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

Air bronchogram on chest CT in radiological pure-solid appearance lung cancer: Correlation analysis with genetic pathological features and survival outcomes

PURPOSE

To investigate the correlation of air bronchogram sign with clinicopathological characteristics and prognosis in patients with clinical stage (c-stage) I non-small cell lung cancer (NSCLC) with radiological pure-solid appearance.

METHOD

We retrospectively evaluated 276 patients with pure-solid c-stage I NSCLC and assessed the correlation between the air bronchogram and clinicopathological characteristics. A Cox proportional hazards model was performed to identify the effect of air bronchogram and clinicopathological variables on oncological outcomes. Recurrence-free survival (RFS) and overall survival (OS) were calculated by Kaplan-Meier curves and were compared using log-rank tests.

RESULTS

Presence of air bronchogram was associated with a well differentiated degree (P =.026), higher incidence of EGFR mutation (P <.001) and lower recurrence(P =.021). Kaplan-Meier survival curves showed that air bronchogram group was associated with favorable RFS(67.0% vs. 50.2%; P =.015). A multivariable analysis revealed that air bronchogram and EGFR mutation were independent significant prognostic factors associated with RFS (hazard ratio [HR] = 0.495, 95% confidence interval [CI]: 0.322-0.761, P =.001; HR = 1.625, 95% CI: 1.074-2.457, P =.021; respectively), but not with OS. Additionally, we found that pathological lymph node metastasis was identified as an independent prognostic factor associated with poor RFS and OS(HR = 2.808, 95% CI: 1.913-4.123, P <.001 for RFS; HR = 1.983, 95% CI: 1.185-3.318, P =.009 for OS).

CONCLUSIONS

Presence of air bronchogram was associated with well differentiated degree, higher incidence of EGFR mutation and had additional positive prognostic value for RFS in c-stage I NSCLC with a radiological pure-solid appearance.

Potential of artificial intelligence based on chest computed tomography to predict the nature of part-solid nodules

BACKGROUND

The potential of artificial intelligence (AI) to predict the nature of part-solid nodules based on chest computed tomography (CT) is still under exploration.

OBJECTIVE

To determine the potential of AI to predict the nature of part-solid nodules.

METHODS

Two hundred twenty-three patients diagnosed with part-solid nodules (241) by chest CT were retrospectively collected that were divided into benign group (104) and malignant group (137). Intraclass correlation coefficient (ICC) was used to assess the agreement in predicting malignancy, and the predictive effectiveness was compared between AI and senior radiologists. The parameters measured by AI and the size of solid components measured by senior radiologists were compared between two groups. Receiver operating characteristic (ROC) curve was chosen for calculating the Youden index of each quantitative parameter, which has statistical significance between two groups. Binary logistic regression performed on the significant indicators to suggest predictors of malignancy.

RESULTS

AI was in moderate agreement with senior radiologists (ICC = 0.686). The sensitivity, specificity and accuracy of two groups were close (p > 0.05). The longest diameter, volume and mean CT attenuation value and the largest diameter of solid components between benign and malignant groups were different significantly (p < 0.001). Logistic regression analysis showed that the longest diameter and mean CT attenuation value and the largest diameter of solid components were indicators for malignant part-solid nodules, the threshold of which were 9.45 mm, 425.0 HU and 3.45 mm, respectively.

CONCLUSION

Potential of quantitative parameter measured by AI to predict malignant part-solid nodules can provide a certain value for the clinical management.

Molecular typing of lung adenocarcinoma with computed tomography and CT image-based radiomics: a narrative review of research progress and prospects

Objective

The purpose of this paper was to perform a narrative review of current research evidence on conventional computed tomography (CT) imaging features and CT image-based radiomic features for predicting gene mutations in lung adenocarcinoma and discuss how to translate the research findings to guide future practice.

Background

Lung cancer, especially lung adenocarcinoma, is the leading cause of cancer-related deaths. With advances in the diagnosis and treatment of lung adenocarcinoma with the emergence of molecular testing, the prediction of oncogenes and even drug resistance gene mutations have become key to individualized and precise clinical treatment in order to prolong survival and improve quality of life. The progress of imageological examination includes the development of CT and radiomics are promising quantitative methods for predicting different gene mutations in lung adenocarcinoma, especially common mutations, such as epidermal growth factor receptor (EGFR) mutation, anaplastic lymphoma kinase (ALK) mutation and Kirsten rat sarcoma viral oncogene (KRAS) mutation.

Methods

The PubMed electronic database was searched along with a set of terms specific to lung adenocarcinoma, radiomics (including texture analysis), CT, computed tomography, EGFR, ALK, KRAS, rearranging transfection (RET) rearrangement and c-ros oncogene 1 (ROS-1), v-raf murine sarcoma viral oncogene homolog B1 (BRAF), and human epidermal growth factor receptor 2 (HER2) mutations et al. This review has been reported in compliance with the Narrative Review checklist guidelines. From each full-text article, information was extracted regarding a set of terms above.

Conclusions

Research on the application of conventional CT features and CT image-based radiomic features for predicting the gene mutation status of lung adenocarcinoma is still in a preliminary stage. Noninvasively determination of mutation status in lung adenocarcinoma before targeted therapy with conventional CT features and CT image-based radiomic features remains both hopes and challenges. Before radiomics could be applied in clinical practice, more work needs to be done.

Risk factors for lymph node metastasis and surgical scope in patients with cN0 non-small cell lung cancer: a single-center study in China

BACKGROUND

It is difficult to determine the lymph node metastasis of patients with clinically negative lymph nodes (cN0) non-small cell lung cancer (NSCLC) before surgery. The purpose of this study is to investigate risk factors of lymph node metastasis in cN0 NSCLC, thereby to identify the surgical indications for lymph node dissection in cN0 NSCLC.

METHODS

We conducted a retrospective study of patients with tumor size ≤ 30 mm who underwent radical resection of NSCLC. Binary logistic regression analysis was applied to predict risk factors for lymph node metastasis, and subject operating characteristics (ROC) curve was used to evaluate the independent risk factors.

RESULTS

Overall, 44 patients (6.8%) with cN0 NSCLC had lymph node metastasis. Factors of tumor consolidation diameter (p < 0.001) and preoperative serum carcinoembryonic antigen (CEA) level (p = 0.017) are independent risk factors lymph node metastasis in cN0 NSCLC. The ROC curve showed that the cut-off value of consolidation diameter was 16.5 mm, and the area under the curve (AUC) was 0.825 (p < 0.001, 95% CI 0.780-0.870); the cut-off value of serum CEA level was 1.765 μg/L, and the AUC was 0.661 (p < 0.001, 95% CI: 0.568-0.754). Moreover, 8 of 461 patients with tumor parenchyma ≤ 16.5 mm had lymph node metastasis, and 36 of 189 patients with tumor parenchyma > 16.5 mm had lymph node metastasis.

CONCLUSION

Tumor consolidation diameter and preoperative serum CEA are independent factors to predict cN0 NSCLC with tumor size ≤ 30 mm. For patients with tumor parenchyma > 16.5 mm, the probability of lymph node metastasis is higher and lymph node dissection is recommended. For patients with tumor parenchyma ≤ 16.5 mm, the probability of lymph node metastasis is lower and lymph node sampling is feasible.

Predicting the histological invasiveness of pulmonary adenocarcinoma manifesting as persistent pure ground-glass nodules by ultra-high-resolution CT target scanning in the lateral or oblique body position

Background

Ultra-high-resolution computed tomography (U-HRCT) has improved image quality for displaying the detailed characteristics of disease states and lung anatomy. The purpose of this study was to retrospectively examine whether U-HRCT target scanning in the lateral or oblique body position (protocol G scan) could predict histological invasiveness of pulmonary adenocarcinoma manifesting as pure ground-glass nodules (pGGNs).

Methods

From January 2015 to December 2016, 260 patients with 306 pathologically confirmed pGGNs who underwent preoperative protocol G scans were retrospectively reviewed and analyzed. The U-HRCT findings of preinvasive lesions [atypical adenomatous hyperplasias (AAH) and adenocarcinomas in situ (AIS)] and invasive pulmonary adenocarcinomas [minimally invasive adenocarcinomas (MIA) and invasive adenocarcinomas (IAC)] were manually compared and analyzed using orthogonal multiplanar reformation (MPR) images. The logistic regression model was established to determine variables that could predict the invasiveness of pGGNs. Receiver operating characteristic (ROC) curve analysis was performed to evaluate their diagnostic performance.

Results

There were 213 preinvasive lesions (59 AAHs and 154 AISs) and 93 invasive pulmonary adenocarcinomas (53 MIAs and 40 IACs). Compared with the preinvasive lesions, invasive adenocarcinomas exhibited a larger diameter (13.5 vs. 9.3 mm, P=0.000), higher mean attenuation (-571 vs. -613 HU, P=0.002), higher representative attenuation (-475 vs. -547 HU, P=0.000), lower relative attenuation (-339 vs. -292 HU, P=0.000) and greater frequencies of heterogeneity (P=0.001), air bronchogram (P=0.000), bubble lucency (P=0.000), and pleural indentation (P=0.000). Multiple logistic analysis revealed that larger diameter [odds ratio (OR), 1.328; 95% CI: 1.208-1.461; P=0.000] and higher representative attenuation (OR, 1.005; 95% CI: 1.003-1.007; P=0.000) were significant predictive factors of invasive pulmonary adenocarcinomas from preinvasive lesions. The optimal cut-off value of the maximum diameter for invasive pulmonary adenocarcinomas was larger than 10 mm (sensitivity, 66.7%; specificity, 72.8%).

Conclusions

The imaging features based on protocol G scanning can effectively help predict the histological invasiveness of pGGNs. The maximum diameter and representative attenuation are important parameters for predicting invasiveness.

Should sublobar resection be offered for screening-detected lung nodules?

The increasing use of low-dose CT for screening for lung cancer will inevitably identify many small, asymptomatic lung nodules and ground-glass opacities (GGOs). Current guidelines for the management of screening-detected lesions tend to advise a conservative approach based on serial imaging and intervention only if ‘suspicious’ features emerge. However, more recent developments in thoracic surgery and in the understanding of the screening-detected lesions themselves prompt some pertinent questions over this conservatism. Is CT surveillance sufficiently reliable to exclude malignancy? Is it really necessary to hold back on operative biopsy and resection given modern surgical safety and efficacy? Is the option for early surgical therapy a viable one—especially with the availability of sublobar resection today? Modern data suggests that the risk of inaction for some screening-detected lesions may be higher than expected, whereas the potential harm of surgical intervention may be substantially reduced by sublobar resection and the latest minimally invasive surgical techniques. A more pro-active approach towards offering surgery for screening-detected lesions should now be considered.

Diagnostic performance for pulmonary adenocarcinoma on CT: comparison of radiologists with and without three-dimensional convolutional neural network

OBJECTIVES

To compare diagnostic performance for pulmonary invasive adenocarcinoma among radiologists with and without three-dimensional convolutional neural network (3D-CNN).

METHODS

Enrolled were 285 patients with adenocarcinoma in situ (AIS, n = 75), minimally invasive adenocarcinoma (MIA, n = 58), and invasive adenocarcinoma (IVA, n = 152). A 3D-CNN model was constructed with seven convolution-pooling and two max-pooling layers and fully connected layers, in which batch normalization, residual connection, and global average pooling were used. Only the flipping process was performed for augmentation. The output layer comprised two nodes for two conditions (AIS/MIA and IVA) according to prognosis. Diagnostic performance of the 3D-CNN model in 285 patients was calculated using nested 10-fold cross-validation. In 90 of 285 patients, results from each radiologist (R1, R2, and R3; with 9, 14, and 26 years of experience, respectively) with and without the 3D-CNN model were statistically compared.

RESULTS

Without the 3D-CNN model, accuracy, sensitivity, and specificity of the radiologists were as follows: R1, 70.0%, 52.1%, and 90.5%; R2, 72.2%, 75%, and 69%; and R3, 74.4%, 89.6%, and 57.1%, respectively. With the 3D-CNN model, accuracy, sensitivity, and specificity of the radiologists were as follows: R1, 72.2%, 77.1%, and 66.7%; R2, 74.4%, 85.4%, and 61.9%; and R3, 74.4%, 93.8%, and 52.4%, respectively. Diagnostic performance of each radiologist with and without the 3D-CNN model had no significant difference (p > 0.88), but the accuracy of R1 and R2 was significantly higher with than without the 3D-CNN model (p < 0.01).

CONCLUSIONS

The 3D-CNN model can support a less-experienced radiologist to improve diagnostic accuracy for pulmonary invasive adenocarcinoma without deteriorating any diagnostic performances.

KEY POINTS

• The 3D-CNN model is a non-invasive method for predicting pulmonary invasive adenocarcinoma in CT images with high sensitivity. • Diagnostic accuracy by a less-experienced radiologist was better with the 3D-CNN model than without the model.

Lung Adenocarcinoma at CT with 0.25-mm Section Thickness and a 2048 Matrix: High-Spatial-Resolution Imaging for Predicting Invasiveness

Background High-spatial-resolution (HSR) CT provides detailed information and clear delineation of lung anatomy and disease states. HSR CT may have high diagnostic performance for predicting invasiveness of lung adenocarcinoma. Purpose To examine the diagnostic performance of HSR CT in predicting the invasiveness of lung adenocarcinoma. Materials and Methods In this retrospective study, 89 consecutive patients with adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), or invasive adenocarcinoma (IVA) were included who underwent surgery for lung cancer between January 2018 and December 2019. All patients underwent HSR CT with 0.25-mm section thickness and a 2048 matrix. Two independent observers evaluated the images for the presence or absence of the following HSR CT findings: lobulation, spiculation, pleural indentation, vessel convergence, homogeneity of ground-glass opacity, reticulation, irregularity and centrality of solid portion, and air bronchiologram (irregularity, disruption, or dilatation). The total diameter (≤1.6 cm or >1.6 cm) and the longest diameter of the solid portion (≤0.8 cm or >0.8 cm) were evaluated. Logistic regression models were used to identify findings associated with MIA plus IVA. Receiver operating characteristic analysis was performed to determine diagnostic performance. Results Eighty-nine patients (mean, 69 years ± 11 [standard deviation]; 49 men) were evaluated. The size of the nodules with invasion was a mean of 2.5 cm ± 1.2. Univariable analysis revealed lobulation, spiculation, pleural indentation, irregular and central solid portion, air bronchiologram with disruption and/or irregular dilatation, and total and solid portion diameters as associated with MIA plus IVA (all, P < .05). After adjustment for age, sex, and pack-years of smoking, disruption of air bronchogram and solid portion diameter greater than 0.8 cm remained as predictors of invasiveness (P = .001 and P = .02, respectively). The diagnostic performance of these two findings combined were as follows: sensitivity of 97% (59 of 61 patients; 95% confidence interval: 94%, 100%) and specificity of 86% (19 of 22 patients; 95% confidence interval: 65%, 97%), with an area under the curve of 0.94. Conclusion Using high-spatial-resolution CT, disruption of air bronchiologram and a solid portion greater than 0.8 cm were independently associated with a greater likelihood of invasiveness in lung adenocarcinoma. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Lynch and Oh in this issue.

Predictive Factors for Lymph Node Metastasis in Clinical Stage I Part-Solid Lung Adenocarcinoma

BACKGROUND

Accurate clinical staging of tumors with a small solid portion is essential for developing an appropriate treatment plan. This study evaluated predictive factors for lymph node (LN) metastasis in patients with clinical stage I part-solid lung adenocarcinoma.

METHODS

Medical records of patients with clinical stage I part-solid adenocarcinoma who underwent anatomic pulmonary resection with systematic node evaluation between January 2009 and June 2018 were retrospectively reviewed. To identify predictive factors for LN metastasis, univariate and multivariable logistic regression analyses were performed.

RESULTS

Among the 593 patients in this study, the overall prevalence of LN metastasis was 3.7% (n = 22), which included 3.0% (n = 18) of patients with N1 LN metastasis and 1.5% (n = 9) of patients with N2 LN metastasis. Combined N1 and N2 nodal involvement was observed in 5 patients. Nodal metastasis was not observed in tumors with a solid portion sized 1.1 cm or smaller. The nodal metastasis rates in cT1b, cT1c, and cT2a tumors were 5.5% (13 of 237), 7.1% (6 of 84), and 13.6% (3 of 22), respectively. According to the multivariable analysis, predictive factors included the size of the solid portion (P = .015) and the high maximum standardized uptake value (SUVmax) of the primary tumor (P = .044).

CONCLUSIONS

Large solid portion and high SUVmax of the primary tumor were predictive factors of LN metastasis in patients with clinical stage I part-solid lung adenocarcinoma. Systematic LN evaluation should be performed, especially in those who have a large solid portion and high SUVmax of the primary tumor.

Invasiveness and surgical timing evaluation by clinical features of ground-glass opacity nodules in lung cancers

Background

The early stages of lung cancer with ground‐glass opacity (GGO) pattern are detectable. However, it remains a challenge for physicians how best to treat GGO nodules as invasive tumors are occasionally found, even in pure GGO nodules. This study identified the invasiveness by the clinical features of the GGO nodules.

Methods

A retrospective review of patients with resected GGO nodules from August 2015 to February 2019 was performed. A total of 92 patients were enrolled and gender, age, tumor location, operation times, tumor size, histopathologic and radiological findings were analyzed.

Results

In this study, the sequential of GGO nodules invasiveness was significantly related to the tumor size and solid component. After regrouping the population into preinvasive and invasive groups, the invasiveness was significantly related to tumor size, solid component, tumor volume and maximal computed tomography (CT) value.

Conclusions

The invasiveness is difficult to evaluate according to the CT features only when the GGO nodules are less than 2 cm and consolidation/tumor ratio (C/T ratio) are less than 0.25. Tumor size and solid component are significant factors for predicting invasiveness. Part‐solid GGO nodules with a diameter greater than 1 cm require surgical consideration due to their high risk of invasiveness.

Verification of T descriptor with consolidation size for sub-centimeter non-small cell lung cancer

PURPOSE

In the most recent (eighth) edition of the TNM classification, the clinical T descriptor has been adapted to measure the consolidation size of sub-solid lung cancer. Sub-centimeter non-small cell lung cancer (NSCLC) has thereby been subclassified into three groups: Tis, T1mi, and T1a; however, the revision has not been validated well. Thus, we investigated the clinicopathological characteristics and long-term oncological outcomes of sub-centimeter NSCLCs based on the solid size.

METHODS

The subjects of this retrospective review were 99 patients who underwent complete resection for NSCLC with ≤ 1 cm in consolidation size on computed tomography (CT). Survival was reanalyzed after reclassification according to the new TNM classification.

RESULTS

This cohort consisted of 14 patients with cTis tumors, 18 with cT1mi tumors, and 67 with cT1a tumors. Among the patients with tumors classified as cT1a, two had lymph node metastasis and two had vascular invasion. The cumulative incidences of recurrence at 5 and 10 years were 0% for cTis/cT1mi tumors, and 4.5% and 6.1% for cT1a tumors, respectively.

CONCLUSIONS

There may be pathological and survival differences between cTis/cT1mi tumors and cT1a tumors, but not between cTis tumors and cT1mi tumors.

Outcomes and predictive factors for pathological node-positive in radiographically pure-solid, small-sized lung adenocarcinoma

OBJECTIVES

The indication of limited resection for radiographically pure-solid, small-sized lung adenocarcinoma is controversial. This study aimed to reveal the long-term outcome of standard surgical treatment and determine the predictive factors for pathological lymph node metastasis in optimal candidates undergoing limited surgical resection for pure-solid, small-sized lung adenocarcinoma.

METHODS

The medical records of 107 consecutive patients were retrospectively reviewed at our hospital between December 2002 and December 2013. Inclusion criteria were histopathological diagnosis of lung adenocarcinoma, radiographically pure-solid tumor, ≤ 2 cm tumor size measured using thin-section computed tomography, clinical N0M0, patients who underwent lobectomy with systematic or lobe-specific lymph node dissection, and R0 resection. Overall and disease-free survival curves were calculated using the Kaplan-Meier method. Clinicopathological factors predicting pathological node-positive metastasis were identified by univariate and multivariate analysis.

RESULTS

The 5-year overall and disease-free survival rates were 91.4% and 87.3%, respectively. Multivariate analysis demonstrated maximum standardized uptake value > 5 as the independent predictor of pathological node-positive metastasis (odds ratio 3.81; 95% confidence interval 1.25-12.3; p = 0.02). In all patients, the pathological node-positive rate was 16.7%; in patients who had a maximum standardized uptake value of ≤ 5, the rate was 7.9%.

CONCLUSION

The long-term outcome of standard surgical treatment was favorable. Maximum standardized uptake value was a significant predictor of pathological node-positive metastasis; however, diagnostic accuracy was not favorable. Therefore, the selection of optimal candidates is difficult, and limited surgical resection may not be applicable in pure-solid, small-sized lung adenocarcinoma.

A Proposal for Restaging of Invasive Lung Adenocarcinoma Manifesting as Pure Ground Glass Opacity

BACKGROUND

Invasive lung adenocarcinoma (IAC) occurs in 22.8% to 40.4% of pure ground-glass opacity (GGO) cases. This study assessed the malignancy and survival outcomes of IAC manifesting as pure GGO with the aim of providing suggestions on T staging of these tumors.

METHODS

From January 2010 to December 2012, the study focused on 109 cases of IAC that radiologically manifested as pure GGO. For comparison, 305 clinical stage IA part-solid IACs were also included. Clinicopathological characteristics, managements, and prognoses were evaluated.

RESULTS

As compared with part-solid nodules, pure GGOs showed lower T stage, lower N stage, smaller invasive size, less invasive predominant components, and better survival. Long-term outcomes were independently influenced by whether the tumors presented as pure GGO. For the pure GGO group, the 5-year overall and disease-free survival rates were 100% and 99.1%, respectively. The pT stage, invasive size, and predominant component type did not influence survival.

CONCLUSIONS

IAC radiologically manifesting as pure GGO is a group of tumors with low-grade malignancies and excellent prognosis. External validation is needed to assess whether it should be restaged in the TNM classification of non-small lung cancers.

Consolidation/Tumor Ratio on Chest Computed Tomography as Predictor of Postoperative Nodal Upstaging in Clinical T1N0 Lung Cancer

BACKGROUND

In clinical T1N0 peripheral lung cancers, lymph node upstaging is occasionally encountered postoperatively. However, nodal upstaging is rare in lung cancers presenting as ground-glass opacities. The aim of this study was to determine if lymph node upstaging could be reliably extrapolated from parameters such the consolidation/tumor ratio of chest computed tomography.

METHODS

We conducted a retrospective study of 486 patients treated for peripheral clinical T1N0 non-small cell lung cancer, each undergoing lobectomy with mediastinal lymph node dissection. We compared preoperative variables in the pathologic N0 and nodal upstaging groups, analyzing such variables to determine factors predictive of lymph node upstaging.

RESULTS

Of the 486 patients studied, lymph node upstaging occurred in 42 (8.6%). In the upstaging group, the mean nodule diameter exceeded that of the pathologic N0 group (2.3 vs 1.9 cm, respectively; p < 0.001), and the mean consolidation/tumor ratio was larger in the upstaging group than the pN0 group (0.95 vs 0.68, respectively; p < 0.001). Nodule diameter and consolidation/tumor ratio emerged as significant predictive factors for lymph node upstaging after surgery in a multivariate analysis (hazard ratio [HR] 2.259, p = 0.039; HR 173.645, p = 0.001, respectively).

CONCLUSIONS

Consolidation/tumor ratio and nodule diameter are significant predictive factors of postoperative lymph node upstaging. The higher the consolidation/tumor ratio and smaller the nodule diameter, the less likely the occurrence of postoperative lymph upstaging would be in clinical T1N0 peripheral non-small cell lung cancer.

Predictive factors for invasive adenocarcinoma in patients with clinical non-invasive or minimally invasive lung cancer

Background

Pure ground glass opacity (GGO) or part-solid GGO with small solid component (≤5 mm) are likely to be non-invasive or minimally invasive lung cancer. However, those lesions sometimes are diagnosed as invasive adenocarcinoma postoperatively. The aim of this study was to determine the predictors of invasive adenocarcinoma in clinical non- or minimally invasive lung cancer.

Methods

From January 2010 to December 2017, 203 patients were diagnosed as clinical adenocarcinoma in situ (AIS) or minimally invasive adenocarcinoma (MIA) identified on chest computed tomography (CT) and they underwent surgical resection. A retrospective study was performed to analyze the prediction of invasive adenocarcinoma in clinical non- or minimally invasive lung cancer.

Results

Of all clinical AIS or MIA patients, invasive adenocarcinoma was diagnosed in 55 patients (27.1%). In clinical AIS, invasive adenocarcinoma was diagnosed in 19 patients (17.9%) and 36 patients (37.1%) were diagnosed as invasive adenocarcinoma in clinical MIA (P=0.002). Tumor diameter and the presence of solid component were confirmed to be significant predictive factors for invasive adenocarcinoma in a multivariate analysis [hazard ratio (HR) 1.071, P=0.037; HR 2.573, P=0.005; respectively].

Conclusions

Large tumor size and the presence of solid component in clinical AIS or MIA are predictive factors for invasive adenocarcinoma. Therefore, early surgical intervention is recommended for those lesions.

[Shanghai Pulmonary Hospital Experts Consensus on the Management of Ground-Glass Nodules Suspected as Lung Adenocarcinoma (Version 1)]

随着胸部计算机断层扫描（computed tomography, CT）检查，尤其是低剂量薄层CT筛查项目在中国的广泛开展，越来越多的无症状肺部磨玻璃结节（ground-glass nodules, GGNs）被发现。虽然国内及国际上已发布了一系列针对肺部GGNs的指南，但是这些指南的撰写者多来自呼吸、肿瘤及影像专业，可能缺乏对现代微创胸外科的充分认识，造成外科手术在肺部GGNs诊治中的作用不明确，甚至被低估；而且，肺部肿瘤相关的各学科对于早期肺癌，尤其是浸润前病变的处理也缺乏统一规范。因此，基于国内外现有文献及上海市肺科医院多年积累的经验，上海市肺科医院撰写了此诊疗共识。本共识推荐对于疑似肺腺癌的GGNs进行多学科评估，依据诊断，选择合理的处置方式。对于疑似原位腺癌，推荐进行胸部薄层CT随访，或在特定情况下进行不超过肺段切除的限制性肺切除；对于疑似微浸润腺癌，推荐进行限制性肺切除或肺叶切除；对于疑似浸润性腺癌，建议依据病灶是否含有磨玻璃成分、位置、大小、个数及患者躯体情况选择合理的手术方式；而肺多发结节的处理原则推荐为主病灶优先，兼顾次要病灶，综合选择治疗方案。

Prognostic prediction of clinical stage IA lung cancer presenting as a pure solid nodule

Background

Clinical stage IA lung cancer presenting as a ground glass opacity (GGO) on imaging is known to be associated with a good prognosis. Conversely, the prognosis of lung cancer presenting as a pure solid nodule is less favorable. The purpose of this study was to identify the predictive factors affecting prognosis in pure solid nodule lung cancer.

Methods

A total of 328 consecutive patients undergoing curative resection of clinical stage IA pure solid nodule lung cancer were reviewed retrospectively. Recurrence, survival and risk factors for nodal upstaging were analyzed.

Results

Of the 328 patients, 277 patients (84.6%) underwent lobectomy (or greater) and 51 patients (15.6%) underwent sublobar resection. Mediastinal lymph node dissection or sampling was performed in 278 patients (84.8%). The 5-year recurrence-free survival rate was 70.0% and the disease-specific survival rate was 86.5%. Intraoperative mediastinal lymph node dissection was the only significant related factor for recurrence and cancer-related death in a multivariate analysis [hazard ratio (HR) =0.485, P=0.020; HR =0.342, P=0.014]. A total of 217 patients underwent lobectomy with mediastinal lymph node dissection and nodal upstaging occurred in 36 patients (16.6%). There were no significant predictive factors for nodal upstaging in a multivariate analysis. Visceral pleural invasion, lymphovascular invasion, and small cell carcinoma histology were the only identified risk factors for nodal upstaging (HR =3.858, P=0.006; HR =8.792, P<0.001; HR =45.908, P=0.017).

Conclusions

There were no definite factors predictive of prognosis in clinical stage IA pure solid nodule lung cancer. Only accurate pathologic staging and adequate intraoperative lymph node dissection were shown to be related to prognosis.

Radiologic-Pathologic Correlation of Solid Portions on Thin-section CT Images in Lung Adenocarcinoma: A Multicenter Study

BACKGROUND

Measuring the size of invasiveness on computed tomography (CT) for the T descriptor size was deemed important in the 8th edition of the TNM lung cancer classification. We aimed to correlate the maximal dimensions of the solid portions using both lung and mediastinal window settings on CT imaging with the pathologic invasiveness (> 0.5 cm) in lung adenocarcinoma patients.

MATERIALS AND METHODS

The study population consisted of 378 patients with a histologic diagnosis of adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), invasive adenocarcinoma (IVA)-lepidic, IVA-acinar and/or IVA-papillary, and IVA-micropapillary and/or solid adenocarcinoma. A panel of 15 radiologists was divided into 2 groups (group A, 9 radiologists; and group B, 6 radiologists). The 2 groups independently measured the maximal and perpendicular dimensions of the solid components and entire tumors on the lung and mediastinal window settings. The solid proportion of nodule was calculated by dividing the solid portion size (lung and mediastinal window settings) by the nodule size (lung window setting). The maximal dimensions of the invasive focus were measured on the corresponding pathologic specimens by 2 pathologists.

RESULTS

The solid proportion was larger in the following descending order: IVA-micropapillary and/or solid, IVA-acinar and/or papillary, IVA-lepidic, MIA, and AIS. For both groups A and B, a solid portion > 0.8 cm in the lung window setting or > 0.6 cm in the mediastinal window setting on CT was a significant indicator of pathologic invasiveness > 0.5 cm (P < .001; receiver operating characteristic analysis using Youden's index).

CONCLUSION

A solid portion > 0.8 cm on the lung window setting or solid portion > 0.6 cm on the mediastinal window setting on CT predicts for histopathologic invasiveness to differentiate IVA from MIA and AIS.

Solitary ground-glass opacity nodules of stage IA pulmonary adenocarcinoma: combination of 18F-FDG PET/CT and high-resolution computed tomography features to predict invasive adenocarcinoma

To investigate the performance of combined 18F-FDG Positron Emission Tomography/Computed Tomography with high-resolution CT for differentiating invasive adenocarcinoma from adenocarcinoma in situ (pre-invasive lesion) or minimally invasive adenocarcinoma in stage IA lung cancer patients with solitary ground-glass opacity nodules. This retrospective study enrolled 58 consecutive stage IA pulmonary adenocarcinoma patients with solitary ground-glass opacity nodules. The characteristics and measurements of the ground-glass opacity nodules as pure ground-glass opacity nodules and mixed ground-glass opacity nodules in the pre-invasive or minimally invasive adenocarcinoma and invasive adenocarcinoma groups on Positron Emission Tomography/Computed Tomography and high-resolution CT were compared and analyzed. Ground-glass opacity nodules in the pre-invasive or minimally invasive adenocarcinoma group preferentially manifested as pure ground-glass opacity nodule (p < 0.01) compared to the invasive adenocarcinoma group. While cystic appearance was more common in the invasive adenocarcinoma group (p < 0.05). Significant differences were found in the diameter of the ground-glass opacity nodule itself and its solid component, and consolidation/tumor ratio between the two groups. The sensitivity in predicting invasive adenocarcinoma was higher with a combined consolidation/tumor ratio > 0.38 and SUV_max > 1.46 in mixed ground-glass opacity nodule when compared to those of SUV_max > 0.95 alone or consolidation/tumor ratio> 0.39 alone (both p > 0.05). For a mixed ground-glass opacity nodule combined consolidation/tumor ratio > 0.38 and SUV_max > 1.46 appears to better predict invasive adenocarcinoma in stage IA lung cancer patients with solitary ground-glass opacity nodules.

Sublobar Resection Margin Width Does Not Affect Recurrence of Clinical N0 Non-small Cell Lung Cancer Presenting as GGO-Predominant Nodule of 3 cm or Less

BACKGROUND

Sublobar resection of lung cancer may benefit patients with lung cancer presenting as ground-glass opacity (GGO) nodules. The purpose of this study was to evaluate the effect of margin width on recurrence after sublobar resection in patients with clinical N0 non-small cell lung cancer presenting as GGO-predominant nodule.

METHODS

We conducted a retrospective chart review of 91 patients treated for clinical N0 non-small cell lung cancer ≤3 cm by sublobar resection with clear resection margins. We assigned them to two groups: GGO-predominant tumor and solid-predominant tumor. Each group was subdivided into two groups according to the margin width: resection margin ≤5 mm and resection margin >5 mm. We analyzed the clinicopathological findings and survival among these four groups.

RESULTS

There was no recurrence in GGO-predominant tumors after sublobar resection. Margin width did not influence the recurrence in GGO-predominant tumors. In the cases of solid-predominant tumor, 5-year recurrence-free survival after sublobar resection according to margin width ≤5 and >5 mm was 24.2 and 79.6 %, respectively (p < 0.001). Therefore, narrow margin width (resection margin ≤5 mm) was a significant risk factor for recurrence of solid-predominant tumors (hazard ratio 3.868, 95 % confidence interval 1.177-12.714, p = 0.026).

CONCLUSIONS

The width between the tumor and resection margin does not affect the recurrence after R0 sublobar resection in patients with clinical N0 GGO-predominant lung cancer ≤3 cm. By contrast, margin width is a significant risk factor for recurrence after sublobar resection in patients with clinical N0 solid-predominant lung cancer.

The prognosis of invasive adenocarcinoma presenting as ground-glass opacity on chest computed tomography after sublobar resection

Background

Ground-glass opacity (GGO) on chest computed tomography (CT) is generally associated with non-invasive or minimally invasive adenocarcinoma (MIA). However, many instances of GGO are diagnosed as invasive adenocarcinoma. The purpose of this study is to analyse the histopathologic characteristics of invasive adenocarcinoma presenting as GGO and the prognosis after sublobar resection.

Methods

We conducted a retrospective chart review of 191 patients who were treated for stage I non-small cell lung cancer presenting as a GGO-predominant tumour upon CT and who underwent curative resection. We analysed the histologic subtypes and components of invasive adenocarcinomas presenting as GGO-predominant tumours. We also compared the 5-year recurrence-free survival (RFS) of invasive adenocarcinomas presenting as GGO-predominant in patients undergoing sublobar resection or lobectomy.

Results

Of 191 GGO-predominant tumour patients, 97 patients had adenocarcinoma in situ (AIS) or MIA, and 94 patients had invasive adenocarcinoma. In the analysis of the histologic component of invasive adenocarcinoma presenting as GGO, the mean rate of the lepidic component was 47.4%, that of the acinar component was 42.1%, and that of the papillary component was 7.3%. Micropapillary and solid components were nearly absent. The 5-year RFS rates of sublobar resection and lobectomy were both 100%.

Conclusions

Invasive components such as acinar and papillary components can also be seen as GGO tumours on chest CT. After the sublobar resection of GGO-predominant tumours, a good prognosis can be expected, even if the tumour is an invasive adenocarcinoma such as the acinar or papillary subtypes.

Radiological prediction of tumor invasiveness of lung adenocarcinoma on thin-section CT

To evaluate thin-section computed tomography (CT) (TSCT) features that differentiate adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IVA), and to determine the size of solid portion on CT that correlates to pathological invasive components. Forty-eight patients were included. Nodules were classified into ground-glass nodule (GGN), part-solid, solid, and heterogeneous. Visual density of GGNs was subjectively evaluated using reference standard images: faint GGN (Ga), <-700 Hounsfield unit (HU); intermediate GGN (Gb), from -700 to -400 HU; dense GGN (Gc), >-400 HU; and mixed (Ga + Gb, Ga + Gc, and Gb + Gc). The evaluated TSCT findings included margin of nodule, distribution of solid portion, distribution of air bronchiologram, and pleural indentation. The longest diameters of the solid portion and the entire tumor were measured. Invasive diameters were measured in pathological specimens. Twenty-two AISs (16 GGNs [7 Ga, 5 Gb, 2 Gc, 1 Ga + Gc, 1 Gb + Gc], 4 part-solids, and 2 heterogeneous), 6 MIAs (1 GGN [Gb + Gc], 3 part-solids, and 2 solids), and 20 IVAs (1 GGN [Gb], 3 part-solids, and 16 solid) were found. The longest diameter (mean ± standard deviation) of the solid portion and total tumor were 9.7 ± 9.7 and 18.9 ± 5.6 mm, respectively. Significant differences in TSCT findings between AIS and IVA were margin of nodule (Pearson chi-squared test, P = 0.004), distribution of air bronchiologram (P = 0.0148), and pleural indentation (P = 0.0067). A solid portion >5.3 mm on TSCT indicated MIA or IVA, and >7.3 mm indicated IVA (receiver operating characteristic analysis, P < 0.0001). Irregular margin, air bronchiologram with disruption and/or irregular dilatation, and pleural indentation may distinguish IVA from AIS. A 5.3 to 7.3 mm solid portion on TSCT indicates MIA/IVA, and a solid portion >7.3 mm on TSCT indicates IVA.

Quantitative Computed Tomography Features for Predicting Tumor Recurrence in Patients with Surgically Resected Adenocarcinoma of the Lung

Purpose

The purpose of this study was to determine if preoperative quantitative computed tomography (CT) features including texture and histogram analysis measurements are associated with tumor recurrence in patients with surgically resected adenocarcinoma of the lung.

Methods

The study included 194 patients with surgically resected lung adenocarcinoma who underwent preoperative CT between January 2013 and December 2013. Quantitative CT feature analysis of the lung adenocarcinomas were performed using in-house software based on plug-in package for ImageJ. Ten quantitative features demonstrating the tumor size, attenuation, shape and texture were extracted. The CT parameters obtained from 1-mm and 5-mm data were compared using intraclass correlation coefficients. Univariate and multivariable logistic regression methods were used to investigate the association between tumor recurrence and preoperative CT findings.

Results

The 1-mm and 5-mm data were highly correlated in terms of diameter, perimeter, area, mean attenuation and entropy. Circularity and aspect ratio were moderately correlated. However, skewness and kurtosis were poorly correlated. Multivariable logistic regression analysis revealed that area (odds ratio [OR], 1.002 for each 1-mm² increase; P = 0.003) and mean attenuation (OR, 1.005 for each 1.0-Hounsfield unit increase; P = 0.022) were independently associated with recurrence. The receiver operating curves using these two independent predictive factors showed high diagnostic performance in predicting recurrence (C-index = 0.81, respectively).

Conclusion

Tumor area and mean attenuation are independently associated with recurrence in patients with surgically resected adenocarcinoma of the lung.

Risk factors for recurrence after sublobar resection in patients with small (2 cm or less) non-small cell lung cancer presenting as a solid-predominant tumor on chest computed tomography

BACKGROUND

Sublobar resection is considered controversial for non-small cell lung cancer (NSCLC) presenting as a solid-predominant nodule. The aim of this study was to identify risk factors related to recurrence in small-sized NSCLC presenting as a solid-predominant nodule.

METHODS

We conducted a retrospective chart review of 118 patients who were treated for clinical N0 NSCLC sized ≤2 cm and who underwent sublobar resection with clear resection margins. We assigned them to two groups according to radiologic features: ground glass opacity (GGO)-predominant tumor and solid-predominant tumor. Clinicopathological characteristics and survival were analyzed in both groups. Risk factors for recurrence were analyzed in the solid-predominant tumor group.

RESULTS

Seventy-three patients had a GGO-predominant tumor, and 45 patients had a solid-predominant tumor. Five-year recurrence-free survival (RFS) in the solid-predominant tumor and GGO-predominant tumor groups was 64.9% and 95.5%, respectively. A multivariate analysis was performed to determine factors associated with recurrence after sublobar resection in the solid-predominant tumor group; it indicated that SUVmax [hazard ratio (HR) =1.482, 95% confidence interval (CI): 1.123-1.956, P=0.005] and histologic types other than adenocarcinoma (squamous cell carcinoma, HR =8.789, 95% CI: 1.572-49.134, P=0.013; other types, HR =53.569, 95% CI: 2.616-1096.849, P=0.010) were significant risk factors for recurrence.

CONCLUSIONS

Risk factors in solid-predominant tumors sized ≤2 cm after sublobar resection are a high SUVmax and histologic types other than adenocarcinoma. Thus, lobectomy should be considered for solid-predominant NSCLC sized ≤2 cm with a high SUVmax or non-adenocarcinoma types.

Clinicopathological characteristics and prognosis of non-lepidic invasive adenocarcinoma presenting as ground glass opacity nodule

BACKGROUND

Ground glass opacity (GGO) generally associated with the lepidic component of lung adenocarcinoma. However, in some cases, GGO nodules have been associated with invasive adenocarcinomas, where a lepidic component is minimal or absent. The purpose of this study is to evaluate the clinicopathological characteristics and prognosis of non-lepidic invasive adenocarcinoma presenting as GGO nodules.

METHODS

We reviewed computed tomography (CT) images from 168 patients diagnosed with non-lepidic invasive adenocarcinoma classified as stage T1N0M0 (≤3 cm) who underwent curative anatomical resection. Tumors were classified according to radiologic features: 31 were GGO predominant (Group A) and 137 were solid predominant (Group B). The clinicopathological findings and recurrence free survival were used as outcome measures.

RESULTS

The mean percentages of micropapillary and solid component in tumor was higher in Group B than Group A (P<0.001) Pleural invasion and lymphatic invasion were more frequently seen in Group B. The presence of tumors with a micropapillary component was higher in Group B (P=0.040). The 3-year recurrence-free survival was lower in Group B than Group A (80.4% vs. 100%, P=0.019). Risk factors for recurrence such as presence of a micropapillary component and lymphatic invasion were more frequently seen in Group B.

CONCLUSIONS

Non-lepidic invasive adenocarcinoma presenting as GGO has fewer risk factors and better prognosis when compared with those presenting as solid tumors. Therefore, the presence of GGO on chest CT is a good prognostic indicator for lung cancer irrespective of histomorphologic classification.

The effectiveness of mediastinal lymph node evaluation in a patient with ground glass opacity tumor

BACKGROUND

The prognosis of non-small cell lung cancer (NSCLC) presenting as a ground glass opacity (GGO) nodule is better than other types of lung cancer. The purpose of this study was to evaluate the necessity of mediastinal lymph node evaluation (MLE) in clinical N0 GGO-predominant NSCLC.

METHODS

We conducted a retrospective chart review of 358 patients treated for clinical N0 NSCLC that was found by curative resection to be 3 cm or smaller in size. We analyzed clinicopathological findings and survival among three groups with either GGO-predominant or solid-predominant tumor: no mediastinal lymph node evaluation (NoMLE) group, mediastinal lymph node sampling (MLS) group, and mediastinal lymph node dissection (MLND) group.

RESULTS

Except for sex, there were no differences in clinicopathological characteristics among the three groups with GGO-predominant tumor or solid-predominant tumor. There was no difference in the 5-year recurrence-free survival (RFS) rate among three groups in the GGO-predominant patients (100%, 92.9%, 93.8%, respectively; P=0.889). However, in the solid-predominant tumor group, the 5-year recurrence free survival of the NoMLE group was lower than in the MLND group (48.6% vs. 73.1%, P=0.007). MLE was not a significant risk factor for recurrence in GGO-predominant tumor [hazard ratio (HR) =1.021; P=0.987]. GGO-predominant tumor [odds ratio (OR) =0.063; P=0.008] was identified as the sole parameter that significantly impacted nodal upstaging.

CONCLUSIONS

MLE is not an essential procedure for clinical N0 NSCLC presenting as a 3 cm or smaller GGO-predominant nodule.

Pure ground-glass opacity on chest computed tomography: predictive factors for invasive adenocarcinoma

BACKGROUND

Pure ground-glass opacity (GGO) on computed tomography (CT) is considered a diagnostic feature of noninvasive lung adenocarcinoma. However, pure GGO can sometimes be associated with invasive adenocarcinoma (IA). The purpose of this study was to determine the predictive factors for IA when pure GGO is present.

METHODS

Between 2011 and 2014, 83 patients with persistent pure GGO on chest CT underwent surgical treatment for lung cancer. We compared the clinical, surgical, and pathological characteristics of non-IA with those of IA.

RESULTS

A total of 66 patients (79.5%) were diagnosed with non-IA and 17 patients (20.5%) were diagnosed with IA. The mean axial diameter of the GGO lesions in IA was larger than that in non-IA (1.9 vs. 1.2 cm; P<0.001). The incidence of pleural retraction was higher in IA than in non-IA (76.5% vs. 15.2%; P<0.001). Multivariate logistic regression analysis identified GGO lesion size and the presence of pleural retraction as significant predictive factors for IA.

CONCLUSIONS

Both preoperative GGO lesion size on CT and the computed-tomography or operative finding of pleural retraction are predictive factors for IA. In patients with these findings, curative lobectomy is preferable to limited resection.

Recurrence and Survival After Segmentectomy in Patients With Prior Lung Resection for Early-Stage Non-Small Cell Lung Cancer

BACKGROUND

Lobectomy is the standard of care for patients with early-stage non-small cell lung cancer (NSCLC). However, the treatment of choice for patients with prior lung resection and a second primary NSCLC has not been established. We compared rates and patterns of recurrence and survival in patients with and without prior lung resection treated by segmentectomy and determined predictors of recurrence.

METHODS

This was a retrospective cohort study of 90 patients who underwent 91 consecutive segmentectomies for early-stage NSCLC between April 2004 and December 2014. Logistic regression was used to determine predictors of recurrence, and Kaplan-Meier curves were used to determine survival.

RESULTS

Of the 91 segmentectomies, 21 (23%) had a prior lung cancer resection and 70 (77%) were primary resections. There were 18 recurrences (20%): 9 of 21 (43%) in those with prior lung resection and 9 of 70 (13%) in those without. The 90-day mortality was 0%. The recurrence-free survival and 5-year survival were 61% and 55% in those with prior lung resection (p = 0.09) and 84% and 65% in those without (p = 0.4). Close parenchymal margin and number of lymph nodes examined were significant modifiable predictors of recurrence.

CONCLUSIONS

Segmentectomy is a reasonable option for patients with early-stage NSCLC who have had a prior lung resection. It results in similar survival but trends toward lower recurrence-free survival compared with patients undergoing primary resection.

Natural History of Pulmonary Subsolid Nodules: A Prospective Multicenter Study

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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