) and Affymetrix microarray of gene expression were performed.

RESULTS

There were more never smokers, Asian patients, and sub-lobar resections among SSL but no difference in 5-year survival between SSL and solid adenocarcinoma. Driver mutations found in both lepidic and solid invasive portion were EGFR (43%), KRAS (21%), and DNMT3A (5%). CEACAM5 was the most upregulated gene found in solid, invasive portions of SSL. Lepidic and invasive solid areas had many similarities in gene expression, however there were some significant differences with the gene SPP1 being a unique biomarker for the invasive component of a SSL.

CONCLUSIONS

Common lung cancer driver mutations are present in in situ lepidic as well as invasive solid portions of a SSL, suggesting early development of driver mutations. CEACAM5 and SPP1 emerged as promising biomarkers of invasive potential in semi-solid lesions. Other studies have shown both genes to correlate with poor prognosis in lung cancer and their role in evolution of semi-solid lung lesions warrants further study.

Plasma metabolomics study in screening and differential diagnosis of multiple primary lung cancer

BACKGROUND

Multiple primary lung cancer (MPLC) is becoming increasingly common in clinical practice. Imaging examination is sometimes difficult to differentiate from intrapulmonary metastasis (IM) or single primary lung cancer (SPLC) before surgery. There is a lack of effective blood biomarkers as an auxiliary diagnostic method.

PARTICIPANTS AND METHODS

A total of 179 patients who were hospitalized and operated in our department from January to June 2019 were collected, and they were divided into SPLC with 136 patients, MPLC with 24 patients, and IM with 19 patients. In total, 96 healthy people without lung cancer were enrolled. Medical history, imaging, and pathology data were assembled from all participants. Plasma metabolomics analysis was performed by quadrupole time-of-flight tandem mass spectrometry, and data were analyzed using SPSS19.0/Simca 14.1/MetaboAnalyst5.0 software. Significant metabolites were selected by variable importance in projection, P value, and fold change. The area under the receiver operating characteristic curve was used to evaluate their diagnostic ability.

RESULTS

There were significant differences in plasma metabolite profiles between IM and MPLC. Seven metabolites were screened out. Two metabolites had higher levels in IM, and five metabolites had higher levels in MPLC. All had favorable discriminating capacity. Phosphatidyl ethanolamine (38:5) showed the highest sensitivity (0.95) and specificity (0.92). It was followed by l -histidine with sensitivity 0.92 and specificity 0.84. l -tyrosine can be used to identify SPLC and MPLC. The panel composed of related metabolites exhibited higher diagnostic ability. Eight principal metabolites caused remarkable differences between healthy people and MPLC, and five of them had area under the curves greater than 0.85, showing good discriminating power.

CONCLUSION

Through the study of plasma metabolomics, it was found that there were obvious differences in the metabolite profiles of MPLC, IM, SPLC, and the healthy population. Some discovered metabolites possessed excellent diagnostic competence with high sensitivity and specificity. They had the potential to act as biomarkers for the screening and differential diagnosis of MPLCs.

Quantitative evaluation of density variability in the lesion-lung boundary zone to differentiate pulmonary subsolid nodules

Background

Transition of the CT values from nodule to peripheral normal lung is related to pathological changes and may be a potential indicator for differential diagnosis. This study investigated the significance of the standard deviation (SD) values in the lesion-lung boundary zone when differentiating between benign and neoplastic subsolid nodules (SSNs).

Methods

From January 2012 to July 2021, a total of 229 neoplastic and 84 benign SSNs confirmed by pathological examination were retrospectively and nonconsecutively enrolled in this study. The diagnostic study was not registered with a clinical trial platform, and the study protocol was not published. Computed tomography (CT) values of the ground-glass component (CT1), adjacent normal lung tissue (CT2), and lesion-lung boundary zone (CT3) were measured consecutively. The SD of CT3 was recorded to assess density variability. The CT1, CT2, CT3, and SD values were compared between benign and neoplastic SSNs.

Results

No significant differences in CT1 and CT2 were observed between benign and neoplastic SSNs (each P value >0.05). CT3 (-736.1±51.0 vs. -792.6±73.9; P<0.001) and its SD (135.6±29.6 vs. 83.6±20.6; P<0.001) in neoplastic SSNs were significantly higher than those in benign SSNs. Moreover, the SD increased with the invasiveness degree of neoplastic SSNs (r=0.657; P<0.001). The receiver operating characteristic (ROC) curve revealed that the area under the curve was 0.927 (95% CI: 0.896-0.959) when using the SD (cutoff value =106.98) as a factor to distinguish SSNs, which increased to 0.966 (95% CI: 0.934-0.985) when including nodules with a CT1 of ≥-715 Hounsfield units (HU) only (cutoff of SD 109.9, sensitivity 0.930, and specificity 0.914).

Conclusions

The SD as an objective index is valuable for differentiating SSNs, especially for those with a CT1 of ≥-715 HU, which have a higher possibility of neoplasm if the SD is >109.9.

Comprehensive characterization of genomic and radiologic features reveals distinct driver patterns of RTK/RAS pathway in ground-glass opacity pulmonary nodules

Ground-glass opacity (GGO)-associated pulmonary nodules have been known as a radiologic feature of early-stage lung cancers and exhibit an indolent biological behavior. However, the correlation between driver genes and radiologic features as well as the immune microenvironment remains poorly understood. We performed a custom 1021-gene panel sequencing of 334 resected pulmonary nodules presenting as GGO from 262 Chinese patients. A total of 130 multiple pulmonary nodules were sampled from 58 patients. Clinical-pathologic and radiologic parameters of these pulmonary nodules were collected. Immunohistochemistry (IHC) and multiplex immunofluorescent staining (mIF) were applied to analyze proliferation and immune cell markers of GGO-associated pulmonary nodules. Compared with pure GGO nodules, mixed GGO nodules were enriched for invasive adenocarcinoma (IAC) (182/216 vs 73/118, P &lt; .001). Eighty-eight percent (294/334) of GGO-associated nodules carried at least one mutation in EGFR/ERBB2/BRAF/KRAS/MAP2K1 of the RTK/RAS signaling pathway, and the alterations in these driver genes were mutually exclusive. The analysis of multifocal pulmonary nodules from the same patient revealed evidence of functional convergence on RTK/RAS pathways. Nodules with ERBB2/BRAF/MAP2K1 mutations tended to be more indolent than those with EGFR and KRAS mutations. IHC and mIF staining showed that KRAS-mutant GGO nodules displayed higher infiltration of CD4+ T cell and CD8+ T cell as well as stronger proliferation and immune inhibitory signals. Our study demonstrates a driver landscape of radiologically detectable GGO-associated pulmonary nodules in Chinese patients and supports that different driver patterns in RTK/RAS pathway are corresponding to different radiologic features.

Clinical and radiomic factors for predicting invasiveness in pulmonary ground‑glass opacity

Patients with preinvasive or invasive pulmonary ground-glass opacity (GGO) often face different clinical treatments and prognoses. The present study aimed to identify the invasiveness of pulmonary GGO by analysing clinical and radiomic features. Patients with pulmonary GGOs who were treated between January 2014 and February 2019 were included. Clinical features were collected, while radiomic features were extracted from computed tomography records using the three-dimensional Slicer software. Predictors of GGO invasiveness were selected by least absolute shrinkage and selection operator logistic regression analysis, and receiver operating characteristic (ROC) curves were drawn for each prediction model. A total of 194 patients with pulmonary GGOs were included in the present study. The maximum diameter of the solid component, waveletHLL_ngtdm_Coarseness (P=0.03), waveletLHH_firstorder_Maximum (P<0.01) and waveletLLH_glrlm_LongRunEmphasis (P<0.01) were significant predictors of invasive lung GGOs. The area under the ROC curve (AUC) for the prediction models of clinical features and radiomic features was 0.755 and 0.719, respectively, whereas the AUC for the combined prediction model was 0.864 (95% CI, 0.802-0.926). Finally, a nomogram was established for individualized prediction of invasiveness. The combination of radiomic and clinical features can enable the differentiation between preinvasive and invasive GGOs. The present results can provide some basis for the best choice of treatment in patients with lung GGOs.

Adding predictive and diagnostic values of pulmonary ground-glass nodules on lung cancer via novel non-invasive tests

Pulmonary ground-glass nodules (GGNs) are highly associated with lung cancer. Extensive studies using thin-section high-resolution CT images have been conducted to analyze characteristics of different types of GGNs in order to evaluate and determine the predictive and diagnostic values of GGNs on lung cancer. Accurate prediction of their malignancy and invasiveness is critical for developing individualized therapies and follow-up strategies for a better clinical outcome. Through reviewing the recent 5-year research on the association between pulmonary GGNs and lung cancer, we focused on the radiologic and pathological characteristics of different types of GGNs, pointed out the risk factors associated with malignancy, discussed recent genetic analysis and biomarker studies (including autoantibodies, cell-free miRNAs, cell-free DNA, and DNA methylation) for developing novel diagnostic tools. Based on current progress in this research area, we summarized a process from screening, diagnosis to follow-up of GGNs.

Impact of a Ground-glass Opacity Component on c-Stage IA Lung Adenocarcinoma

Studies have shown that tumors with ground-glass opacity (GGO) components are associated with favorable outcomes. However, this view should be confirmed in an international cohort. We aimed to verify the impact of a GGO component on clinical (c)-stage IA lung adenocarcinoma and to describe the biological discrepancies between the part-solid and pure-solid groups. We evaluated 1333 cases of surgically resected c-stage IA lung adenocarcinomas, including 484 part-solid and 849 pure-solid tumors. Furthermore, we matched the solid size between the 2 groups and examined 470 patients. We compared the prognoses between the 2 groups before and after matching. The prognostic and biological differences were described before and after matching. Compared with the pure-solid group, the part-solid group was associated with favorable outcomes [5-year overall survival (OS) 99.4% vs 87.6%, P < 0.001; 5-year recurrence-free survival (RFS) 96.9% vs 82.2%, P < 0.001]. Similar results were obtained after matching (5-year OS 98.9% vs 92.2%, P = 0.012; 5-year RFS 95.0% vs 88.5%, P = 0.007). Multivariable analyses revealed that GGO component appearance was a factor of better OS and RFS. The part-solid tumor, regardless of the size of the solid component, had a similar outcome to the pure-solid tumor of c-stage T1a classification. Also, more epidermal growth factor receptor, human epidermal growth factor receptor-2 mutations, and receptor tyrosine kinase ROS-1-positive were observed in the part-solid group. In comparison, more wild types and Kirsten-Ras were observed in the pure-solid group. Adenocarcinomas with a GGO component were associated with superior outcomes. The GGO component should be considereda new clinical T descriptor. Early-stage lung adenocarcinomas with and without a GGO component may be 2 distinct tumor types.

A Machine-Learning Approach to Developing a Predictive Signature Based on Transcriptome Profiling of Ground-Glass Opacities for Accurate Classification and Exploring the Immune Microenvironment of Early-Stage LUAD

Screening for early-stage lung cancer with low-dose computed tomography is recommended for high-risk populations; consequently, the incidence of pure ground-glass opacity (pGGO) is increasing. Ground-glass opacity (GGO) is considered the appearance of early lung cancer, and there remains an unmet clinical need to understand the pathology of small GGO (&lt;1 cm in diameter). The objective of this study was to use the transcriptome profiling of pGGO specimens &lt;1 cm in diameter to construct a pGGO-related gene risk signature to predict the prognosis of early-stage lung adenocarcinoma (LUAD) and explore the immune microenvironment of GGO. pGGO-related differentially expressed genes (DEGs) were screened to identify prognostic marker genes with two machine learning algorithms. A 15-gene risk signature was constructed from the DEGs that were shared between the algorithms. Risk scores were calculated using the regression coefficients for the pGGO-related DEGs. Patients with Stage I/II LUAD or Stage IA LUAD and high-risk scores had a worse prognosis than patients with low-risk scores. The prognosis of high-risk patients with Stage IA LUAD was almost identical to that of patients with Stage II LUAD, suggesting that treatment strategies for patients with Stage II LUAD may be beneficial in high-risk patients with Stage IA LUAD. pGGO-related DEGs were mainly enriched in immune-related pathways. Patients with high-risk scores and high tumor mutation burden had a worse prognosis and may benefit from immunotherapy. A nomogram was constructed to facilitate the clinical application of the 15-gene risk signature. Receiver operating characteristic curves and decision curve analysis validated the predictive ability of the nomogram in patients with Stage I LUAD in the TCGA-LUAD cohort and GEO datasets.

[Clinical Characteristics and Risk Factors Analysis for Visceral Pleural Invasion in Mixed Ground-glass Nodular Lung Adenocarcinoma]

BACKGROUND

Lung cancer is still the malignant tumor with the highest morbidity and mortality in China. Lung adenocarcinoma is the most common subtype, and the number of lung cancer presenting as mixed ground glass nodule (mGGN) in imaging is gradually increasing. Visceral pleural invasion (VPI) is an important factor affecting the prognosis of mGGN type lung adenocarcinoma. The aim of the study is to explore and analyze the risk factors for VPI in mGGN type lung adenocarcinoma.

METHODS

From November 2016 to November 2019, 128 patients with mGGN lung adenocarcinoma underwent radical surgical resection in the First Affiliated Hospital of Nanjing Medical University. Their clinical data, including imaging, pathological and biological features, were collected and analyzed retrospectively. There were 40 males and 88 females, aged 60.3±9.3 years ranging from 30 to 81 years. Single factor Chi-square test and multivariate Logistic regression were used to analyze the risk factors of VPI in mGGN type lung adenocarcinoma.

RESULTS

Among 128 mGGN patients who met the inclusion criteria, 57 cases were pathologically confirmed with pleural invasion. Between the VPI (+) and VPI (-) group (P<0.05), there were significant differences in gender, maximum diameter of solid component, consolidation tumor ratio (CTR), spicule sign, history of lung disease, family history of hypertension, relation of lesion to pleura (RLP), coursing relationship between bronchi and nodules. In multivariate Logistic regression analysis, RLP (OR=3.529, 95%CI: 1.430-8.713, P=0.006) and coursing relationship between bronchi and nodules (OR=3.993, 95%CI: 1.517-10.51, P=0.005) were found to be independent risk factors for VPI (P<0.05).

CONCLUSIONS

The possibility of VPI in m GGN lung adenocarcinoma should be evaluated by combining these parameters in clinical diagnosis and treatment. As independent risk factors, RLP and coursing relationship between bronchi and nodules are instructive to identify VPI in mGGN type lung adenocarcinoma.

Differential Diagnosis of Nonabsorbable Inflammatory and Malignant Subsolid Nodules with a Solid Component ≤5 mm

Purpose

To investigate the differential clinical and computed tomography (CT) characteristics of pulmonary nonabsorbable inflammatory and malignant subsolid nodules (SSNs) with a solid component ≤5 mm.

Patients and Methods

We retrospectively analyzed 576 consecutive patients who underwent surgical resection and had SSNs with a solid component ≤5 mm on CT images. These patients were divided into inflammatory and malignant groups according to pathology. Their clinical and imaging data were analyzed and compared. Multiple logistic regression analysis was used to identify independent prognostic factors differentiating inflammatory from malignant SSNs. Furthermore, 146 consecutive patients were included as internal validation cohort to test the prediction efficiency of this model.

Results

Significant differences in 11 clinical characteristics and CT features were found between both groups (P < 0.05). Presence of respiratory symptoms, distribution of middle/lower lobe, irregular shape, part-solid nodule (PSNs), CT value of ground-glass opacity (GGO) areas <−657 Hu, presence of abnormal intra-nodular vessel sign, and interlobular septal thickening were the most effective factors for diagnosing nonabsorbable inflammatory SSNs, with an AUC (95% CI), accuracy, sensitivity, and specificity of 0.843 (95% CI: 0.811–0.872), 89.76%, 72.86%, and 81.23%, respectively. The internal validation cohort obtained an AUC (95% CI), accuracy, sensitivity, and specificity of 0.830 (95% CI: 0.759–0.887), 83.56%, 73.91%, and 76.42%, respectively.

Conclusion

Nonabsorbable inflammatory and malignant SSNs with a solid component ≤5 mm exhibited different clinical and imaging characteristics.

Invasive Prediction of Ground Glass Nodule Based on Clinical Characteristics and Radiomics Feature

Objective: To explore the diagnostic value of CT radiographic images and radiomics features for invasive classification of lung adenocarcinoma manifesting as ground-glass nodules (GGNs) in computer tomography (CT).

Methods: A total of 312 GGNs were enrolled in this retrospective study. All GGNs were randomly divided into training set (n = 219) and test set (n = 93). Univariate and multivariate logistic regressions were used to establish a clinical model, while the minimum redundancy maximum relevance (mRMR) and least absolute shrinkage and selection operator (LASSO) algorithm were used to select the radiomics features and construct the radiomics model. A combined model was finally built by combining these two models. The performance of these models was assessed in both training and test set. A combined nomogram was developed based on the combined model and evaluated with its calibration curves and C-index.

Results: Diameter [odds ratio (OR), 1.159; p ＜ 0.001], lobulation (OR, 2.953; p = 0.002), and vascular changes (OR, 3.431; p ＜ 0.001) were retained as independent predictors of the invasive adenocarcinoma (IAC) group. Eleven radiomics features were selected by mRMR and LASSO method to established radiomics model. The clinical model and radiomics mode showed good predictive ability in both training set and test set. When two models were combined, the diagnostic area under the curve (AUC) value was higher than the single clinical or radiomics model (training set: 0.86 vs. 0.83 vs. 0.82; test set: 0.80 vs. 0.78 vs. 0.79). The constructed combined nomogram could effectively quantify the risk degree of 3 image features and Rad score with a C-index of 0.855 (95%: 0.805∼0.905).

Conclusion: Radiographic and radiomics features show high accuracy in the invasive diagnosis of GGNs, and their combined analysis can improve the diagnostic efficacy of IAC manifesting as GGNs. The nomogram, serving as a noninvasive and accurate predictive tool, can help judge the invasiveness of GGNs prior to surgery and assist clinicians in creating personalized treatment strategies.

Pan-Driver-Negatives <i>versus</i> Epidermal Growth Factor Receptor Mutants for C-Stage IA Lung Adenocarcinoma with Ground-Glass Opacity

Purpose: We aimed to verify the prognosis of epidermal growth factor receptor (EGFR) mutation of clinical (c)-stage IA lung adenocarcinoma with the ground-glass opacity (GGO) component.

Methods: We evaluated 226 cases of surgically resected c-stage IA lung adenocarcinoma with GGO component. Endpoints were overall survival (OS) and recurrence-free survival (RFS). Kaplan–Meier analysis and the log-rank test were used to estimate the survival differences. Prognostic factors were assessed using the univariable and multivariable Cox proportional hazards model.

Results: Among the 226 cases, 177 cases harbored the EGFR-mutant adenocarcinoma with the GGO component. The mean duration of follow-up time was 54.4 ± 1.2 months. The 5-year OS and RFS did not differ significantly between the EGFR-mutant and wild-type groups (5-year OS 100% vs. 94.3%, hazard ratio [HR] 0.276, P = 0.168; 5-year RFS 94.7% vs. 95.7%, HR 0.873, P = 0.864). Multivariable Cox hazard model revealed that radiologically solid component size (P = 0.010) and pathological node-positive (P = 0.036) were significant predictors of an inferior RFS.

Conclusion: EGFR-mutant was not a prognostic factor of OS and RFS for c-stage IA lung adenocarcinoma with the GGO component. Radiologically solid component size and pathological lymph node status were independent prognostic factors of worse RFS.

Selection Strategies and Practical Application of BRAF V600E-mutated Non-Small Cell Lung Carcinoma

Purpose

The incidence of BRAF V600E mutation in non–small cell lung carcinoma (NSCLC) is lower than 2%, which poses difficulties in finding legitimate patients for targeted therapy. We investigated the predictive factors pertaining to BRAF V600E and the effectiveness of the VE1 antibody as a screening method for patient selection.

Materials and Methods

The study was designed into two steps. In a first group, BRAF-mutated NSCLCs were identified from sequencing data to determine the features of BRAF V600E mutation. The results of the first group helped the collection of adenocarcinomas with a papillary or micropapillary pattern but without epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) alterations as a second group so that the frequency of BRAF V600E mutation could be calculated. The sensitivity and specificity of the VE1 were compared with BRAF V600E status.

Results

Among 39 BRAF-mutated NSCLCs in the first group, 20 (51%) were V600E. BRAF V600E mutation was more common in female patients and showed no significant correlation with smoking status. Nineteen cases were adenocarcinomas without EGFR and ALK alterations. The most common patterns of invasion were papillary and micropapillary along with central fibrosis. The sensitivity and specificity of the VE1 were 90.0% and 92.3%, respectively. In the second group, 6.7% of cases were VE1-positive, indicating that the prevalence was significantly higher than that reported in previous studies (0.3%–1.8%).

Conclusion

BRAF V600E-mutated NSCLCs could be enriched with the application of clinicopathologic parameters, which are not perfect. Therefore, additional VE1 immunohistochemistry may be useful as a screening method.

Natural Progression of Ground-glass Nodules after Curative Resection for Non-small Cell Lung Cancer

BACKGROUND

This retrospective study investigated the natural course of synchronous ground-glass nodules (GGNs) that remained after curative resection for non-small-cell lung cancer (NSCLC).

METHODS

Prospectively collected retrospective data were reviewed concerning 2,276 patients who underwent curative resection for NSCLC between 2008 and 2017. High-resolution computed tomography or thin-section computed tomography data of 82 patients were included in the study. Growth in size was considered the most valuable outcome, and patients were grouped according to GGN size change. Patient demographic data (e.g., age, sex, and smoking history), perioperative data (e.g., GGN characteristics, histopathology and pathological stage of the resected tumours), and other medical history were evaluated in a risk factor analysis concerning GGN size change.

RESULTS

The median duration of follow-up was 36.0 months (interquartile range, 23.0-59.3 months). GGN size decreased in 6 patients (7.3%), was stationary in 43 patients (52.4%), and increased in 33 patients (40.2%). In univariate analysis, male sex, the GGN size on initial CT, part-solid GGN and smoking history (≥ 10 pack-years) were significant risk factors. Among them, multivariate analysis revealed that lager GGN size, part-solid GGN and smoking history were independent risk factors.

CONCLUSION

During follow-up, 40.2% of GGNs increased in size, emphasising that patients with larger GGNs, part-solid GGN or with a smoking history should be observed.

Lung cancer probability and clinical outcomes of baseline and new subsolid nodules detected on low-dose CT screening

BACKGROUND

Limited data are available regarding the management of subsolid nodules detected on lung cancer screening with low-dose CT (LDCT). We aimed to determine the characteristics of screen-detected subsolid nodules, and to evaluate the probability of lung cancer and the clinical course of subsolid nodules detected at baseline and during follow-up screening.

METHODS

We evaluated 50 132 asymptomatic adults (22 631 never-smokers and 27 501 ever-smokers) who underwent LDCT screening for lung cancer between May 2003 and June 2019 at a tertiary centre in South Korea. The incidence, characteristics and clinical outcomes of the baseline and new screen-detected subsolid nodules were determined.

RESULTS

A total of 6725 subsolid nodules (5116 pure ground glass opacity nodules and 1609 part-solid nodules) were detected in 4545 participants (1484 new subsolid nodules detected in 937 (1.9%) participants; the overall incidence of subsolid nodules: 10.7% in never-smokers and 7.7% in ever-smokers, p<0.001). Among 4918 subsolid nodules that underwent follow-up with CT scans (the mean number of CT scans, including the baseline LDCT scan: 4.6), 2116 nodules (30.0% of baseline subsolid nodules and 78.9% of new subsolid nodules) resolved spontaneously. Among 293 biopsied subsolid nodules, 227 (77.5%) nodules were diagnosed as lung cancer, of which 226 (99.6%) were adenocarcinomas. No significant difference was observed in pathological invasiveness or the initial stage between the baseline and new cancerous subsolid nodules. Multivariable analyses revealed that new detection at follow-up screening was significantly associated with a lower probability of lung cancer (OR 0.26, 95% CI 0.14 to 0.49) and overall growth (OR 0.39, 95% CI 0.26 to 0.59), but with a higher probability of resolution (OR 6.30, 95% CI 5.09 to 7.81).

CONCLUSIONS

LDCT screening led to a considerably high rate of subsolid nodule detection, particularly in never-smokers. Compared with the baseline subsolid nodules, the new subsolid nodules were associated with a lower probability of lung cancer and higher probability of spontaneous resolution, indicating their more inflammatory nature. Less aggressive follow-up may be allowed for new subsolid nodules, particularly in screening programmes for Asian populations.

Adenocarcinoma spectrum lesions of the lung: Detection, pathology and treatment strategies

Adenocarcinoma has become the most prevalent lung cancer sub-type and its frequency is increasing. The earliest stages in the development of lung adenocarcinomas are visible using modern computed tomography (CT) as ground glass nodules. These pre-invasive nodules can progress over time to become invasive lung adenocarcinomas. Lesions in this developmental pathway are termed 'adenocarcinoma spectrum' lesions. With the introduction of lung cancer screening programs there has been an increase in the detection of these lesions raising questions about natural history, surveillance and treatment. Here we review how the radiological appearance of an adenocarcinoma spectrum lesion relates to its underlying pathology and explore the natural history and factors driving lesion progression. We examine the molecular changes that occur at each stage of adenocarcinoma spectrum lesion development, including the effects of the driver mutations, EGFR and KRAS, that are key to invasive adenocarcinoma pathology. A better understanding of the development of pre-invasive disease will create treatment targets. Our understanding of how tumours interact with the immune system has led to the development of new therapeutic strategies. We review the role of the immune system in the development of adenocarcinoma spectrum lesions. With a clear preinvasive phase there is an opportunity to treat early adenocarcinoma spectrum lesions before an invasive lung cancer develops. We review current management including surveillance, surgical resection and oncological therapy as well as exploring potential future treatment avenues.

Prognostic histologic subtyping of dominant tumor in resected synchronous multiple adenocarcinomas of lung

The prognostic role of histological patterns of dominant tumor (DT) and second dominant tumor (sDT) in synchronous multiple adenocarcinoma (SMADC) of lung remains unclear. SMADC patients diagnosed between 2003 and 2015 were retrospectively reviewed. DT and sDT were defined as two maximum diameters of consolidation among multiple tumors. Histological pattern was determined using IASLC/ATS/ERS classification system. DTs were divided into low- (lepidic), intermediate- (acinar, papillary) and high-grade (micropapillary, solid) subtypes, and sDTs into non-invasive predominant (lepidic) and invasive predominant (acinar, papillary, micropapillary, solid) subtypes. During mean 74-month follow-up among 149 nodal-negative patients having SMADC resected, recurrence was noted in 44 (29.5%), with significantly higher percentage in high-grade DT (p < 0.001). Five-year overall (OS) and disease-free (DFS) survivals in low-, intermediate- and high-grade DT were 96.9%, 94.3%, 63.3% (p < 0.001) and 100%, 87.2%, 30.0%, respectively (p < 0.001). Cox-regression multivariate analysis demonstrated high-grade DT as a significant predictor for DFS (Hazard ratio [HR] 5.324; 95% CI 2.570–11.462, p < 0.001) and OS (HR 3.287; 95% CI 1.323–8.168, p = 0.010). Analyzing DT and sDT together, we found no significant differences in DFS, either in intermediate- or high-grade DT plus invasive or non-invasive sDT. DT was histologically an independent risk factor of DFS and OS in completely resected nodal-negative SMADCs.

[Expert Consensus for Thermal Ablation of Pulmonary Subsolid Nodules (2021 Edition)]

局部热消融技术在肺部结节治疗领域正处在起步与发展阶段，为了肺结节热消融治疗的临床实践和规范发展，由“中国医师协会肿瘤消融治疗技术专家组”“中国医师协会介入医师分会肿瘤消融专业委员会”“中国抗癌协会肿瘤消融治疗专业委员会”“中国临床肿瘤学会消融专家委员会”组织多学科国内有关专家，讨论制定了“热消融治疗肺部亚实性结节专家共识（2021年版）”。主要内容包括：①肺部亚实性结节的临床评估；②热消融治疗肺部亚实性结节技术操作规程、适应证、禁忌证、疗效评价和相关并发症；③存在的问题和未来发展方向。

Low-dose chest computed tomographic screening and invasive diagnosis of pulmonary nodules for lung cancer in never-smokers

BACKGROUND

Although lung cancer screening using low-dose computed tomography (LDCT) is now widely used in clinical practice, the characteristics and outcomes of diagnostic procedures related to screen-detected nodules in never-smokers remain unclear. We aimed to determine the incidence of nodules considered for invasive biopsy and evaluate the final diagnoses and procedure-related complications in never-smokers in comparison to ever-smokers who underwent LDCT screening.

METHODS

We evaluated 37 436 asymptomatic adults (17 968 never-smokers and 19 468 ever-smokers) who underwent LDCT screening for lung cancer between January 2009 and December 2018 at a tertiary centre in South Korea. The rates of invasive diagnostic procedures for detected nodules and related complications, and the diagnostic outcomes were determined in the never-smoker and ever-smoker groups.

RESULTS

Among the never-smokers, 2908 (16.2%) out of 17 968 had positive nodules. Overall, 139 (0.77%) out of 17 968 never-smokers and 194 (1.00%) out of 19 468 ever-smokers underwent invasive biopsy (p=0.022). Lung cancer was diagnosed in 84 (0.47%) out of 17 968 never-smokers and 123 (0.63%) out of 19 468 ever-smokers (p=0.032). The proportions of participants diagnosed with benign disease after invasive biopsy (false-positive) were 50 (0.28%) out of 17 968 and 69 (0.35%) out of 19 468 in the never-smoker and ever-smoker groups, respectively (p=0.191). Multivariate analyses revealed no significant associations of smoking with the risk of a false-positive diagnosis (OR 0.98, 95% CI 0.62-1.57) and complications (OR 1.33, 95% CI 0.65-3.73) after biopsy. Of the 84 never-smokers with lung cancer, 82 (97.6%) had adenocarcinoma, and 75 (89.3%) were in stage I with a favourable prognosis.

CONCLUSIONS

LDCT screening in never-smokers resulted in a notable detection rate of lung nodules, which warranted invasive biopsy. The lung cancer detection rate was lower in never-smokers than in ever-smokers. However, no significant differences in the false-positive and complication rates were observed between the two groups. Accordingly, a more specifically tailored management strategy is needed for screen-detected nodules in Asian never-smokers.

Multiple Primary Lung Cancers: A New Challenge in the Era of Precision Medicine

With the widespread implementation of lung cancer screening, more and more patients are being diagnosed with multiple primary lung cancers (MPLCs). In the era of precision medicine, many controversies remain in differentiating MPLCs from intrapulmonary metastasis and the optimum treatment choice, especially in patients exhibiting similar histology. In this review, we summarize common diagnostic criteria and novel discrimination methods with a special emphasis on the emerging value of broad panel next-generation sequencing (NGS) for the diagnosis of MPLCs. We then discuss current advances regarding therapeutic approaches for MPLCs. Radical surgery is the main treatment modality, while stereotactic body radiotherapy (SBRT) is safe and feasible for early-stage MPLC patients with inoperable tumors. In addition, immunotherapy and targeted therapy, particularly epidermal growth factor receptor-tyrosine kinase inhibitors, are emerging therapeutic strategies that are still in their infancy. Characteristics of both genomic profiles and tumor microenvironment are currently being evaluated but warrant further exploration to facilitate the application of targeted systematic therapies in MPLC patients.

A pilot study of the ultrathin cryoprobe in the diagnosis of peripheral pulmonary ground-glass opacity lesions

Background

It is very difficult to obtain samples of peripheral pulmonary ground-glass opacity lesions (GGOs) by traditional transbronchial biopsy. This study was conducted to evaluate the diagnostic efficacy and safety of transbronchial cryobiopsy (TBCB) of GGOs using a newly developed ultrathin cryoprobe with an outer diameter of 1.1 mm.

Methods

We retrospectively analyzed 20 patients with 23 GGOs who underwent TBCB using the ultrathin cryoprobe from October 2018 to November 2019 in the Shanghai Chest Hospital. The TBCB procedure was performed under the guidance of virtual bronchoscopic navigation (VBN), electromagnetic navigation bronchoscopy (ENB), endobronchial ultrasound, and fluoroscopy. We collected the baseline information of participants, reported diagnostic yield and complications, and analyzed factors may have affected the diagnostic yield.

Results

A total of 23 GGOs (12 pure GGOs, 11 mixed GGOs), with an average diameter of 21.58±11.88 mm, underwent TBCB, and the diagnostic yield was 82.61% (19/23). Of the 19 GGOs diagnosed by TBCB, 12 were adenocarcinomas, 5 were inflammation, 1 was occupational interstitial lung disease, and 1 was a pulmonary meningothelial-like nodule. The remaining 4 undiagnosed lesions were confirmed to be adenocarcinomas by further analysis. The diagnostic yield was unchanged by factors including size (GGOs ≥20 mm, GGOs <20 mm), navigation (VBN, ENB), fluoroscopic visibility (visible, invisible), GGO-component (pure GGOs, mixed GGOs), and guide sheath (K-201, K203). There was no presentation of pneumothorax or severe hemorrhage.

Conclusions

The ultrathin cryoprobe is feasible, safe, and has a high diagnostic yield in the diagnosis of pulmonary GGOs. There is vast potential for the ultrathin cryoprobe as a tool for the diagnosis of GGOs, especially for cases suspicious of early-stage lung cancer.

Trial registration

ClinicalTrials.gov. No: NCT03716284. Registered: 20 October, 2018. URL: ClinicalTrials.gov.

Predicting malignancy: subsolid nodules detected on LDCT in a surgical cohort of East Asian patients

Background

Due to widespread use of low-dose computed tomography (LDCT) screening, increasing number of patients are found to have subsolid nodules (SSNs). The management of SSNs is a clinical challenge and primarily depends on CT imaging. We seek to identify risk factors that may help clinicians determine an optimal course of management.

Methods

We retrospectively reviewed the characteristics of 83 SSN lesions, including 48 pure ground-glass nodules and 35 part-solid nodules, collected from 83 patients who underwent surgical resection.

Results

Of the 83 SSNs, 16 (19.28%) were benign and 67 (80.72%) were malignant, including 23 adenocarcinomas in situ (AIS), 16 minimally invasive adenocarcinomas (MIA), and 28 invasive adenocarcinomas (IA). Malignant lesions were found to have significantly larger diameters (P<0.05) with an optimal cut-off point of 9.24 mm. Significant indicators of malignancy include female sex (P<0.05), air bronchograms (P<0.001), spiculation (P<0.05), pleural tail sign (P<0.05), and lobulation (P<0.05). When compared with AIS/MIA combined, IA lesions were found to be larger (P<0.05) with an optimal cut-off of 12 mm, and have a higher percentage of part-solid nodules (P<0.001), pleural tail sign (P<0.001), air bronchograms (P<0.05), and lobulation (P<0.05). Further multivariate analysis found that lesion size and spiculation were independent factors for malignancy while part-solid nodules were associated with IA histology.

Conclusions

East Asian females are at risk of presenting with a malignant lesion even without history of heavy smoking or old age. Nodule features associated with malignancy include larger size, air bronchograms, lobulation, pleural tail sign, spiculation, and solid components. A combination of patient characteristic and LDCT features can be effectively used to guide management of patients with SSNs.

Subsolid pulmonary nodules: Controversy and perspective

Ground glass and part-solid nodules, collectively referred to as subsolid nodules, present a challenge in management, with a high risk of malignancy but, when malignant, demonstrating indolent behavior. Emerging data suggest longer follow-up intervals and shorter duration of follow-up is likely appropriate in these nodules. Additionally, definitive therapy is shifting to less aggressive approaches such as sub-lobar resection. Patients may benefit from individualized approaches, incorporating both patient and imaging features to determine whether treatment is necessary.

Mediastinal lymph node metastases in lung cancer presenting as pure ground-glass nodules: A surgical case report

INTRODUCTION

Generally, lung cancer representing as Ground-glass nodules is associated with an early stage and good prognosis. However, we herein report a rare case of pure ground-glass nodules with mediastinal lymph node metastases.

PRESENTATION OF CASE

A 69-year-old man underwent video assisted thoracic surgery right upper lobectomy with mediastinal lymph node dissection due to multifocal Ground-glass nodules in the right upper lobe of the lung. Histopathologically, six lung adenocarcinomas were present simultaneously. Furthermore, we detected mediastinal lymph nodes metastases that contain micropapillary component. The lung lesion containing micropapillary component was a pure Ground-glass nodule that adjoining pulmonary bulla on CT findings.

DISCUSSION

Generally, lung cancer presenting as pure ground-glass nodules is associated with an early stage and good prognosis. However, the necessity of evaluating the mediastinal lymph nodes in pure ground-glass nodules is controversial. It is reported that lung cancer adjoining the wall of a bulla tends to have a poor prognosis, even when small in size. Therefore, Ground-glass nodules with metastases might have a different pathogenesis than other nodules.

CONCLUSION

Adenocarcinoma appearing as pure Ground-glass nodules is associated with early stage lung cancer and a good prognosis. However, the findings in our patient indicate the importance and necessity of evaluating the mediastinal lymph nodes for metastases intraoperatively.

A Subsolid Nodules Imaging Reporting System (SSN-IRS) for Classifying 3 Subtypes of Pulmonary Adenocarcinoma

OBJECTIVES

To develop an imaging reporting system for the classification of 3 adenocarcinoma subtypes of computed tomography (CT)-detected subsolid pulmonary nodules (SSNs) in clinical patients.

METHODS

Between November 2011 and October 2017, 437 pathologically confirmed SSNs were retrospectively identified. SSNs were randomly divided 2:1 into a training group (291 cases) and a testing group (146 cases). CT-imaging characteristics were analyzed using multinomial univariable and multivariable logistic regression analysis to identify discriminating factors for the 3 adenocarcinoma subtypes (pre-invasive lesions, minimally invasive adenocarcinoma, and invasive adenocarcinoma). These factors were used to develop a classification and regression tree model. Finally, an SSN Imaging Reporting System (SSN-IRS) was constructed based on the optimized classification model. For validation, the classification performance was evaluated in the testing group.

RESULTS

Of the CT-derived characteristics of SSNs, qualitative density (nonsolid or part-solid), core (non-core or core), semantic features (pleural indentation, vacuole sign, vascular invasion), and diameter of solid component (≤6 mm or >6 mm), were the most important factors for the SSN-IRS. The total sensitivity, specificity, and diagnostic accuracy of the SSN-IRS was 89.0% (95% confidence interval [CI], 84.8%-92.4%), 74.6% (95% CI, 70.8%-78.1%), and 79.4% (95% CI, 76.5%-82.0%) in the training group and 84.9% (95% CI, 78.1%-90.3%), 68.5% (95% CI, 62.8%-73.8%), and 74.0% (95% CI, 69.6%-78.0%) in the testing group, respectively.

CONCLUSIONS

The SSN-IRS can classify 3 adenocarcinoma subtypes using CT-based characteristics of subsolid pulmonary nodules. This classification tool can help clinicians to make follow-up recommendations or decisions for surgery in clinical patients with SSNs.

What's New on Quantitative CT Analysis as a Tool to Predict Growth in Persistent Pulmonary Subsolid Nodules? A Literature Review

Pulmonary subsolid nodules (SSNs) are observed not infrequently on thin-section chest computed tomography (CT) images. SSNs persisting after a follow-up period of three to six months have a high likelihood of being pre-malignant or malignant lesions. Malignant SSNs usually represent the histologic spectrum of pulmonary adenocarcinomas, and pulmonary adenocarcinomas presenting as SSNs exhibit quite heterogeneous behavior. In fact, while most lesions show an indolent course and may grow very slowly or remain stable for many years, others may exhibit significant growth in a relatively short time. Therefore, it is not yet clear which persistent SSNs should be surgically removed and for how many years stable SSNs should be monitored. In order to solve these two open issues, the use of quantitative analysis has been proposed to define the "tailored" management of persistent SSNs. The main purpose of this review was to summarize recent results about quantitative CT analysis as a diagnostic tool for predicting the behavior of persistent SSNs. Thus, a literature search was conducted in PubMed/MEDLINE, Scopus, and Web of Science databases to find original articles published from January 2014 to October 2019. The results of the selected studies are presented and compared in a narrative way.

Comparison of Veterans Affairs, Mayo, Brock classification models and radiologist diagnosis for classifying the malignancy of pulmonary nodules in Chinese clinical population

Background

Several classification models based on Western population have been developed to help clinicians to classify the malignancy probability of pulmonary nodules. However, the diagnostic performance of these Western models in Chinese population is unknown. This paper aimed to compare the diagnostic performance of radiologist evaluation of malignancy probability and three classification models (Mayo Clinic, Veterans Affairs, and Brock University) in Chinese clinical pulmonology patients.

Methods

This single-center retrospective study included clinical patients from Tianjin Medical University Cancer Institute and Hospital with new, CT-detected pulmonary nodules in 2013. Patients with a nodule with diameter of 4-25 mm, and histological diagnosis or 2-year follow-up were included. Analysis of area under the receiver operating characteristic curve (AUC), decision curve analysis (DCA) and threshold of decision analysis was used to evaluate the diagnostic performance of radiologist diagnosis and the three classification models, with histological diagnosis or 2-year follow-up as the reference.

Results

In total, 277 patients (286 nodules) were included. Two hundred and seven of 286 nodules (72.4%) in 203 patients were malignant. AUC of the Mayo model (0.77; 95% CI: 0.72-0.82) and Brock model (0.77; 95% CI: 0.72-0.82) were similar to radiologist diagnosis (0.78; 95% CI: 0.73-0.83; P=0.68, P=0.71, respectively). The diagnostic performance of the VA model (AUC: 0.66) was significantly lower than that of radiologist diagnosis (P=0.003). A three-class classifying threshold analysis and DCA showed that the radiologist evaluation had higher discriminatory power for malignancy than the three classification models.

Conclusions

In a cohort of Chinese clinical pulmonology patients, radiologist evaluation of lung nodule malignancy probability demonstrated higher diagnostic performance than Mayo, Brock, and VA classification models. To optimize nodule diagnosis and management, a new model with more radiological characteristics could be valuable.

Quantitative CT Analysis for Predicting the Behavior of Part-Solid Nodules with Solid Components Less than 6 mm: Size, Density and Shape Descriptors

Persistent part-solid nodules (PSNs) with a solid component <6 mm usually represent minimally invasive adenocarcinomas and are significantly less aggressive than PSNs with a solid component ≥6 mm. However, not all PSNs with a small solid component behave in the same way: some nodules exhibit an indolent course, whereas others exhibit more aggressive behavior. Thus, predicting the future behavior of this subtype of PSN remains a complex and fascinating diagnostic challenge. The main purpose of this study was to apply open-source software to investigate which quantitative computed tomography (CT) features may be useful for predicting the behavior of a select group of PSNs. We retrospectively selected 50 patients with a single PSN with a solid component <6 mm and diameter <15 mm. Computerized analysis was performed using ImageJ software for each PSN and various quantitative features were calculated from the baseline CT images. The area, perimeter, mean Feret diameter, linear mass density, circularity and solidity were significantly related to nodule growth (p ≤ 0.031). Therefore, quantitative CT analysis was helpful for predicting the future behavior of a select group of PSNs with a solid component <6 mm and diameter <15 mm.

Long-Term Follow-Up of Ground-Glass Nodules After 5 Years of Stability

INTRODUCTION

Small ground-glass nodules (GGNs) or those with an indeterminate risk on low-dose computed tomography (LDCT) of the chest are recommended at 5-year follow-up, but the rationale for follow-up beyond 5 years is unclear.

METHODS

An observational study was conducted to investigate the natural course of GGNs that had been stable for 5 years by LDCT over 10 years. All eligible GGNs were detected during regular health checkups. Baseline characteristics were compared between GGNs with and without growth. Risk factors for GGN growth were evaluated.

RESULTS

A total of 208 GGNs were detected in 160 participants. GGN growth was identified in 27 (13.0%) GGNs during a follow-up of 136 months on LDCT scans. In approximately 95% of these GGNs, the initial size was less than 6 mm, with 3.2 mm of growth over 8.5 years. Biopsies were performed in 3 of 27 GGNs, revealing adenocarcinoma. In 8 of 27 cases, GGN growth preceded the development of a new solid component. In a multivariate analysis, bubble lucency (p = 0.001), a history of cancer other than lung cancer (p = 0.036), and development of a new solid component (p < 0.001) were significant risk factors for GGN growth.

CONCLUSIONS

GGNs should not be ignored, even when smaller than 6 mm and stable for 5 years, especially when a new solid component appears during follow-up.