Evolving Concepts in the Pathology and Computed Tomography Imaging of Lung Adenocarcinoma and Bronchioloalveolar Carcinoma

Multidimensional biological characteristics of ground glass nodules

The detection rate of ground glass nodules (GGNs) has increased in recent years because of their malignant potential but relatively indolent biological behavior; thus, correct GGN recognition and management has become a research focus. Many scholars have explored the underlying mechanism of the indolent progression of GGNs from several perspectives, such as pathological type, genomic mutational characteristics, and immune microenvironment. GGNs have different major mutated genes at different stages of development; EGFR mutation is the most common mutation in GGNs, and p53 mutation is the most abundant mutation in the invasive stage of GGNs. Pure GGNs have fewer genomic alterations and a simpler genomic profile and exhibit a gradually evolving genomic mutation profile as the pathology progresses. Compared to advanced lung adenocarcinoma, GGN lung adenocarcinoma has a higher immune cell percentage, is under immune surveillance, and has less immune escape. However, as the pathological progression and solid component increase, negative immune regulation and immune escape increase gradually, and a suppressive immune environment is established gradually. Currently, regular computer tomography monitoring and surgery are the main treatment strategies for persistent GGNs. Stereotactic body radiotherapy and radiofrequency ablation are two local therapeutic alternatives, and systemic therapy has been progressively studied for lung cancer with GGNs. In the present review, we discuss the characterization of the multidimensional molecular evolution of GGNs that could facilitate more precise differentiation of such highly heterogeneous lesions, laying a foundation for the development of more effective individualized treatment plans.

Dynamic Analysis of the Impact of Micropapillary Component on Different Recurrence Patterns of Pathological Stage IA3 Lung Adenocarcinoma: A Multicenter, Retrospective Study

BACKGROUND

This study aimed to evaluate the dynamic impact of the micropapillary (MIP) component on local recurrence (LR), distant metastasis (DM), and multiple recurrence (MR) of pathological stage IA3 lung adenocarcinoma.

METHODS

Between July 2012 and July 2020, a total of 351 patients at two medical institutions were enrolled in this study. Cumulative incidence of curves, dynamic risk curves, and time-dependent multivariate analysis was performed to evaluate the effect of the MIP component on patients.

RESULTS

The 5-year cumulative incidence of total recurrence with or without an MIP component was 34.2% and 12.3%, respectively (p = 0.001). In three recurrence patterns, our findings revealed that the 5-year cumulative incidence of LR (p = 0.048) and DM (p = 0.005) was higher in the 'MIP-present' group than in the 'MIP-absent' group. In the dynamic recurrence curve, the risk of the three recurrence patterns was different and varied over time between the two groups, especially in DM. Moreover, the dynamic cumulative event curve showed that after 1, 2, and 3 years of survival, the cumulative incidence of DM in the group with MIP continued to be higher than that in the group without MIP (all p < 0.05). Time-dependent Cox regression analysis indicated that the MIP component continued to be an independent risk factor for the cumulative incidence of DM in patients with 3-year survival.

CONCLUSIONS

Of the three recurrence patterns, the MIP component mainly aggravated the risk of DM in patients with pathological stage IA3 lung adenocarcinoma, which persisted for 3 years.

Establishing a prognostic model based on immune-related genes and identification of BIRC5 as a potential biomarker for lung adenocarcinoma patients

BACKGROUND

Lung adenocarcinoma (LUAD) is an extraordinarily malignant tumor, with rapidly increasing morbidity and poor prognosis. Immunotherapy has emerged as a hopeful therapeutic modality for lung adenocarcinoma. Furthermore, a prognostic model (based on immune genes) can fulfill the purpose of early diagnosis and accurate prognostic prediction.

METHODS

Immune-related mRNAs (IRmRNAs) were utilized to construct a prognostic model that sorted patients into high- and low-risk groups. Then, the prediction efficacy of our model was evaluated using a nomogram. The differences in overall survival (OS), the tumor mutation landscape, and the tumor microenvironment were further explored between different risk groups. In addition, the immune genes comprising the prognostic model were subjected to single-cell RNA sequencing to investigate the expression of these immune genes in different cells. Finally, the functions of BIRC5 were validated through in vitro experiments.

RESULTS

Patients in different risk groups exhibited sharply significant variations in OS, pathway activity, immune cell infiltration, mutation patterns, and immune response. Single-cell RNA sequencing revealed that the expression level of BIRC5 was significantly high in T cells. Cell experiments further revealed that BIRC5 knockdown markedly reduced LUAD cell proliferation.

CONCLUSION

This model can function as an instrumental variable in the prognostic, molecular, and therapeutic prediction of LUAD, shedding new light on the optimal clinical practice guidelines for LUAD patients.

A novel signature predicts prognosis and immunotherapy in lung adenocarcinoma based on cancer-associated fibroblasts

Background

Extensive research has established the significant correlations between cancer-associated fibroblasts (CAFs) and various stages of cancer development, including initiation, angiogenesis, progression, and resistance to therapy. In this study, we aimed to investigate the characteristics of CAFs in lung adenocarcinoma (LUAD) and develop a risk signature to predict the prognosis of patients with LUAD.

Methods

We obtained single-cell RNA sequencing (scRNA-seq) and bulk RNA-seq data from the public database. The Seurat R package was used to process the scRNA-seq data and identify CAF clusters based on several biomarkers. CAF-related prognostic genes were further identified using univariate Cox regression analysis. To reduce the number of genes, Lasso regression was performed, and a risk signature was established. A novel nomogram that incorporated the risk signature and clinicopathological features was developed to predict the clinical applicability of the model. Additionally, we conducted immune landscape and immunotherapy responsiveness analyses. Finally, we performed in vitro experiments to verify the functions of EXO1 in LUAD.

Results

We identified 5 CAF clusters in LUAD using scRNA-seq data, of which 3 clusters were significantly associated with prognosis in LUAD. A total of 492 genes were found to be significantly linked to CAF clusters from 1731 DEGs and were used to construct a risk signature. Moreover, our immune landscape exploration revealed that the risk signature was significantly related to immune scores, and its ability to predict responsiveness to immunotherapy was confirmed. Furthermore, a novel nomogram incorporating the risk signature and clinicopathological features showed excellent clinical applicability. Finally, we verified the functions of EXP1 in LUAD through in vitro experiments.

Conclusions

The risk signature has proven to be an excellent predictor of LUAD prognosis, stratifying patients more appropriately and precisely predicting immunotherapy responsiveness. The comprehensive characterization of LUAD based on the CAF signature can predict the response of LUAD to immunotherapy, thus offering fresh perspectives into the management of LUAD patients. Our study ultimately confirms the role of EXP1 in facilitating the invasion and growth of tumor cells in LUAD. Nevertheless, further validation can be achieved by conducting in vivo experiments.

Radiological precursor lesions of lung squamous cell carcinoma: Early progression patterns and divergent volume doubling time between hilar and peripheral zones

OBJECTIVES

This study investigated the early progression patterns of lung squamous cell carcinoma (SqCC) on computed tomography (CT) images.

MATERIALS AND METHODS

In total, 65 patients with SqCC who underwent surgical resection and two CT scans separated by an interval of at least 6 months were enrolled. We categorized the findings of the initial and at-diagnosis CT images into five patterns as previously reported. The volume doubling time (VDT) was calculated for measurable lesions.

RESULTS

A single nodule pattern on CT images at-diagnosis was most common in 56 (86.2 %) patients, in line with practical clinical findings. However, the patterns were diverse in the initial images, with 28 (43.1 %) patients displaying atypical findings, including multiple nodules (3.1 %), endobronchial lesions (20.0 %), subsolid nodules (10.8 %), and cyst wall thickening (9.2 %). All endobronchial lesions were located in the central/middle zone of the lung field, whereas lesions presented as multiple nodules, subsolid nodules, and cyst wall thickening were predominantly observed in the peripheral zone. The differences in the developed zones were reflected in the median VDT, and the tumors with an initial endobronchial pattern had a significantly shorter VDT than those with a subsolid nodule pattern (median: 140 days vs 276 days, p < 0.001).

CONCLUSIONS

Lung SqCC initiated with various CT image patterns, although most tumors ultimately developed a single nodule pattern by diagnosis. The initial CT image patterns differed between the hilar and peripheral zones, suggesting a difference in the progression scheme, which was also supported by differences in VDT.

The natural growth history of persistent pulmonary subsolid nodules: Radiology, genetics, and clinical management

The high detection rate of pulmonary subsolid nodules (SSN) is an increasingly crucial clinical issue due to the increased number of screening tests and the growing popularity of low-dose computed tomography (LDCT). The persistence of SSN strongly suggests the possibility of malignancy. Guidelines have been published over the past few years and guide the optimal management of SSNs, but many remain controversial and confusing for clinicians. Therefore, in-depth research on the natural growth history of persistent pulmonary SSN can help provide evidence-based medical recommendations for nodule management. In this review, we briefly describe the differential diagnosis, growth patterns and rates, genetic characteristics, and factors that influence the growth of persistent SSN. With the advancement of radiomics and artificial intelligence (AI) technology, individualized evaluation of SSN becomes possible. These technologies together with liquid biopsy, will promote the transformation of current diagnosis and follow-up strategies and provide significant progress in the precise management of subsolid nodules in the early stage of lung cancer.

Lepidic growth component as a favorable prognostic factor in non-small cell lung cancer of ≤3 cm

BACKGROUND

Many non-small cell lung cancer (NSCLC) tumors present complex histology with various components. The effects of the lepidic growth component (LGC) on the prognosis of NSCLC have not been investigated. Here, we investigated whether an LGC is a relevant prognostic factor for NSCLC.

METHODS

This study retrospectively investigated the clinicopathologic characteristics of 379 patients with NSCLC ≤3 cm who underwent complete surgical resection between 2004 and 2016 at the University of Yamanashi Hospital. The histologic subtypes were classified into NSCLC with or without an LGC. We evaluated the effect of an LGC on the clinicopathologic features and 5-year overall survival of patients with NSCLC.

RESULTS

On final pathology, 214 (56%) of 379 patients had an LGC, and 165 (44%) did not. Sex, smoking history, ground-glass opacity component, pathologic invasive size, lymph node metastasis, pleural invasion, vessel invasion, pathologic stage, and histologic type were significantly different between the groups. Multivariate analysis of 5-year overall survival, identified age (hazard ratio [HR], 1.07; 95% confidence interval [CI], 1.035-1.105; p < 0.001), pathologic invasive size (HR, 1.548; 95% CI, 1.088-2.202; p = 0.015) and LGC (HR, 2.11; 95% CI, 1.099-4.051; p = 0.025) as independent prognostic factors. When the pathologic invasive size was matched, the 5-year overall survival of the LGC and non-LGC groups was 93% and 77%, respectively (p = 0.006).

CONCLUSIONS

LGC is a significantly favorable prognostic factor for NSCLC with a pathologic invasive size of ≤3 cm.

Solitary Pulmonary Capillary Hemangioma: CT and PET-CT Features with Clinicopathologic Correlation

The aim of this study was to evaluate the CT and PET-CT features of solitary pulmonary capillary hemangioma (SPCH) with clinicopathologic correlations. This retrospective study included 17 patients with histologically proven SPCH from four tertiary institutions. The clinical, pathological and imaging findings of SPCH were reviewed. The CT features assessed included lesion location, size, density, contour, margin, enhancement, presence of air bronchogram, perivascular lucency and pleural retraction, and 18F-fluorodeoxyglucose uptake on PET-CT. Changes in the size during the follow-up period were also evaluated. Imaging features were correlated with the clinicopathologic findings. The mean age of the patients was 47 years (range 30–60 years). All SPCHs were incidentally detected during screening CT examinations (n = 13, 76%) or during cancer work-up (n = 4, 24%). Most SPCHs appeared as part-solid nodules (n = 15, 88%), the remaining appeared as a pure ground-glass nodule or a pure solid nodule, respectively. Most had smooth contours (n = 16, 94%), while one had a lobulated contour. Nine SPCHs (53%) showed ill-defined margins. Air bronchogram was present in ten (59%) SPCHs, and perivascular lucency in two (12%). All SPCHs exhibited hypoattenuation on contrast-enhanced CT and hypometabolism on PET-CT. During the follow-up period (mean 14.8 ± 17.7 months), the lesions showed no change in size or density in ten SPCHs (59%), decreased or fluctuation in size and density in three (18%). SPCH is often incidentally detected in young and middle-aged adults, commonly as an ill-defined part-solid nodule that may accompany air bronchogram, perivascular lucency, and fluctuation in size or density on CT and hypometabolism on PET-CT.

Comprehensive analysis reveals the potential value of inflammatory response genes in the prognosis, immunity, and drug sensitivity of lung adenocarcinoma

Background

Although the relationship between inflammatory response and tumor has been gradually recognized, the potential implications of of inflammatory response genes in lung adenocarcinoma (LUAD) remains poorly investigated.

Methods

RNA sequencing and clinical data were obtained from multiple independent datasets (GSE29013, GSE30219, GSE31210, GSE37745, GSE42127, GSE50081, GSE68465, GSE72094, TCGA and GTEx). Unsupervised clustering analysis was used to identify different tumor subtypes, and LASSO and Cox regression analysis were applied to construct a novel scoring tool. We employed multiple algorithms (ssGSEA, CIBERSORT, MCP counter, and ESTIMATE) to better characterize the LUAD tumor microenvironment (TME) and immune landscapes. GSVA and Metascape analysis were performed to investigate the biological processes and pathway activity. Furthermore, ‘pRRophetic’ R package was used to evaluate the half inhibitory concentration (IC50) of each sample to infer drug sensitivity.

Results

We identified three distinct tumor subtypes, which were related to different clinical outcomes, biological pathways, and immune characteristics. A scoring tool called inflammatory response gene score (IRGS) was established and well validated in multiple independent cohorts, which could well divide patients into two subgroups with significantly different prognosis. High IRGS patients, characterized by increased genomic variants and mutation burden, presented a worse prognosis, and might show a more favorable response to immunotherapy and chemotherapy. Additionally, based on the cross-talk between TNM stage, IRGS and patients clinical outcomes, we redefined the LUAD stage, which was called ‘IRGS-Stage’. The novel staging system could distinguish patients with different prognosis, with better predictive ability than the conventional TNM staging.

Conclusions

Inflammatory response genes present important potential value in the prognosis, immunity and drug sensitivity of LUAD. The proposed IRGS and IRGS-Stage may be promising biomarkers for estimating clinical outcomes in LUAD patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01340-7.

Integrated Analysis Reveals the Potential Significance of HDAC Family Genes in Lung Adenocarcinoma

Histone deacetylases comprise a family of 18 genes, and classical HDACs are a promising class of novel anticancer drug targets. However, to date, no systematic study has been comprehensive to reveal the potential significance of these 18 genes in lung adenocarcinoma (LUAD). Here, we used a systematic bioinformatics approach to comprehensively describe the biological characteristics of the HDACs in LUAD. Unsupervised consensus clustering was performed to identify LUAD molecular subtypes. The ssGSEA, CIBERSORT, MCP counter, and ESTIMATE algorithms were used to depict the tumor microenvironment (TME) landscape. The Cox proportional hazards model and LASSO regression analyses were used to construct the HDAC scoring system for evaluating the prognosis of individual tumors. In this study, three distinct HDAC-mediated molecular subtypes were determined, which were also related to different clinical outcomes and biological pathways. HDACsCluster-C subtype had lowest PD-L1/PD-1/CTLA4 expression and immune score. The constructed HDAC scoring system (HDACsScore) could be used as an independent predictor to assess patient prognosis and effectively identify patients with different prognosis. High- and low-HDACsScore groups presented distinct genetic features, immune infiltration, and biological processes. The high-HDACsScore group was more likely to benefit from immunotherapy, as well as from the application of common chemotherapeutic agents (cyclopamine, docetaxel, doxorubicin, gemcitabine, paclitaxel, and pyrimethamine). Overall, HDAC family genes play important roles in LUAD, and the three LUAD subtypes and the HDAC scoring system identified in this study would help enhance our perception of LUAD prognostic differences and provide important insights into the efficacy of immunotherapy and chemotherapy.

Unusual presentation of lepidic adenocarcinoma in a healthy female

Background

Lepidic adenocarcinoma represents a histologic pattern of non-small cell lung cancer that characteristically arises in the lung periphery with tracking alongside pre-existing alveolar walls. Noninvasive and invasive variants of lepidic adenocarcinoma are dependent on parenchymal destruction, vascular, or pleural invasion. The lepidic-predominant lung malignancies are collectively recognized as slow growing with rare metastasis and excellent prognosis. The World Health Organization classification of lung malignancies depends on molecular and histopathological findings. CT findings most commonly include ground-glass characteristics, commonly mistaken for inflammatory or infectious etiology. These tumors are generally surgically resectable and associated with better survival given infrequent nodal and extrathoracic involvement. Rarely these tumors present with diffuse pneumonic-type involvement associated with worse outcomes despite lack of nodal and distant metastases.

Case presentation

A 63-year-old Caucasian athletic immunocompetent female presented with 2 months of progressive shortness of breath, fatigue, loss of appetite and 15 pound weight loss. History was only notable for well controlled essential hypertension and hypothyroidism. Contrast computed tomography angiogram and positron emission tomography revealed diffuse hypermetabolic interstitial and airspace abnormalities of the lungs without lymphadenopathy (or distant involvement) in addition to right hydropneumothorax and left pleural effusion. Baseline laboratory testing was unremarkable, and extensive bacterial and fungal testing returned negative. Bronchoscopy and video-assisted thoracoscopic surgery was subsequently performed with pleural fluid cytology, lung and pleural biopsies returning positive for lepidic adenocarcinoma with 2% programmed death ligand 1 expression and genomic testing positive for PTEN gene deletion. Prior to treatment, the patient perished on day 15 of admission.

Conclusion

We present a rare case of lepidic predominant adenocarcinoma with extensive bilateral aerogenous spread in the context of no lymphovascular invasion in a healthy, low risk patient. This case presentation may add to the body of knowledge regarding the different behavior patterns of lepidic predominant adenocarcinomas.

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.

Pulmonary Nodule and Mass: Superiority of MRI of Diffusion-Weighted Imaging and T2-Weighted Imaging to FDG-PET/CT

Simple Summary

Although diffusion-weighted imaging (DWI) can be valuable for differential diagnosis of lung cancer from benign pulmonary nodules and masses (PNMs), the diagnostic capability may not be perfect. This study’s purpose was to compare the diagnostic efficacy of 18-fluoro-2-deoxy-glucose positron emission tomography–computed tomography (FDG-PET/CT) and magnetic resonance imaging (MRI) of DWI and T2-weighted imaging (T2WI) in PNMs. There were 278 lung cancers and 50 benign PNMs that were examined by FDG-PET/CT and MRI. The sensitivity of the maximum standardized uptake value (SUVmax) was significantly lower than that of the apparent diffusion coefficient (ADC) and the T2 contrast ratio (T2 CR). The accuracy of SUVmax was significantly lower than that of ADC and that of T2 CR. The sensitivity and accuracy of MRI were significantly higher than those of FDG-PET/CT. MRI can replace FDG-PET/CT for differential diagnosis of PNMs.

Abstract

The purpose of this retrospective study was to compare the diagnostic efficacy of FDG-PET/CT and MRI in discriminating malignant from benign pulmonary nodules and masses (PNMs). There were 278 lung cancers and 50 benign PNMs that were examined by FDG-PET/CT and MRI. The T2 contrast ratio (T2 CR) was designated as the ratio of T2 signal intensity of PNM divided by T2 signal intensity of the rhomboid muscle. The optimal cut-off values (OCVs) for differential diagnosis were 3.605 for maximum standardized uptake value (SUVmax), 1.459 × 10⁻³ mm²/s for apparent diffusion coefficient (ADC), and 2.46 for T2 CR. Areas under the receiver operating characteristics curves were 67.5% for SUVmax, 74.3% for ADC, and 72.4% for T2 CR, respectively. The sensitivity (0.658) of SUVmax was significantly lower than that (0.838) of ADC (p < 0.001) and that (0.871) of T2 CR (p < 0.001). The specificity (0.620) of SUVmax was that the same as (0.640) ADC and (0.640) of T2 CR. The accuracy (0.652) of SUVmax was significantly lower than that (0.808) of ADC (p < 0.001) and that (0.835) of T2 CR (p < 0.001). The sensitivity and accuracy of DWI and T2WI in MRI were significantly higher than those of FDG-PET/CT. Ultimately, MRI can replace FDG PET/CT for differential diagnosis of PNMs saving healthcare systems money while not sacrificing the quality of care.

Validation of the Novel International Association for the Study of Lung Cancer Grading System for Invasive Pulmonary Adenocarcinoma and Association With Common Driver Mutations

INTRODUCTION

We aimed to validate the use of the novel grading system proposed by the International Association for the Study of Lung Cancer pathology committee for prognosis stratification of invasive pulmonary adenocarcinomas (ADCs) in Chinese patients. Correlations between the grading system, common driver mutations, and adjuvant chemotherapy (ACT) were also investigated.

METHODS

From 2008 to 2016, the histologic patterns of a large cohort of 950 patients with invasive ADCs (stage I-III) were retrospectively analyzed and classified according to the proposed grading system. Subsequently, tumor grading was correlated with genetic data, ACT, and patient outcome.

RESULTS

Compared with conventional predominant pattern-based groups, the novel grading system carried improved survival discrimination (area under the curve = 0.768 for recurrence-free survival and 0.775 for overall survival). The area under the curve was not further improved when incorporated lymphovascular invasion status. EGFR mutations (p < 0.001) were correlated with moderate grade, whereas KRAS mutations (p = 0.041) and ALK fusions (p = 0.021) were significantly more prevalent in poor grade. The reclassification of the grading system based on EGFR mutation status revealed excellent survival discrimination (p < 0.001). In particular, patients on stage Ib to III with novel high-grade ADCs had an improved prognosis with ACT.

CONCLUSIONS

The novel International Association for the Study of Lung Cancer grading system is a practical and efficient discriminator for patient prognosis and should be part of an integrated pathologic-genetic subtyping to improve survival prediction. In addition, it may support patient stratification for aggressive adjuvant chemotherapy.

Clinical and surgical approaches for malignant pulmonary lesions after a previous extrapulmonary malignancy

BACKGROUND

In our study, since the operative histopathological distinction of new malignant pulmonary lesions as either a primary lung cancer or a pulmonary metastasis is difficult, we aimed to identify the clinical variables which might allow distinction between a new lung cancer and a pulmonary metastasis, and the appropriate surgical management.

METHODS

We divided 55 cases into two groups: patients with new lung cancer (NLC, n = 32) and patients with pulmonary metastases (PM, n = 23). Based on the primary organ, the previous malignancy was classified into four categories: head and neck, colorectal, genitourinary, and breast cancer. The parameters included in the study were age, sex, smoking history, a family history of cancer, disease-free interval, primary organ, treatments for previous malignancies, size, and SUV max of the lung lesion on 18F-fluorodeoxyglucose positron emission tomography scan and high-resolution computed tomography findings of the lung lesion.

RESULTS

A predisposition for larger lesions was found in the NLC group. In addition, in the NLC group, disease-free interval was noted to be longer, patients were significantly older and SUV-max values of solitary pulmonary lesions were significantly higher than in the PM group. Pulmonary lesions in patients with prior head and neck cancers were more likely to develop NLC. No significant difference in statistical analysis was observed between the groups in terms of sex, smoking, a family history of cancer, a history of adjuvant therapy, radiological pulmonary lesions signs, and localization.

CONCLUSION

PL monitoring on CT surveillance is essential, particularly in patients with previous head and neck cancers, who appear to have a higher risk for NLC. If pathological MLN accompanies PL in a patient with previous extrapulmonary malignancy, cervical mediastinoscopy may help acquire a possible PL diagnosis besides mediastinal staging. Intraoperative frozen section may have difficulty in distinguishing between PM and NLC when the lesion is of the same histological type as the previous malignancy. When precise distinction cannot be achieved by frozen section, we speculate that DFI, age, and radiological findings of the PL may help thoracic surgeons take initiative peroperatively while designating the subsequent surgical intervention. Lastly, pulmonary segmentectomy is also better be considered along with lobectomy in NLC cases.

Impact of the micropapillary component on the timing of recurrence in patients with resected lung adenocarcinoma

OBJECTIVES

A micropapillary (MIP) component is reported to be associated with a poor prognosis in patients with completely resected lung adenocarcinoma. The purpose of this study was to investigate the impact of an MIP component on the timing of postoperative recurrence using hazard curves.

METHODS

A total of 1289 patients with lung adenocarcinoma who underwent complete pulmonary resection from 2008 to 2015 were studied. Hazard curves representing the changes in hazard over time were evaluated.

RESULTS

The hazard curve displayed an initial wide, high peak within 1 year after surgery in patients with an MIP component, whereas some gentle peaks around the second year were noted in patients without an MIP component. The presence of an MIP component was associated with a worse recurrence-free survival and an early recurrence in stage I patients but not in advanced-stage patients. In multivariable Cox regression, the presence of an MIP component and lymph node metastasis, pleural invasion and gender were associated with a poor prognosis.

CONCLUSIONS

Patients with an MIP component retained a high risk of early recurrence after surgery, and the risk for recurrence persisted over the long term. Even after complete resection in stage I lung adenocarcinoma patients, an MIP component remains correlated with a poor prognosis.

The Prognostic Value of Non-Predominant Micropapillary Pattern in a Large Cohort of Resected Invasive Lung Adenocarcinoma Measuring ≤3 cm

The aim of this study was to analyze the influence of non-predominant micropapillary pattern in small sized invasive lung adenocarcinoma. A total of 986 lung adenocarcinoma patients with tumor size ≤3 cm were identified and classified according to the IALSC/ATS/ERS classification. Emphasis was placed on the impact of non-predominant micropapillary pattern on disease-free survival (DFS) and overall survival (OS). The relationship between lung adenocarcinoma subtype and lymph node involvement, EGFR mutation and KRAS mutation was also evaluated. A nomogram was developed to predict the probability of 3- and 5-year OS for these patients. The concordance index and calibration plot were used to validate this model. Among all 986 patients, the percentages of lymph node involvement were: 58.1, 50.0, 33.5, 21.4, 21.1, 10.9, 0, and 0% for micropapillary predominant, solid predominant, acinar predominant, papillary predominant, invasive mucinous adenocarcinoma (IMA), lepidic predominant, minimally invasive adenocarcinoma (MIA), adenocarcinoma in situ (AIS), respectively. The frequency of EGFR mutation in the cases of lepidic predominant, acinar predominant, MIA, micropapillary predominant, papillary predominant, solid predominant, IMA, and AIS were 51.1, 45.2, 44.4, 36.8, 29.3, 26.8, 8.3, and 0%, respectively. A non-predominant micropapillary pattern was observed in 344 (38.4%) invasive adenocarcinoma (IAC), and its presence predicted a poorer DFS (median: 56.0 months vs. 66.0 months, P <0.001) and OS (median: 61.0 months vs. 70.0 months, P <0.001). After propensity score matching, non-predominant micropapillary pattern retained its unfavorable effect on DFS (P = 0.007) and OS (P = 0.001). Multivariate analysis showed that non-predominant micropapillary pattern was identified as an independent prognostic factor for DFS (P = 0.003) and OS (P <0.001) in IAC. The nomogram showed good calibration and reliable discrimination ability (C-index = 0.775) to evaluated the 3- and 5-year OS. This retrospective analysis of patients with small sized IAC suggests the value of non-predominant micropapillary pattern to predict poor prognosis. A reliable nomogram model was constructed to provide personalized survival predictions.

A case report of pneumonic-type adenocarcinoma diagnosed by transbronchial cryobiopsy after the patient's death

RATIONALE

Due to its nonspecific manifestations, pneumonic-type adenocarcinoma can be easily misdiagnosed as pneumonia, tuberculosis, or other diseases, especially in developing countries where many patients in the early stage refuse invasive examinations. Early recognition of pneumonic-type adenocarcinoma is essential.

PATIENT CONCERNS

We report a case of pneumonia lung adenocarcinoma diagnosed by frozen lung biopsy after death.

DIAGNOSES

A 75-year-old male patient was admitted to the hospital on April 24, complaining of 5 months of recurrent coughing, expectoration, and panting, and his symptoms had been worsening over the past month.

INTERVENTIONS

After obtaining informed consent from the patient's family, transbronchial cryobiopsy was performed at the bedside.

OUTCOMES

After a positive rescue, the patient died. Pathological examination indicated adenocarcinoma.

LESSONS

At present, surgery is still the first choice for the treatment of pneumonic lung cancer, and early diagnosis can remove the tumor as much as possible. Transbronchial cryobiopsy can be used for the collection of pathological samples, especially for the early diagnosis of pneumonic lung cancer.

The utility of three-dimensional computed tomography for prediction of tumor invasiveness in clinical stage IA lung adenocarcinoma

Background

It is critical to have an accurate measurement of solid tumor size in order to predict the invasiveness of small lung adenocarcinomas. Some lesions cannot be measured accurately via High-resolution computed tomography (HRCT) due to their irregular shape and unclear borders. For this reason, we evaluated the relative efficacy of three-dimensional (3D) CT for predicting invasive adenocarcinoma.

Methods

We evaluated 195 patients with clinical stage IA adenocarcinomas, including 109 with lesions documented as invasive that were surgically resected at our institute during 2017. All lesions were categorized as either (I) lesions that were difficult to evaluate (i.e., hazy lesions; HL) or (II) more typical lesions (TL). The relationships between solid tumor size as determined by HRCT, solid tumor volume as determined by 3D CT and pathologic diagnosis were evaluated.

Results

Fifty-seven patients (29%) were diagnosed with HL. We set the cut-off value for the solid volume at 225 mm³ as predictive for invasive adenocarcinoma. When evaluating all 195 patients as a group, the accuracy, sensitivity, and specificity based on the solid tumor volume were similar to those based on the solid tumor size. When we limit our analysis to the HL group, the specificity based on solid tumor volume (65.5%) was higher than that based on solid tumor size (44.8%) with a difference that approached statistical significance (P=0.070).

Conclusions

3D CT was equivalent to HRCT for predicting invasive adenocarcinoma and may be particularly useful for diagnosing lesions that are difficult to evaluate on HRCT.

Adenocarcinoma of the lung: from BAC to the future

Adenocarcinoma in situ, minimally invasive adenocarcinoma, lepidic predominant adenocarcinoma and invasive mucinous adenocarcinoma are relatively new classification entities which replace the now retired term, bronchoalveolar carcinoma (BAC). The radiographic appearance of these lesions ranges from pure, ground glass nodules to large, solid masses. A thorough understanding of the new classification is essential to radiologists who work with MDT colleagues to provide accurate staging and treatment. A 2-year review was performed of all surgically resected cases of adenocarcinoma in situ, minimally invasive adenocarcinoma and lepidic predominant adenocarcinoma in our institution. Cases are broken down by age, gender, tumour type and tumour location. A pictorial review is presented to illustrate the radiologic and pathologic features of each entity.

Typical presentation of pulmonary lepidic adenocarcinoma: a rare case report

Bronchioloalveolar carcinoma (BAC) is a rare subtype of adenocarcinoma of lung with distinct features and distinctive characteristics. It accounts approximately for 4% of lung cancers. In the following study we report a rare observation of a 50 years old female with a clinical, radiological and histological presentation, which is typical of an invasive mucinous lepidic adenocarcinoma formerly named BAC.

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

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

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

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

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

Pulmonary adenocarcinoma appearing as ground-glass opacity nodules identified using non-enhanced and contrast-enhanced CT texture analysis: A retrospective analysis

The present study aimed to investigate the ability of CT-based texture analysis to differentiate invasive adenocarcinoma (IA) from pre-invasive lesions (PIL) or minimally IA (MIA) appearing as ground-glass opacity (GGO) nodules, and to further compare the performance of non-enhanced CT (NECT) images with that of contrast-enhanced CT (CECT) images. A total of 77 patients with GGO nodules and surgically confirmed pulmonary adenocarcinoma were included in the present retrospective study. Each GGO nodule was manually segmented and its texture features were extracted from NECT and CECT images using in-house developed software coded in MATLAB (MathWorks). The independent-samples t-test was used to select the texture features with statistically significant differences between IA and MIA/PIL. Multivariate logistic regression and receiver operating characteristics (ROC) curve analyses were performed to identify predictive features. Of the 77 GGO nodules, 12 were atypical adenomatous hyperplasia or adenocarcinoma in situ (15.6%), 36 were MIA (46.8%) and 29 were IA (37.7%). IA and MIA/PIL exhibited significant differences in most histogram features and gray-level co-occurrence matrix features (P<0.05). Multivariate logistic regression and ROC curve analyses revealed that smaller energy and higher entropy were significant differentiators of IA from MIA and PIL, irrespective of whether NECT images [area under the curve (AUC): 0.839, 0.859] or CECT images (AUC: 0.818, 0.820) are used. Texture analysis of CT images, regardless of whether NECT or CECT is used, has the potential to distinguish IA from PIL or MIA, particularly the parameters of energy and entropy. Furthermore, NECT images were simpler to obtain and no contrast agent was required; thus, analysis with NECT may be a preferred choice.

Long-term survival outcome after lobectomy in patients with clinical T1 N0 lung cancer

OBJECTIVE

The aim of this study was to assess long-term outcomes after lobectomy in patients with clinical T1 N0 lung cancer based on thin-section computed tomography.

METHODS

We collected the data of patients with pathological adenocarcinoma who had undergone lobectomy. The patients were categorized into 4 groups according to a consolidation tumor ratio and tumor size. Groups A and B included tumors with consolidation tumor ratio ≤0.5 and size ≤3 cm. Group A consisted of tumors ≤2 cm. Group B consisted of the remaining tumors. Groups C and D consisted of tumors with consolidation tumor ratio >0.5. Group C consisted of those with tumors ≤2 cm and Group D consisted of tumors of size 2 to 3 cm. The 10-year overall survival and recurrence-free survival rates were examined.

RESULTS

Among the 543 patients, the 10-year overall survival was 80.4% and the 10-year recurrence-free survival rate was 77.1%. The 10-year overall survival for group A was 94.0%, 92.7% for group B, 84.1% for group C, and 68.8% for group D, and the 10-year recurrence-free survival rate for each group was 94.0%, 89.0%, 79.7%, and 66.1%, respectively. Group A + B showed better overall survival than group C + D (hazard ratio, 2.78; 95% confidence interval, 1.45-5.06) and better 10-year recurrence-free survival (hazard ratio, 2.74; 95% confidence interval, 1.55-4.88). No patient in group A had recurrence.

CONCLUSIONS

Those patients with total tumor size ≤3 cm and consolidation tumor ratio ≤0.5 showed excellent prognosis and might be suitable candidates for sublobar resection. If noninferior survival of segmentectomy compared with lobectomy is confirmed in an ongoing Japan Clinical Oncology Group trial, segmentectomy will be included in the standard of care.

Interobserver size measurement variability in part-solid lung adenocarcinoma using pre-operative computed tomography

Background

In the current lung cancer tumor-node-metastasis classification, solid tumor size is used for tumor diameter measurement as the dense component. However, measuring solid tumor size is sometimes difficult and inter-observer variability may increase, particularly in part-solid nodules with ground-glass opacity (GGO). This study aimed to investigate inter-observer size measurement variability in lung adenocarcinoma.

Methods

Of 47 patients with part-solid lung adenocarcinoma who had undergone surgery at our department from January to December 2016, five surgeons and one radiologist undertook unidimensional solid and total size tumor measurements using pre-operative axial computed tomography images, and we assessed inter-observer size measurement variability. Variability was then subclassified into five groups, according to computer tomography-identified tumor morphological characteristics, namely: (I) minimally invasive; (II) peribronchovascular; (III) spiculation/atelectasis; (IV) adjacent to cystic lesion, and; (V) diffuse consolidation and GGO.

Results

The mean inter-observer variability was 9.7 mm (solid size) and 7.7 mm (total size). Analysis of the maximum and minimum measurement size values for each patient undertaken showed that the most experienced surgeon and the radiologist measured the minimum size more frequently. To correct for differences in mean tumor diameter in each group, a comparison was made using a coefficient of variation (CV) calculated as the ratio of the standard deviation to the mean. Group I characteristics showed the largest coefficient value for variation in solid size measurement.

Conclusions

Inter-observer measurement variability for solid size was larger than for total size in lung adenocarcinoma. Large variability in group I indicated the difficulty of size measurement for low-grade malignant potential nodules such as adenocarcinoma in situ, minimally invasive adenocarcinoma, and early-stage invasive adenocarcinoma. The possibility of unavoidable size measurement variability should be recognized when deciding on surgical procedures for these diseases.

Can texture features improve the differentiation of infiltrative lung adenocarcinoma appearing as ground glass nodules in contrast-enhanced CT?

OBJECTIVES

To investigate the validity and efficacy of comparing texture features from contrast-enhanced images with non-enhanced images in identifying infiltrative lung adenocarcinoma represented as ground glass nodules (GGN).

MATERIALS AND METHODS

A retrospective cohort study was conducted with patients presenting with lung adenocarcinoma and treated at a single centre between January 2015 to December 2017. All patients underwent standard and contrast-enhanced thoracic CT scans with 0.5 mm collimation and 1 mm slice reconstruction thickness before surgery. A total of 34 lung adenocarcinoma patients (representing 34 lesions) were analysed; including 21 instances of invasive adenocarcinoma (IAC) lesions, 4 instances of adenocarcinoma in situ (AIS) lesions, and 9 minimally invasive adenocarcinoma (MIA) lesions. After radiologists manually segmented the lesions, texture features were quantitatively extracted using Artificial Intelligence Kit (AK) software. Then, multivariate logistic regression analysis based on standard and contrast-enhanced CT texture features was employed to analyse the invasiveness of lung adenocarcinoma lesions appearing as GGNs. A receiver operating characteristic (ROC) curve analysis was used to evaluate the performance of those models.

RESULTS

A total of 21 quantitative texture features were extracted using the AK software. After dimensionality reduction, 5 and 3 features extracted from thin-section unenhanced and contrast-enhanced CT, respectively, were used to establish the model. The area under the ROC curve (AUC) values for unenhanced CT and enhanced CT features were 0.890 and 0.868, respectively. There was no significant difference (P = 0.190) in the AUC between models based on non-enhanced and contrast-enhanced CT texture features.

CONCLUSION

Compared with unenhanced CT, texture features extracted from contrast-enhanced CT provided no benefit in improving the differential diagnosis of infiltrative lung adenocarcinoma from non-infiltrative malignancies appearing as GGNs.

LUADpp: an effective prediction model on prognosis of lung adenocarcinomas based on somatic mutational features

Background

Lung adenocarcinoma is the most common type of lung cancers. Whole-genome sequencing studies disclosed the genomic landscape of lung adenocarcinomas. however, it remains unclear if the genetic alternations could guide prognosis prediction. Effective genetic markers and their based prediction models are also at a lack for prognosis evaluation.

Methods

We obtained the somatic mutation data and clinical data for 371 lung adenocarcinoma cases from The Cancer Genome Atlas. The cases were classified into two prognostic groups (3-year survival), and a comparison was performed between the groups for the somatic mutation frequencies of genes, followed by development of computational models to discrete the different prognosis.

Results

Genes were found with higher mutation rates in good (≥ 3-year survival) than in poor (< 3-year survival) prognosis group of lung adenocarcinoma patients. Genes participating in cell-cell adhesion and motility were significantly enriched in the top gene list with mutation rate difference between the good and poor prognosis group. Support Vector Machine models with the gene somatic mutation features could well predict prognosis, and the performance improved as feature size increased. An 85-gene model reached an average cross-validated accuracy of 81% and an Area Under the Curve (AUC) of 0.896 for the Receiver Operating Characteristic (ROC) curves. The model also exhibited good inter-stage prognosis prediction performance, with an average AUC of 0.846 for the ROC curves.

Conclusion

The prognosis of lung adenocarcinomas is related with somatic gene mutations. The genetic markers could be used for prognosis prediction and furthermore provide guidance for personal medicine.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5433-7) contains supplementary material, which is available to authorized users.

Impact of the 8th Edition of the UICC-TNM Classification on Clinical Stage 0-IA Lung Adenocarcinoma: Does the New Classification Predict Postoperative Prognosis More Precisely than the Previous One?

PURPOSE

Early lung adenocarcinoma has been more frequently found recently. The 8th edition of the Union for International Cancer Control (UICC)-Tumor Node Metastasis (TNM) classification for lung cancer has been effective since January 2017. This study aims to elucidate advantages of the current classification for patients with clinical stage 0-IA lung adenocarcinoma, in comparison with the older one.

METHODS

We retrospectively reviewed the data of clinical stage IA (7th edition) lung adenocarcinoma patients who underwent surgery at our institute from 2001 to 2012, and reclassified them by the 8th edition. Survival analysis was used to evaluate the impact of the two classifications.

RESULTS

In all, 281 cases were eligible. Clinical T-factors (8th) were significant prognostic factors for overall survival (P = 0.001), recurrence-free survival (P <0.001), and cancer-specific survival (P = 0.001). However, those in the previous edition were not (P = 0.894, P = 0.144, and P = 0.822, respectively).

CONCLUSION

The 8th edition of the UICC-TNM classification predicts postoperative prognosis more precisely than the 7th one in clinical stage 0-IA lung adenocarcinoma. It is probably because the stage distribution of the population, which included in the research project the 8th edition based on, has been changed, and the new edition develops more accurate staging criteria for ground-glass nodule (GGN).

Predictive accuracy of lepidic growth subtypes in early-stage adenocarcinoma of the lung by quantitative CT histogram and FDG-PET

OBJECTIVES

The aim of this study was to analyze the accuracy of computed tomography (CT) and F-18 fluorodeoxyglucose-positron emission tomography/CT (FDG-PET/CT) to distinguish lepidic growth adenocarcinoma (LGA), including adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and lepidic-predominant adenocarcinoma, all of which have favorable survival outcomes, from the more aggressive and invasive non-LGA subtypes.

MATERIALS AND METHODS

We identified 225 patients with c-0/I adenocarcinoma of the lung who underwent PET/CT and 3DCT followed by complete resection. Maximum standardized uptake values (SUVmax) of FDG and several histogram parameters were analyzed. Histological grades were classified according to the predominant subtype (G1: lepidic; G3: micropapillary or solid; and G2: subtypes other than G1/G3).

RESULTS

The proportion of pathological invasive factors (lymphatic vessel involvement/blood vessel invasion/pleural invasion/lymph node metastasis) of patients with preinvasive adenocarcinoma, G1, G2, and G3 tumors were 0%, 3.6%, 48.0%, and 100%, respectively; p <  0.001). Multivariate analysis with CT-related parameters demonstrated that 75^th percentile CT attenuation value (75^th%, p <  0.001) and maximum CT attenuation value (maxCT, p =  0.009) were associated with incidence of non-LGA, whereas the value of SUVmax demonstrated a significant correlation (p <  0.001). When all patients were dichotomized according to ground-glass opacities (GGO)/solid-dominancy for CT maximum diameter, a significant correlation with non-LGA was shown in patients with solid-dominant tumor on SUVmax (p <  0.001) and with GGO-dominant tumor on 75^th% (p =  0.006) and maxCT (p =  0.007). The combination of one of the two significant histogram parameters and SUVmax revealed higher predictive performance for pathological high malignant features (positive pathological invasive factors, non-LGA, and the highly malignant subtype covering G2 with moderately or poorly-differentiated carcinoma and G3) than the individual use of either factor.

CONCLUSION

The 75^th%, maxCT, and SUVmax were highly useful in distinguishing LGA from non-LGA in c-0/I adenocarcinoma.

Predictors of recurrence and survival of pathological T1N0M0 invasive adenocarcinoma following lobectomy

BACKGROUND

This retrospective research was designed to investigate the relationship between pT1N0M0 invasive adenocarcinoma (IADC) harboring solid (SOL) and/or micropapillary (MIP) components and its prognosis following lobectomy.

METHODS

Clinical data of pT1N0M0 IADC patients were retrospectively collected from Shanghai Chest Hospital. Survival curves were plotted by Kaplan-Meier methods. Multivariable cox regressions were conducted to discover the independent risk factors of recurrence-free survival (RFS) and overall survival (OS), through which nomograms were performed to visualize the risk of recurrences and outcomes in personalized information.

RESULTS

Totally, 1965 patients were enrolled, including 248 harboring SOL/MIP and 1717 not. IADC demonstrated worse 5-year RFS (81.9 vs. 92.2%, p < 0.001) and OS (85.7 vs. 94.4%, p < 0.001) when harboring SOL and/or MIP components. And this status became an independent factor associated with poorer RFS (HR 2.445, 95% CI 1.565-3.821, p < 0.001) and OS (HR 2.139, 95% CI 1.180-3.878, p = 0.012) instead of novel classification of IADC predominant patterns. No difference existed between SOL/MIP predominant and minor patterns. In addition, age > 60, smoking, post-chemotherapy and T1b were all indicating poorer RFS and smoking was also related with worse OS. The c-indexes of nomograms were 0.723 for RFS (95% CI, 0.662-0.784) and 0.703 for OS (95% CI, 0.629-0.777) respectively.

CONCLUSIONS

Once the pT1N0M0 IADC harboring SOL/MIP, it strongly indicated the worse clinical recurrence and survival outcome, no matter whether the SOL and/or MIP was predominant. Smoking was correlated with worse prognosis for those patients. Age > 60 and stage T1b also indicated poorer RFS. Whether post-chemotherapy was harmful to pT1N0M0 IADC patients needed further research.

Radiomic analysis of pulmonary ground-glass opacity nodules for distinction of preinvasive lesions, invasive pulmonary adenocarcinoma and minimally invasive adenocarcinoma based on quantitative texture analysis of CT

Objective

To identify the differences among preinvasive lesions, minimally invasive adenocarcinomas (MIAs) and invasive pulmonary adenocarcinomas (IPAs) based on radiomic feature analysis with computed tomography (CT).

Methods

A total of 109 patients with ground-glass opacity lesions (GGOs) in the lungs determined by CT examinations were enrolled, all of whom had received a pathologic diagnosis. After the manual delineation and segmentation of the GGOs as regions of interest (ROIs), the patients were subdivided into three groups based on pathologic analyses: the preinvasive lesions (including atypical adenomatous hyperplasia and adenocarcinoma in situ) subgroup, the MIA subgroup and the IPA subgroup. Next, we obtained the texture features of the GGOs. The data analysis was aimed at finding both the differences between each pair of the groups and predictors to distinguish any two pathologic subtypes using logistic regression. Finally, a receiver operating characteristic (ROC) curve was applied to accurately evaluate the performances of the regression models.

Results

We found that the voxel count feature (P<0.001) could be used as a predictor for distinguishing IPAs from preinvasive lesions. However, the surface area feature (P=0.040) and the extruded surface area feature (P=0.013) could be predictors of IPAs compared with MIAs. In addition, the correlation feature (P=0.046) could distinguish preinvasive lesions from MIAs better.

Conclusions

Preinvasive lesions, MIAs and IPAs can be discriminated based on texture features within CT images, although the three diseases could all appear as GGOs on CT images. The diagnoses of these three diseases are very important for clinical surgery.

HRCT morphological characteristics distinguishing minimally invasive pulmonary adenocarcinoma from invasive pulmonary adenocarcinoma appearing as subsolid nodules with a diameter of ≤3 cm

AIM

To differentiate retrospectively the morphological characteristics at high-resolution computed tomography (CT) between minimally invasive pulmonary adenocarcinoma (MIA) and invasive pulmonary adenocarcinoma (IAC) appearing as subsolid nodules (SNs) with a diameter of ≤3 cm and to provide information to help operative decision-making.

MATERIALS AND METHODS

The patient notes of 260 patients with SNs of ≤3 cm in diameter (98 with MIA and 162 with IAC) confirmed at surgery and histopathology from September 2008 to June 2012 were reviewed retrospectively at the Department of Radiology, Weifang Respiratory Disease Hospital. Sixty-seven patients had pure ground-glass nodules (PGGNs) and 193 had mixed ground-glass nodules (MGGNs). Patients were grouped according to the final pathology: minimally invasive MIA and IAC. The HRCT characteristics were compared between the two groups.

RESULTS

There were statistically significant differences in the pattern, shape, diameter of solid components, proportion of solid components, CT radiodensity values of the ground-glass and solid components, borders, margins, air bronchograms, microvascular signs, and pleural indentations of the nodules between the two groups (all p<0.05). Multivariate and receiver operating characteristic (ROC) analyses indicated significant predictors of MIAs were as follows: small lesion diameter (≤14.7 mm), solid components ≤7 mm, <50% of solid components, low CT radiodensity values of the solid components (≤-107 HU), air bronchograms in the ground-glass opacity components, and microvascular signs.

CONCLUSION

The morphological characteristics at high-resolution CT can be used to differentiate between MIAs and IACs appearing as SNs with a diameter of ≤3 cm and provide information to help operative decision-making.

Prognostic factors in curatively resected pathological stage I lung adenocarcinoma

Background

Patients with pathological stage I (p I) lung adenocarcinoma show variabilities in prognosis even after complete resection. The factors resulting in heterogeneities of prognosis remain controversy. The aim of this study was to identify the risk factors affecting recurrence/metastasis and survival in patients with curatively resected p I lung adenocarcinoma.

Methods

A total of 252 patients with p I lung adenocarcinoma underwent curative resection between January 1st, 2009 to September 30th, 2011 were retrospectively reviewed to analyze the associations of recurrence and survival with the following clinicopathological variables: gender, age, cigarette smoking, family cancer history, tumor size, TNM stage, tumor differentiation, visceral pleural invasion, bronchial involvement, lymphovascular invasion, postoperative adjuvant treatment, pathological subtypes and micropapillary pattern.

Results

Among those 252 patients, 48 had local recurrence or distant metastasis, the rest 204 patients had no relapse until the last follow-up. Cox univariate survival analysis revealed that tumor size (P<0.001), TNM stage [disease-free survival (DFS), P<0.001; overall survival (OS), P=0.004], tumor differentiation (P<0.001), bronchial involvement (P<0.001), lymphovascular invasion (DFS, P=0.021; OS, P=0.001) and micropapillary pattern (DFS, P<0.001; OS, P=0.003) were significantly associated with DFS and OS, while cigarette smoking (P=0.029) and pathological subtypes (P=0.041) were found to be risk factors for DFS either. In multivariate analysis, tumor differentiation (P<0.001) was an independent risk factor for both DFS and OS, TNM stage (P=0.007), bronchial involvement (P=0.004) and micropapillary pattern (P=0.001) only for DFS, while tumor size (P=0.009) and lymphovascular invasion (P=0.010) were found to be independent risk factors only for OS.

Conclusions

Tumor size, TNM stage, tumor differentiation, bronchial involvement, lymphovascular invasion and micropapillary pattern could be considered as risk factors for predicting local recurrence or distant metastasis and survival in curatively resected p I lung adenocarcinoma patients.

Fluorine-18 fluorodeoxyglucose positron emission tomography in the management of solitary pulmonary nodule: a review

Solitary pulmonary nodules are common radiologic findings and their detection has increased due to the introduction and improvement of diagnostics. Since a nodule can be an expression of early lung cancers, a proper classification and management are required because its treatment might lead to decreased morbidity and mortality. In this regard, prominent guidelines are available although they are characterized sometimes by discordant and misleading evidences. Furthermore, the same results of studies in the literature appear conflicting. Aim of this work is to evaluate the role of imaging through an extensive literature review but focusing on 18-fluorine fluorodeoxyglucose positron emission tomography combined with computed tomography (¹⁸F-FDG-PET/CT) in order to assess the limits and future perspectives of solitary pulmonary nodule characterization in early detection of lung cancer. Key messages Detection of solitary pulmonary nodules has increased. Management of solitary pulmonary nodules is still debated. Future perspectives of early solitary pulmonary nodule characterization.

Predictors of primary lung cancer in a solitary pulmonary lesion after a previous malignancy

OBJECTIVE

A solitary pulmonary lesion in patients with a history of malignancy may be either primary lung cancer or a metastatic lung tumor or benign nodule. We retrospectively examined the preoperative predictive factors for determining the type of pathology.

METHODS

We used an exact logistic regression analysis to identify radiological and clinical predictors of primary lung cancer. The study included 187 patients who underwent pulmonary resection for a solitary pulmonary lesion and had received previous treatment for a malignancy.

RESULTS

There were 107 patients with primary lung cancer, 74 with metastatic lung tumors, and 6 with benign lesions. The previous malignancy included colorectal cancer in 71 patients. A disease-free interval exceeding 5 years and ground-glass opacity were found in 27.0% (20/74) and 1.4% (1/74) of metastatic lung tumors, respectively. Multivariate logistic regression analysis demonstrated that spiculation [adjusted odds ratio (a-OR), 1.74; 95% confidence interval (CI), 1.09-2.86], pleural indentation (a-OR 1.99, 95% CI 1.24-3.29), and ground-glass opacity (a-OR 5.28, 95% CI 2.61-13.1) on high-resolution computed tomography, maximum standardized uptake value (a-OR 1.14, 95% CI 1.02-1.29), current and former smokers (a-OR 1.96, 95% CI 1.21-3.30), and previous malignancy other than colorectal cancer (a-OR 2.02, 95% CI 1.26-3.37) were associated with primary lung cancer.

CONCLUSIONS

A combination of radiological findings, smoking history, and type of previous malignancy can improve the ability to predict primary lung cancer in the presence of a solitary pulmonary lesion that appears after previous treatment for a malignancy.

Tumor invasiveness defined by IASLC/ATS/ERS classification of ground-glass nodules can be predicted by quantitative CT parameters

BACKGROUND

To investigate the potential value of CT parameters to differentiate ground-glass nodules between noninvasive adenocarcinoma and invasive pulmonary adenocarcinoma (IPA) as defined by IASLC/ATS/ERS classification.

METHODS

We retrospectively reviewed 211 patients with pathologically proved stage 0-IA lung adenocarcinoma which appeared as subsolid nodules, from January 2012 to January 2013 including 137 pure ground glass nodules (pGGNs) and 74 part-solid nodules (PSNs). Pathological data was classified under the 2011 IASLC/ATS/ERS classification. Both quantitative and qualitative CT parameters were used to determine the tumor invasiveness between noninvasive adenocarcinomas and IPAs.

RESULTS

There were 154 noninvasive adenocarcinomas and 57 IPAs. In pGGNs, CT size and area, one-dimensional mean CT value and bubble lucency were significantly different between noninvasive adenocarcinomas and IPAs on univariate analysis. Multivariate regression and ROC analysis revealed that CT size and one-dimensional mean CT value were predictive of noninvasive adenocarcinomas compared to IPAs. Optimal cutoff value was 13.60 mm (sensitivity, 75.0%; specificity, 99.6%), and -583.60 HU (sensitivity, 68.8%; specificity, 66.9%). In PSNs, there were significant differences in CT size and area, solid component area, solid proportion, one-dimensional mean and maximum CT value, three-dimensional (3D) mean CT value between noninvasive adenocarcinomas and IPAs on univariate analysis. Multivariate and ROC analysis showed that CT size and 3D mean CT value were significantly differentiators. Optimal cutoff value was 19.64 mm (sensitivity, 53.7%; specificity, 93.9%), -571.63 HU (sensitivity, 85.4%; specificity, 75.8%).

CONCLUSIONS

For pGGNs, CT size and one-dimensional mean CT value are determinants for tumor invasiveness. For PSNs, tumor invasiveness can be predicted by CT size and 3D mean CT value.

[Combined use of thin-section CT and 18F-FDG PET/CT for characterization of solitary pulmonary nodules]

OBJECTIVE

To investigate whether fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) combined with thin-section CT improves the diagnostic performance for solitary pulmonary nodules (SPNs).

METHODS

A total of 267 patients underwent examinations with 18F-FDG PET/CT and thin-section CT for evaluating the SPNs with undetermined nature, which was further confirmed by pathological examination or clinical follow-up. The performance of two diagnostic criteria based on findings in PET/CT alone (Criterion 1) and in PET/CT combined with thin-section CT (Criterion 2) were compared.

RESULTS

Thin-section CT provided greater diagnostic information for SPNs in 84.2% of the patients. Compared with Criterion 1, the diagnosis based on Criterion 2 significantly increased the diagnostic sensitivity (80.4% vs 91%, P&lt;0.01) and accuracy (76.4% vs 87.2%, P<0.01) for lung cancer. The lesion size and the CT features including lobulation, air bronchogram, and feeding vessel, but not SUV_max, were all helpful for characterizing non-solid SPNs. Thin-section CT rectified diagnostic errors in 50% (20/40) of the cancerous lesions, which had been diagnosed as benign by PET due to their low metabolism. For non-solid SPNs, Criterion 2 showed a significantly higher diagnostic sensitivity than Criterion 1 (90.0% vs 40.0%, P=0.000) but their diagnostic specificity were comparable (75.2% vs 58.3%, P=0.667). For solid nodules, the use of thin-section CT resulted in no significant improvement in the diagnostic performance (P>0.05).

CONCLUSION

The combination of PET/CT and thin-section CT creates a synergistic effect for the characterization of SPNs, especially non-solid nodules.

Pulmonary ground-glass opacity: computed tomography features, histopathology and molecular pathology

The incidence of pulmonary ground-glass opacity (GGO) lesions is increasing as a result of the widespread use of multislice spiral computed tomography (CT) and the low-dose CT screening for lung cancer detection. Besides benign lesions, GGOs can be a specific type of lung adenocarcinomas or their preinvasive lesions. Evaluation of pulmonary GGO and investigation of the correlation between CT imaging features and lung adenocarcinoma subtypes or driver genes can be helpful in confirming the diagnosis and in guiding the clinical management. Our review focuses on the pathologic characteristics of GGO detected at CT, involving histopathology and molecular pathology.

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.

Concordant and Discordant EGFR Mutations in Patients With Multifocal Adenocarcinomas: Implications for EGFR-Targeted Therapy

PURPOSE

Adenocarcinoma remains the most common subtype of lung cancer in the United States. Most patients present with tumors that are invasive and often metastatic, but in some patients, multiple precursor in situ or minimally invasive adenocarcinoma tumors develop that can be synchronous and metachronous. These precursor lesions harbor the same spectrum of genetic mutations found in purely invasive adenocarcinomas, such as EGFR, KRAS, and p53 mutations. It is less clear, however, whether separate lesions in patients who present with multifocal disease share common underlying genetic driver mutations.

METHODS

Here we review the relevant literature on molecular driver alterations in adenocarcinoma precursor lesions. We then report 4 patients with multifocal EGFR mutant adenocarcinomas in whom we performed molecular testing on 2 separate lesions.

FINDINGS

In 2 of these patients, the mutations are concordant, and in 2 patients, the mutations are discordant. A review of the literature demonstrates increasing evidence that lesions with discordant mutations may confer a more favorable prognosis because they are unlikely to represent metastases.

IMPLICATIONS

Our findings suggest that the emergence of the dominant EGFR driver alteration is often independent between lesions in patients with multifocal adenocarcinomas, and thus the same targeted therapy may not be effective for all lesions. However, genetic testing of multiple lesions can help to distinguish separate primary tumors from metastatic disease.

Value of Ki-67 and computed tomography in the assessment of peripheral lung adenocarcinoma

PURPOSE

This study was designed to determine whether proliferation antigen Ki-67 and/or a computed tomography (CT) value could be used to evaluate the clinical-pathological features of peripheral lung adenocarcinoma.

MATERIALS AND METHODS

A total of 116 eligible lung cancer patients were enrolled. Nodule size, lymph node metastasis, differentiation, Ki-67 expression and CT findings were assessed. The relationship between clinic parameters and the CT feature was analysed statistically.

RESULTS

The percentage of lesions that had ground-glass opacity or localised air bronchogram was significantly greater in low CT value group (<30, p < 0.05). No significant association was observed between CT value and size in the subgroup with CT value > 0 (p = 0.66). As a proliferative marker of lung cancer, Ki-67 was present in a total of 115 (99.9%) of the 116 evaluable primary lung cancers. There was a statistically significant correlation between the Ki-67 index and CT value (p < 0.05). Compared to CT value, Ki-67 index possessed higher sensitivity to predict the differentiation and lymph node metastasis of peripheral lung adenocarcinoma, adding of CT value would enhance its specificity.

CONCLUSION

Combination of Ki-67 expression and CT value determination was useful for the classification of differentiation and metastatic or proliferative potential of peripheral lung adenocarcinoma.

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.

Prognostic role of p53 and Ki-67 immunohistochemical expression in patients with surgically resected lung adenocarcinoma: a retrospective study

OBJECTIVE

p53 mutations and the Ki-67 protein are frequently observed in various types of human cancer; the abnormal expression of p53 and Ki-67 in the tumor is associated with poor survival of lung cancer patients. We aimed to assess the prognostic role of immunohistochemical (IHC) expression of p53 and Ki-67 in lung adenocarcinoma tissue.

METHODS

Tumor samples from 136 patients who had undergone surgical resection for lung adenocarcinoma were retrospectively evaluated for p53 and Ki-67 expression by immunohistochemistry. Associations of clinical and pathologic variables with p53 and Ki-67 were determined using the χ(2) test. After excluding two patients (follow-up loss), 134 cases were evaluated for associations between p53, Ki-67, clinical and pathologic variables, and survival by using the Cox proportional hazards regression model and Kaplan-Meier method.

RESULTS

In the 136 patients, p53 was positive in 71.0% (93/131), and Ki-67 showed high in 49.2% (61/124). Unlike p53, Ki-67 was associated with male sex, smoking, and poor tumor differentiation (P=0.004, P=0.001 and P=0.006). Of these, poor tumor differentiation strongly was correlated with high level of Ki-67 expression (P=0.008). Neither p53 nor Ki-67 was associated with increased risk of death (P=0.318, P=0.053); however, age ≥60 years and lymph node involvement were significant predictors of death (P=0.039 and P=0.042). The log-rank test revealed a significant association between Ki-67 and lower survival in all patients (χ(2)=5637; P=0.018); however, the risk was limited to stage III cases (χ(2)=5.939; P=0.015). Unlike p53, patients with high level of Ki-67 expression showed lower 3-year actuarial survival than those without (log-rank test, χ(2)=4.936; P=0.026).

CONCLUSIONS

IHC expression of Ki-67 in lung adenocarcinoma tissue shows stronger association with poor tumor differentiation, and negatively affects patients' survival in advanced-stage lung cancer; however, the role of p53 on patient outcome needs further study.

Imaging the solitary pulmonary nodule

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