Evaluation of the new IASLC/ATS/ERS proposed classification of adenocarcinoma based on lepidic pattern in patients with pathological stage IA pulmonary adenocarcinoma

Utility of PET for Nodal Staging in Subsolid Clinical Stage IA (T1 N0) Lung Adenocarcinoma

Background

Positron emission tomography (PET) is the standard of care for non-small cell lung cancer (NSCLC) clinical staging, but it may have limited utility in evaluating subsolid lung adenocarcinomas that can have relatively indolent behavior without hypermetabolic activity.

Methods

The sensitivity and specificity of PET for determining pathologic lymph node status and disease-free survival were assessed in patients operated on for cT1 N0 subsolid lung adenocarcinoma from January 2006 to June 2022 (at Stanford University School of Medicine, Stanford, CA). Patients with clinical or pathologic tumor size >30 mm, hilar or mediastinal lymph node size >1cm, and purely solid tumors were excluded.

Results

PET was available in 498 of 534 (93.2%) patients and more often was used in older patients with larger and more solid tumors. The overall pathologic lymph node-positive rate was 8.4% (45 of 534). PET specificity was 95.1%, but sensitivity was only 20.0%. A tumor diameter of 18.5 mm and a solid component percentage of 62.5% had the maximum predictive accuracy for pathologic lymph node positivity, with a 0% and 1.5% rate of pathologic and PET lymph node positivity, respectively, for tumors with values lower than those thresholds. There was no significant difference in 5-year disease-free survival between individuals who did and did not undergo PET scanning (76.6% vs 96.8%; P = .07). Conversely, 134 (26.9%) patients who underwent PET scanning had 171 incidentally detected hypermetabolic lesions unrelated to lung cancer, with only 13 of 134 (9.7%) patients identified as having non-NSCLC premalignant or malignant conditions requiring further therapy.

Conclusions

PET scan use for subsolid lung adenocarcinoma has high specificity but limited sensitivity for predicting pathologic lymph node positivity. PET also has no association with disease-free survival and often detects clinically unimportant findings rather than changing lung cancer management, particularly for patients with smaller and less solid tumors.

Lepidic-Type Lung Adenocarcinomas: Is It Safe to Observe for Growth Before Treating?

BACKGROUND

Lepidic-type adenocarcinomas (LPAs) can be multifocal, and treatment is often deferred until growth is observed. This study investigated the potential downside of that strategy by evaluating the relationship of nodal involvement with tumor size and survival.

METHODS

The impact of tumor size on lymph node involvement and survival was evaluated for National Cancer Database patients who underwent surgery without induction therapy as primary treatment for cT1-3 N0 M0 histologically confirmed LPA from 2006 to 2019 by using logistic regression, Kaplan-Meier, and Cox analyses.

RESULTS

Positive nodes occurred in 442 of 8286 patients (5.3%). The incidence of having positive nodes approximately doubled with each 1-cm increment increase in size. Patients with positive nodes were more likely to have larger tumors (27 mm vs 20 mm, P < .001) and clinical ≥T2 disease (40.7% vs 26.8%, P < .001) compared with node-negative patients. However, tumor size was the only significant independent predictor of having positive nodal disease in logistic regression analysis, and this association grew stronger with each incremental centimeter increase in size. Patients with positive nodes were more likely to undergo adjuvant radiotherapy (23.5% vs 1.1%, P < .001) and chemotherapy (72.9% vs 7.9%, P < .001), and expectedly, had worse survival compared with the node-negative group in univariate (5-year overall survival, 50.9% vs 81.1%, P < .001) and multivariable (hazard ratio, 2.56; 95% CI, 2.14-3.05; P < .001) analyses.

CONCLUSIONS

Nodal involvement is relatively uncommon in early-stage LPAs but steadily increases with tumor size and is associated with dramatically worse survival. These data can be used to inform treatment decisions when evaluating LPA patients.

Selection of potential targets for stratifying congenital pulmonary airway malformation patients with molecular imaging: is MUC1 the one?

Currently there is a global lack of consensus about the best treatment for asymptomatic congenital pulmonary airway malformation (CPAM) patients. The somatic KRAS mutations commonly found in adult lung cancer combined with mucinous proliferations are sometimes found in CPAM. For this risk of developing malignancy, 70% of paediatric surgeons perform a resection for asymptomatic CPAM. In order to stratify these patients into high- and low-risk groups for developing malignancy, a minimally invasive diagnostic method is needed, for example targeted molecular imaging. A prerequisite for this technique is a cell membrane bound target. The aim of this study was to review the literature to identify potential targets for molecular imaging in CPAM patients and perform a first step to validate these findings.A systematic search was conducted to identify possible targets in CPAM and adenocarcinoma in situ (AIS) patients. The most interesting targets were evaluated with immunofluorescent staining in adjacent lung tissue, KRAS+ CPAM tissue and KRAS- CPAM tissue.In 185 included studies, 143 possible targets were described, of which 20 targets were upregulated and membrane-bound. Six of them were also upregulated in lung AIS tissue (CEACAM5, E-cadherin, EGFR, ERBB2, ITGA2 and MUC1) and as such of possible interest. Validating studies showed that MUC1 is a potential interesting target.This study provides an extensive overview of all known potential targets in CPAM that might identify those patients at risk for malignancy and conducted the first step towards validation, identifying MUC1 as the most promising target.

Challenges of the eighth edition of the American Joint Committee on Cancer staging system for pathologists focusing on early stage lung adenocarcinoma

BACKGROUND

The eighth edition of the American Joint Committee on Cancer (AJCC) staging system for lung cancer adopts new criteria for tumor size, and for determining pTis, pT1a(mi), and pT1a. The latter is based on the size of stromal invasion. It is quite challenging for lung pathologists.

METHODS

All patients who had undergone surgical resection for pulmonary adenocarcinoma (ADC) at Chung Shan Medical University Hospital between January 2014 and April 2018 were reviewed, and restaged according to the eighth AJCC staging system. The clinical characteristics and survival of patients with tumor stage 0 (pTis), I or II were analyzed.

RESULTS

In total, 376 patients were analyzed. None of the pTis, pT1a(mi), or pT1a tumors recurred during the follow-up period up to 5 years, but pT1b, pT1c, pT2a, and pT2b tumors all had a few tumor recurrences (p < 0.0001). In addition, 95.2%, 100%, and 77.5% of pTis, pT1a(mi), and pT1a tumors, respectively, had tumor sizes ≤1.0 cm by gross examination. All pTis, pT1a(mi), and pT1a tumors exhibited only lepidic, acinar, or papillary patterns histologically.

CONCLUSIONS

This study demonstrated excellent survival for lung ADC patients with pTis, pT1a(mi), and pT1a tumors when completely excised. To reduce the inconsistencies between pathologists, staging lung ADC with tumors of ≤1 cm in size grossly as pTis, pT1a(mi), or pT1a may not be necessary when the tumors exhibit only lepidic, acinar, or papillary histological patterns. A larger cohort study with sufficient follow-up data is necessary to support this proposal.

Identification and evaluation of circulating small extracellular vesicle microRNAs as diagnostic biomarkers for patients with indeterminate pulmonary nodules

Background

The identification of indeterminate pulmonary nodules (IPNs) following a low-dose computed tomography (LDCT) is a major challenge for early diagnosis of lung cancer. The inadequate assessment of IPNs’ malignancy risk results in a large number of unnecessary surgeries or an increased risk of cancer metastases. However, limited studies on non-invasive diagnosis of IPNs have been reported.

Methods

In this study, we identified and evaluated the diagnostic value of circulating small extracellular vesicle (sEV) microRNAs (miRNAs) in patients with IPNs that had been newly detected using LDCT scanning and were scheduled for surgery. Out of 459 recruited patients, 109 eligible patients with IPNs were enrolled in the training cohort (n = 47) and the test cohort (n = 62). An external cohort (n = 99) was used for validation. MiRNAs were extracted from plasma sEVs, and assessed using Small RNA sequencing. 490 lung adenocarcinoma samples and follow-up data were used to investigate the role of miRNAs in overall survival.

Results

A circulating sEV miRNA (CirsEV-miR) model was constructed from five differentially expressed miRNAs (DEMs), showing 0.920 AUC in the training cohort (n = 47), and further identified in the test cohort (n = 62) and in an external validation cohort (n = 99). Among five DEMs of the CirsEV-miR model, miR-101-3p and miR-150-5p were significantly associated with better overall survival (p = 0.0001 and p = 0.0069). The CirsEV-miR scores were calculated, which significantly correlated with IPNs diameters (p < 0.05), and were able to discriminate between benign and malignant PNs (diameter ≤ 1 cm). The expression patterns of sEV miRNAs in the benign, adenocarcinoma in situ/minimally invasive adenocarcinoma, and invasive adenocarcinoma subgroups were found to gradually change with the increase in aggressiveness for the first time. Among all DEMs of the three subgroups, five miRNAs (miR-30c-5p, miR-30e-5p, miR-500a-3p, miR-125a-5p, and miR-99a-5p) were also significantly associated with overall survival of lung adenocarcinoma patients.

Conclusions

Our results indicate that the CirsEV-miR model could help distinguish between benign and malignant PNs, providing insights into the feasibility of circulating sEV miRNAs in diagnostic biomarker development.

Trial registration: Chinese Clinical Trials: ChiCTR1800019877. Registered 05 December 2018, https://www.chictr.org.cn/showproj.aspx?proj=31346.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01366-0.

Can computed tomography differentiate adenocarcinoma in situ from minimally invasive adenocarcinoma?

BACKGROUND

Given the subtle pathological signs of adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA), effective differentiation between the two entities is crucial. However, it is difficult to predict these conditions using preoperative computed tomography (CT) imaging. In this study, we investigated whether histological diagnosis of AIS and MIA using quantitative three-dimensional CT imaging analysis could be predicted.

METHODS

We retrospectively analyzed the images and histopathological findings of patients with lung cancer who were diagnosed with AIS or MIA between January 2017 and June 2018. We used Synapse Vincent (v. 4.3) (Fujifilm) software to analyze the CT attenuation values and performed a histogram analysis.

RESULTS

There were 22 patients with AIS and 22 with MIA. The ground-glass nodule (GGN) rate was significantly higher in patients with AIS (p < 0.001), whereas the solid volume (p < 0.001) and solid rate (p = 0.001) were significantly higher in those with MIA. The mean (p = 0.002) and maximum (p = 0.025) CT values were significantly higher in patients with MIA. The 25th, 50th, 75th, and 97.5th percentiles (all p < 0.05) for the CT values were significantly higher in patients with MIA.

CONCLUSIONS

We demonstrated that quantitative analysis of 3D-CT imaging data using software can help distinguish AIS from MIA. These analyses are useful for guiding decision-making in the surgical management of early lung cancer, as well as subsequent follow-up.

Optimal method for measuring invasive size that predicts survival in invasive mucinous adenocarcinoma of the lung

PURPOSE

The purpose of this study was to determine the optimal method for measuring pathological invasive size that predicts prognosis in invasive mucinous adenocarcinoma (IMA).

METHODS

We analyzed patients who underwent complete surgical resection for lung IMA. The invasive size of IMA was measured using two methods: (1) excluding lepidic method (ELM), that is, lepidic component was excluded from the invasive area regardless of alveolar mucin and (2) including lepidic method (ILM), that is, lepidic component was included as invasive area if alveolar space was filled with mucin. The prognostic predictability of ELM and ILM on survival was assessed using univariable and multivariable Cox regression models. The discriminative power was assessed using concordance probability estimate (CPE) and Akaike's information criteria (AIC), and the prognostic impact of the newly redefined pathological stage according to ELM or ILM was also assessed.

RESULTS

A total of 101 patients were included. The median invasive size via ELM and ILM was 1.4 cm (range, 0.0-7.7 cm) and 2.1 cm (range, 0.0-14.2 cm), respectively. ELM had better discriminative power than ILM (ELM, HR = 1.38, AIC = 110.19, CPE = 0.671; ILM, HR = 1.19, AIC = 111.52, CPE = 0.655). Although the survival curves based on ILM crossed between T3 and T4, the overall survival (OS) curves based on ELM were sufficiently distinct from one another.

CONCLUSIONS

ELM has higher discriminative power for OS, and thus the optimal method for measuring the pathological invasive size of IMA should exclude the lepidic component regardless of alveolar mucin.

Clinicopathologic Features and Genetic Alterations in Adenocarcinoma In Situ and Minimally Invasive Adenocarcinoma of the Lung: Long-Term Follow-Up Study of 121 Asian Patients

BACKGROUND

Adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) are both small tumors with good prognosis after surgical resection, and most of them present as ground glass opacities (GGOs) on computed tomography (CT) screening. However, the differences in clinicopathologic features and genetic alterations between AIS and MIA are poorly elaborated, and few studies have evaluated the prognosis of MIA with different invasive components. Meanwhile, the histological features of lung lesions presenting as unchanged pure GGOs are barely understood.

METHODS

Clinicopathologic features and genetic alterations of AIS (n = 59) and MIA (n = 62) presenting as GGOs were analyzed. Long-term preoperative observation (ranging from 2 to 1967 days) and postoperative follow-up (ranging from 0 to 92 months) was conducted.

RESULTS

The tumor size and consolidation/tumor ratio were significantly larger in the MIA cohort than those in the AIS cohort both on CT and microscopy images. Immunohistochemically, the expression of p53, Ki67, and cyclin D1 was higher in MIA than in AIS. The EGFR mutation rate was significantly higher in MIA, while other genetic alterations showed no differences. Six MIA cases showed recurrence or metachronous adenocarcinoma and all the cases with a predominant micropapillary invasive pattern demonstrated this feature.

CONCLUSIONS

The current CT measurements may be helpful in distinguishing AIS from MIA, but show limited utility in predicting the histology of unchanged pure GGOs. The invasive pattern may have an influence on the postoperative process of MIA; therefore, further studies are needed to evaluate the current diagnostic criteria and treatment strategy for MIA.

[Computed tomography findings, clinicopathological features, genetic characteristics and prognosis of in situ and minimally invasive lung adenocarcinomas]

OBJECTIVE

To investigate the computed tomography findings, clinicopathological features, genetic characteristics and prognosis of in situ adenocarcinoma (AIS) and minimally invasive adenocarcinoma (MIA) of the lung.

METHODS

We retrospectively analyzed the data including computed tomography (CT) images, histopathological findings, Ki-67 immunostaining, and genetic mutations in patients with lung adenocarcinoma undergoing surgery at our hospital between 2014 and 2019.

RESULTS

Of the total of 480 patients with lung adenocarcinoma we reviewed, 73 (15.2%) had AIS (n=28) or MIA (n=45) tumors. The age of the patients with MIA was significantly younger than that of patients with AIS (P &lt; 0.02). CT scans identified pure ground-glass nodules in 46.4% of AIS cases and in 44.4% of MIA cases. Multiple GGOs were more common in MIA than in AIS cases (P &lt; 0.05), and bluured tumor margins was less frequent in AIS cases (P &lt; 0.05). No significant difference was found in EGFR mutations between MIA and AIS cases. A Ki-67 labeling index (LI) value ≥2.8% did not differentiate MIA from AIS. The follow-up time in MIA group was significantly shorter than that in AIS group, but no recurrence or death occurred.

CONCLUSIONS

Despite similar surgical outcomes and favorable survival outcomes, the patients with AIS and MIA show differences in terms of age, CT findings, EGFR mutations and Ki-67 LI.

Association between the novel classification of lung adenocarcinoma subtypes and EGFR/KRAS mutation status: A systematic literature review and pooled-data analysis

OBJECTIVES

This study aims to determine the association of EGFR/KRAS mutation status with histological subtypes of lung adenocarcinoma (LAC) based on the IASLC/ATS/ERS classification.

METHODS

Pubmed and Cochrane databases were searched from January 2011 to June 2018 for studies that included patients with LAC who underwent surgical resection were classified according to the new IASLC/ATS/ERS classification. EGFR/KRAS status assessment was requireded. The primary outcome was determined by the odds ratio (OR) of the incidence of mutation status of certain of each histological subtype. The reference group consisted of EGFR/KRAS mutation negative patients.

RESULTS

Twenty-seven eligible studies involving 9022 patients with mutation gene detection were included for analysis. Among them, 6717 (74.5%) patients were from the Asian region and, 2305 (25.5%) patients were from Non-Asian regions. The most prevalent subtype was acinar (34.7%), followed by papillary (22.9%), lepidic (18.9%), solid (13.6%), micropapillary (6.3%), and invasive mucinous adenocarcinoma (3.5%). EGFR mutations were more common in patients with resected lepidic predominant adenocarcinoma (OR,1.76; 95%CI, 1.38-2.24;p < 0.01) and were rarely found in solid predominant adenocarcinoma (OR,0.28; 95%CI, 0.23-0.34;p < 0.01) or IMA (OR,0.10; 95%CI, 0.06-0.14;p < 0.01). Conversely, KRAS mutations were characterized by IMA (OR,7.01; 95%CI, 5.11-9.62;p < 0.01), and were less frequently identified in lepidic (OR,0.58; 95%CI, 0.45-0.75;p < 0.01) and acinar (OR,0.65; 95%CI, 0.55-0.78;p < 0.01) predominant subtypes. Further analyses were performed in Asian and Non-Asian groups and the results were consistent.

CONCLUSIONS

The current study confirms that the IASLC/ATS/ERS classification is associated with driver gene alterations in resected LAC.

Should minimally invasive lung adenocarcinoma be transferred from stage IA1 to stage 0 in future updates of the TNM staging system?

Background

The 8th International Association Study of Lung Cancer (IASLC) TNM classification staging project for lung cancer has classified patients with adenocarcinoma in situ (AIS) into stage 0, while patients with a minimally invasive adenocarcinoma (MIA) were classified into stage IA1. However, MIA patients, similar to AIS patients, have an approximately a 100% 5-year survival. This study aimed to investigate if MIA could be transferred from stage IA to stage 0 in the next TNM staging system.

Methods

We retrospectively reviewed 1,524 consecutive patients with a pathologically confirmed AIS, MIA and an invasive adenocarcinoma (IADC) in stage IA1. Disease-free survival (DFS) and overall survival (OS) were analyzed to evaluate survival difference between these three groups.

Results

There were 412 AIS, 675 MIA and 437 IADC patients in stage IA1. No statistically significant differences for DFS and OS (P=0.109) were seen between the AIS and MIA groups. Patients of the IADC group had significantly worse DFS (P=0.003) but the OS rate (P=0.941) was insignificant when compared with the MIA patients. Similar survival results were seen when comparisons were made between the IADC and AIS/MIA groups. The IADC group had a worse DFS (P=0.001) rate but no OS (P=0.380) difference with the AIS/MIA groups.

Conclusions

Patients with AIS and MIA had similar post-surgical survival rates. We propose that MIA may potentially be transferred from IA1 to stage 0 in the future.

Second predominant subtype predicts outcomes of intermediate-malignant invasive lung adenocarcinoma†

OBJECTIVES

Acinar predominant and papillary predominant invasive adenocarcinomas are likely to be classified as intermediate-malignant types. Although these two types of adenocarcinoma are distinguished morphologically, the differences between their malignant behaviours and prognoses are not clear. The aim of this study is to provide a prognostically relevant stratification of these similar subtypes based on pathological features.

METHODS

We retrospectively reviewed 347 consecutive clinically N0M0 lung adenocarcinomas of ≤3 cm in diameter that were resected between April 2006 and December 2010 at two institutes. Acinar and papillary predominant adenocarcinomas were classified into acinar/papillary-lepidic type and acinar/papillary-non-lepidic type according to whether the second predominant component was a lepidic or invasive component.

RESULTS

Fifty-four acinar and 59 papillary predominant adenocarcinoma cases were classified as acinar/papillary-lepidic type (n = 65) or acinar/papillary-non-lepidic type (n = 48) cases. Acinar/papillary-non-lepidic type cases were accompanied by more vascular invasion (13.8% vs 31.3%, P = 0.0451) and pleural invasion (9.2% vs 25.0%, P = 0.0450) than were acinar/papillary-lepidic type cases. Five-year overall survival (OS) and recurrence-free survival (RFS) also differed significantly between these types (5-year OS: acinar/papillary-lepidic type, 96.3% vs acinar/papillary-non-lepidic type, 61.8%, hazard ratio = 6.315, P = 0.00650; 5-year RFS: acinar/papillary-lepidic type, 91.4% vs acinar/papillary-non-lepidic type, 68.8%, hazard ratio = 2.967, P = 0.0210). Multivariate analysis revealed that a second predominant component was an independent prognostic factor for RFS (acinar/papillary-non-lepidic type: hazard ratio = 3.784, 95% confidence interval 1.091–13.128, P = 0.036).

CONCLUSIONS

The pathological second predominant component allows intermediate-malignant adenocarcinomas to be subclassified with prognostic significance. It can be utilized when assessing postoperative risks for recurrence and when considering therapeutic strategies.

The Role of Extent of Surgical Resection and Lymph Node Assessment for Clinical Stage I Pulmonary Lepidic Adenocarcinoma: An Analysis of 1991 Patients

BACKGROUND

This study examined the association of extent of lung resection, pathologic nodal evaluation, and survival for patients with clinical stage I (cT1-2N0M0) adenocarcinoma with lepidic histologic features in the National Cancer Data Base.

METHODS

The association between extent of surgical resection and long-term survival for patients in the National Cancer Data Base with clinical stage I lepidic adenocarcinoma who underwent lobectomy or sublobar resection was evaluated using Kaplan-Meier and Cox proportional hazards regression analyses.

RESULTS

Of the 1991 patients with cT1-2N0M0 lepidic adenocarcinoma who met the study criteria, 1544 underwent lobectomy and 447 underwent sublobar resection. Patients treated with sublobar resection were older, more likely to be female, and had higher Charlson/Deyo comorbidity scores, but they had smaller tumors and lower T status. Of the patients treated with lobectomy, 6% (n = 92) were upstaged because of positive nodal disease, with a median of seven lymph nodes sampled (interquartile range 4-10). In an analysis of the entire cohort, lobectomy was associated with a significant survival advantage over sublobar resection in univariate analysis (median survival 9.2 versus 7.5 years, p = 0.022, 5-year survival 70.5% versus 67.8%) and after multivariable adjustment (hazard ratio = 0.81, 95% confidence interval: 0.68-0.95, p = 0.011). However, lobectomy was no longer independently associated with improved survival when compared with sublobar resection (hazard ratio = 0.99, 95% confidence interval: 0.77-1.27, p = 0.905) in a multivariable analysis of a subset of patients in which only those patients who had undergone a sublobar resection including lymph node sampling were compared with patients treated with lobectomy.

CONCLUSIONS

Surgeons treating patients with stage I lung adenocarcinoma with lepidic features should cautiously utilize sublobar resection rather than lobectomy, and they must always perform adequate pathologic lymph node evaluation.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Lobectomy and limited resection in small-sized peripheral non-small cell lung cancer

BACKGROUND

Although lobectomy is the standard surgical procedure for non-small cell lung cancer (NSCLC), recent studies show favorable outcomes after limited resection in patients with small-sized peripheral tumors. We conducted a randomized controlled trial of such patients to estimate postoperative outcomes and pulmonary function following these surgical techniques.

METHODS

Between 2005 and 2008, eligible patients with tumors of 2 cm or less were randomly assigned 1:1 to undergo lobectomy or limited resection; 32 and 33 NSCLC patients in each group, respectively, were analyzed. The primary end points were 5-year overall survival (OS) and disease-free survival (DFS), while the secondary end points were postoperative pulmonary function including forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁).

RESULTS

The 5-year OS rates were 93.8% and 90.9% in the lobectomy and limited resection groups, respectively (P=0.921). The 5-year DFS rates were 93.8% and 90.9% in the lobectomy and limited resection groups, respectively (P=0.714). These rates did not differ significantly between the two resection groups. The median postoperative/preoperative FVC ratios were 84.1% and 90.0% in the lobectomy and limited resection groups, respectively, while the median postoperative/preoperative FEV₁ ratios were 81.9% and 89.1%, respectively. Both ratios were significantly higher in the limited resection group (P=0.032 and P=0.005 for FVC and FEV₁ ratios, respectively).

CONCLUSIONS

A similar outcome, with more preserved postoperative pulmonary function, was observed in patients who underwent limited resection compared to those who underwent lobectomy. Ongoing large-scale multi-institutional prospective randomized trials of lobar versus sublobar resection in patients with small peripheral NSCLCs will hopefully provide definitive information about intentional limited resection of small peripheral tumors.

The IASLC Lung Cancer Staging Project: Proposals for Coding T Categories for Subsolid Nodules and Assessment of Tumor Size in Part-Solid Tumors in the Forthcoming Eighth Edition of the TNM Classification of Lung Cancer

This article proposes codes for the primary tumor categories of adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) and a uniform way to measure tumor size in part-solid tumors for the eighth edition of the tumor, node, and metastasis classification of lung cancer. In 2011, new entities of AIS, MIA, and lepidic predominant adenocarcinoma were defined, and they were later incorporated into the 2015 World Health Organization classification of lung cancer. To fit these entities into the T component of the staging system, the Tis category is proposed for AIS, with Tis (AIS) specified if it is to be distinguished from squamous cell carcinoma in situ (SCIS), which is to be designated Tis (SCIS). We also propose that MIA be classified as T1mi. Furthermore, the use of the invasive size for T descriptor size follows a recommendation made in three editions of the Union for International Cancer Control tumor, node, and metastasis supplement since 2003. For tumor size, the greatest dimension should be reported both clinically and pathologically. In nonmucinous lung adenocarcinomas, the computed tomography (CT) findings of ground glass versus solid opacities tend to correspond respectively to lepidic versus invasive patterns seen pathologically. However, this correlation is not absolute; so when CT features suggest nonmucinous AIS, MIA, and lepidic predominant adenocarcinoma, the suspected diagnosis and clinical staging should be regarded as a preliminary assessment that is subject to revision after pathologic evaluation of resected specimens. The ability to predict invasive versus noninvasive size on the basis of solid versus ground glass components is not applicable to mucinous AIS, MIA, or invasive mucinous adenocarcinomas because they generally show solid nodules or consolidation on CT.

Primary adenocarcinoma of the lung--histological subtypes and outcome after surgery, using the IASLC/ATS/ERS classification of lung adenocarcinoma

Adenocarcinoma is the most common histological type of lung carcinoma. Recently the histologic classification of adenocarcinomas in the lung was modified to better reflect biologic properties and prognosis. We reviewed the histology of all primary lung adenocarcinomas operated on in Iceland during a 20-year period and assessed the impact of histology on survival. This nationwide study included 285 patients (mean age 67 years, 57% female), who underwent resection in Iceland from 1991 to 2010. Tumors were reclassified according to the current IASLC/ATS/ERS classification system. Overall survival was estimated by the Kaplan-Meier method and Cox regression analysis used to evaluate prognostic factors of overall mortality. Acinar predominant adenocarcinoma was the most common histological subtype (46%) followed by solid-predominant (SPA) with mucin production comprised (23%). Non-invasive carcinomas were rare. A difference in survival between the histological adenocarcinoma subtypes was not seen (p = 0.32) and multivariate analysis showed that advanced stage and age predicted worse outcome, but histologic subtyping of adenocarcinoma did not. In this nation-wide study there was not a statistical difference in survival according to adenocarcinoma subtypes and the histological subtype did not predict mortality. Preinvasive and minimally invasive adenocarcinomas were rare.

Application of Lepidic Component Predominance to Adjuvant Chemotherapy with Oral Fluoropyrimidines for Stage I Lung Adenocarcinoma

BACKGROUND

In the present study we aimed to investigate whether the predominance of the lepidic component in tumors was associated with the outcome of postoperative adjuvant chemotherapy for stage I lung adenocarcinoma.

PATIENTS AND METHODS

Charts for patients with pathological stage I lung adenocarcinoma were retrospectively reviewed and then outcomes of adjuvant chemotherapy were assessed according to the lepidic component predominance in tumors. Prognostic factors were evaluated using a Cox proportional hazard model. Propensity scores were determined using the optimal matching method on the basis of Cox modeling and matched (1:1) analysis was applied after classification into lepidic and nonlepidic predominant tumors.

RESULTS

Among 798 patients with stage I lung adenocarcinoma, 168 received adjuvant chemotherapy. Although adjuvant chemotherapy conferred no disease-free survival (DFS) advantage upon patients with lepidic predominant tumors, it improved DFS in T1b and T2a nonlepidic predominant tumors (P = .045 and P = .029, respectively). Propensity score matched analysis revealed no survival benefits of adjuvant oral fluoropyrimidines in lepidic predominant tumors (DFS, P = .461 and overall survival, P = .983) and the positive survival advantages in nonlepidic predominant tumors (DFS, P = .015 and overall survival, P = .027).

CONCLUSION

Adjuvant oral fluoropyrimidines conferred a better survival advantage upon patients with nonlepidic predominant tumors than patients with lepidic predominant tumors. The predominance of a lepidic component could serve as an indicator of adjuvant chemotherapy with oral fluoropyrimidines in stage I lung adenocarcinoma.

Association between epithelial-mesenchymal transition and cancer stemness and their effect on the prognosis of lung adenocarcinoma

The epithelial-mesenchymal transition (EMT) and cancer stemness (CS) are reported to be pivotal phenomena involved in metastasis, recurrence, and drug-resistance in lung cancer; however, their effects on tumor malignancy in clinical settings are not completely understood. The mutual association between these factors also remains elusive and are worthy of investigation. The purpose of this study was to elucidate the association between EMT and CS, and their effect on the prognosis of patients with lung adenocarcinoma. A total of 239 lung adenocarcinoma specimens were collected from patients who had undergone surgery at Kyoto University Hospital from January 2001 to December 2007. Both EMT (E-cadherin,vimentin) and CS (CD133, CD44, aldehyde dehydrogenase) markers were analyzed through immunostaining of tumor specimens. The association between EMT and CS as well as the patients' clinical information was integrated and statistically analyzed. The molecular expression of E-cadherin, vimentin, and CD133 were significantly correlated with prognosis (P = 0.003, P = 0.005, and P < 0.001). A negative correlation was found between E-cadherin and vimentin expression (P < 0.001), whereas, a positive correlation was found between vimentin and CD133 expression (P = 0.020). CD133 was a stronger prognostic factor than an EMT marker. Elevated CD133 expression is the signature marker of EMT and CS association in lung adenocarcinoma. EMT and CS are associated in lung adenocarcinoma. Importantly, CD133 is suggested to be the key factor that links EMT and CS, thereby exacerbating tumor progression.

Impact of Lepidic Component Occupancy on Effects of Adjuvant Chemotherapy for Lung Adenocarcinoma

BACKGROUND

The prognosis of lepidic predominant lung adenocarcinoma is favorable. We postulated that lepidic predominant tumors might not require postoperative adjuvant chemotherapy. The present study aims to determine whether lepidic component occupancy affects overall survival after postoperative adjuvant chemotherapy for lung adenocarcinoma.

METHODS

Clinical and pathologic data were collected from a database and from the medical records of 964 patients with completely resected lung adenocarcinoma. We assessed the influence of lepidic component occupancy in the tumor on the outcomes of adjuvant chemotherapy.

RESULTS

Among the patients, 270 received adjuvant chemotherapy and 694 did not, and 415 and 549 had lepidic predominant and non-lepidic predominant tumors, respectively. Adjuvant chemotherapy contributed to better overall survival compared with observation in non-lepidic predominant tumors (p = 0.025). Multivariate analyses revealed age, sex, stage, lepidic component occupancy, and adjuvant chemotherapy as independent prognostic factors for overall survival. The overall survival was significantly longer for patients with non-lepidic predominant tumors at stages IA, IB, and II-III under adjuvant chemotherapy compared with observation (p = 0.040, p = 0.007, and p = 0.012, respectively), whereas survival rates were similar for patients with all stages of lepidic predominant tumors even after propensity score matching study.

CONCLUSIONS

Lepidic component occupancy reflected the effect of adjuvant chemotherapy for lung adenocarcinoma. Adjuvant chemotherapy did not have much impact for lepidic predominant tumors and could be considered for non-lepidic predominant tumors even at stage IA.