Visceral pleural invasion in lung cancer: recognizing histologic parameters that impact staging and prognosis

Diagnosis, treatment, and prognosis of stage IB non-small cell lung cancer with visceral pleural invasion

With the increasing implementation of early lung cancer screening and the increasing emphasis on physical examinations, the early-stage lung cancer detection rate continues to rise. Visceral pleural invasion (VPI), which denotes the tumor's breach of the elastic layer or reaching the surface of the visceral pleura, stands as a pivotal factor that impacts the prognosis of patients with non-small cell lung cancer (NSCLC) and directly influences the pathological staging of early-stage cases. According to the latest 9th edition of the TNM staging system for NSCLC, even when the tumor diameter is less than 3 cm, the final T stage remains T2a if VPI is present. There is considerable controversy within the guidelines regarding treatment options for stage IB NSCLC, especially among patients exhibiting VPI. Moreover, the precise determination of VPI is important in guiding treatment selection and prognostic evaluation in individuals with NSCLC. This article aims to provide a comprehensive review of the current status and advancements in studies pertaining to stage IB NSCLC accompanied by VPI.

Development and validation of 18F-FDG PET/CT radiomics-based nomogram to predict visceral pleural invasion in solid lung adenocarcinoma

OBJECTIVES

This study aimed to establish a radiomics model based on 18F-FDG PET/CT images to predict visceral pleural invasion (VPI) of solid lung adenocarcinoma preoperatively.

METHODS

We retrospectively enrolled 165 solid lung adenocarcinoma patients confirmed by histopathology with 18F-FDG PET/CT images. Patients were divided into training and validation at a ratio of 0.7. To find significant VPI predictors, we collected clinicopathological information and metabolic parameters measured from PET/CT images. Three-dimensional (3D) radiomics features were extracted from each PET and CT volume of interest (VOI). Receiver operating characteristic (ROC) curve was performed to determine the performance of the model. Accuracy, sensitivity, specificity and area under curve (AUC) were calculated. Finally, their performance was evaluated by concordance index (C-index) and decision curve analysis (DCA) in training and validation cohorts.

RESULTS

165 patients were divided into training cohort (n = 116) and validation cohort (n = 49). Multivariate analysis showed that histology grade, maximum standardized uptake value (SUVmax), distance from the lesion to the pleura (DLP) and the radiomics features had statistically significant differences between patients with and without VPI (P < 0.05). A nomogram was developed based on the logistic regression method. The accuracy of ROC curve analysis of this model was 75.86% in the training cohort (AUC: 0.867; C-index: 0.867; sensitivity: 0.694; specificity: 0.889) and the accuracy rate in validation cohort was 71.55% (AUC: 0.889; C-index: 0.819; sensitivity: 0.654; specificity: 0.739).

CONCLUSIONS

A PET/CT-based radiomics model was developed with SUVmax, histology grade, DLP, and radiomics features. It can be easily used for individualized VPI prediction.

Peripheral lung adenocarcinomas harboring epithelial growth factor receptor mutations with microRNA-135b overexpression are more likely to invade visceral pleura

Lung adenocarcinoma, characterized by its early and aggressive local invasion and high metastatic potential, is the most frequently observed histological type of non-small-cell lung cancer (NSCLC). Visceral pleural invasion (VPI) caused by peripheral lung adenocarcinomas is closely associated with the poor prognosis of patients with NSCLC. The association between VPI and some clinicopathological characteristics has been observed in the past few decades. However, the molecular mechanism of VPI in lung adenocarcinomas is unknown. In the present, the expression level of microRNA (miR-)135b and epidermal growth factor receptor (EGFR) mutations using the reverse transcription-quantitative polymerase chain reaction and DNA sequencing, respectively. In addition, the present study aimed at exploring the association between the miR-135b level, EGFR mutations and VPI in peripheral lung adenocarcinoma. The results of the present study demonstrated that miR-135b was significantly upregulated in lung adenocarcinoma compared with adjacent normal tissue and positively associated EGFR mutations in peripheral lung adenocarcinoma. Furthermore, it was identified that lung adenocarcinomas with EGFR mutations and miR-135b overexpression were more likely to invade visceral pleura. Taken together, these findings indicate that miR-135b overexpression is positively associated with mutations to EGFR, which may promote the development of peripheral lung adenocarcinomas by the formation of VPI. This indicates that the two factors may serve as prognostic markers and molecular targets for the treatment of peripheral lung adenocarcinomas.

Visceral pleural invasion is not a significant prognostic factor in patients with a part-solid lung cancer

BACKGROUND

Visceral pleural invasion (VPI) has been considered to be a prognostic factor. If a tumor shows VPI, it increases the T descriptor and upstages a tumor from stage IA to stage IB pathologically, even for those less than 30 mm in diameter. However, there is still some controversy regarding the prognostic significance of VPI in patients with radiologically early lung cancer with ground glass opacity.

METHODS

Between 2004 and 2012, 466 patients with surgically resected pathologic N0 non-small cell lung cancer less than 30 mm in diameter who showed a "part-solid" or "pure-solid" appearance on thin-section computed tomography scan were retrospectively reviewed. A Cox proportional hazard model was used to evaluate prognostic factors. Survival was calculated by the Kaplan-Meier method.

RESULTS

Two hundred thirty-seven patients (55%) showed part-solid and 209 (45%) showed pure-solid nodules on thin-section computed tomography scan. VPI was found in 24 (10%) part-solid nodules and 79 (38%) pure-solid nodules. On the basis of a multivariate analysis, VPI was not a significant prognostic factor in patients with part-solid nodules (p=0.5902). In this group, the 5-year survival rates in patients with and without VPI were 85.6% and 94.9%, respectively (p=0.3798). By contrast, VPI, vessel invasion, maximum tumor diameter, and carcinoembryonic antigen level were significant prognostic factors in patients with pure-solid nodules (p=0.0211, 0.0188, 0.0372, and 0.0492, respectively). Moreover, the 5-year survival in patients with VPI (70.1%) was significantly worse than that in patients without VPI (81.3%) among patients with pure-solid nodules (p=0.0051).

CONCLUSIONS

VPI may not contribute to the prognosis of patients with part-solid nodules. Thus, upgrading of the TNM stage on the basis of VPI should be carefully considered in these patients.

Are elastic stain and specialty sign out necessary to evaluate pleural invasion in lung cancers?

The seventh edition of American Joint Committee on Cancer (AJCC) staging system assigns lung cancers with visceral pleural invasion in the tumor size of 3 cm or less than 3 cm as T2 and without pleural invasion as T1. However, it may be difficult to distinguish with certainty between PL0 (no pleural invasion) and PL1 (extends through the elastic layer) on routine hematoxylin and eosin (H&E) stain. In this study, 25 cases of peripherally located lung adenocarcinoma were retrieved from the surgical pathology archives at the Asan Medical Center from May through June 2009. One representative H&E-stained slide was selected from each case and circulated to 31 pathology trainees and board-certified pathologists at Asan Medical Center who evaluated presence or absence of pleural invasion on H&E-stained slides. Elastic stain was used to determine the final status of pleural invasion for each case. The concordance rate of all pathologists with elastic stain results was, overall, 60.5%. The concordance rate of 2 lung specialists was 64%, better than the remaining faculty (54.7%). Fellows' and residents' evaluations were slightly more concordant than those of faculty responses (faculty overall, 56.4%; fellows, 62%; residents, 63.6%), but this difference was not statistically significant (P = .228). Our results confirm that pleural invasion status is difficult to discern with certainty on H&E-stained sections alone. Therefore, we recommend the routine use of elastic stain in evaluation of pleural invasion in all peripherally located lung cancers. Furthermore, our study indicates that subspecialty sign out may be preferable in evaluation of pleural invasion status.

A histochemical approach to the diagnosis of visceral pleural infiltration by non-small cell lung cancer

INTRODUCTION

Although invasion of the visceral pleura (VPI) by non-small cell lung cancer (NSCLC) is a TNM-relevant diagnostic criterion and is known to affect the patients' prognoses, until recently there were no standardized or internationally accepted guidelines. This resulted in a diagnostic ambiguity leading to different tumor staging systems and to hardly comparable patient collectives in research studies world wide. The major problem in this issue is to exactly define what constitutes for the diagnosis of VPI with respect to anatomical landmarks.

METHODS

In order to address this problem we investigated the pleural infiltration depth of 173 NSCLC specimens without lymph node metastases and proven tumor-related death using elastic stains and a scoring system referring to prominent pleural elastic layers, the lamina elastica externa and interna, as anatomical landmarks.

RESULTS

Performing comparative Kaplan-Meier survival analyses for each patient collective we could not find any significant difference in the patients' survival. This indicates that a differential evaluation of the tumor infiltration depth according to the elastic layers is not practicable.

CONCLUSIONS

Our findings support the consequent application of the recently proposed, pragmatic approach of the international staging committee for lung cancer (IASLC) to define an internationally accepted and standardized staging system for VPI.

Lung Carcinoma Staging Problems

The tumor-node-metastasis (TNM) system is the most commonly used staging system for cancers, including lung cancer. The TNM descriptors and the stage groupings reflect differences in patient prognosis and choices for specific therapies. Generally, the higher the T, N, or M, and the higher the stage grouping, the worse the prognosis is for patients in that category. TNM stage is traditionally the most important factor predicting survival of lung cancer patients.

An update on lung cancer staging

The staging committee of the International Association for the Study of Lung Cancer has recently published, in collaboration with the International Union Against Cancer and the American Joint Committee on Cancer, the recommendations for the upcoming 7th edition of the tumor, node, metastasis classification and staging manual. This article reviews the changes in criteria for the tumor, node, metastasis components and discusses the issues that will be faced by pathologists when examining lung cancer specimens, including recommendations for tumor measurement, differentiation of multiple primary tumors versus metastases, and visceral pleural invasion.

Value of elastin staining in the assessment of peritoneal implants associated with ovarian serous borderline tumours

AIMS

To determine whether elastin stains aid in classifying peritoneal implants associated with ovarian serous borderline tumours (SBT).

METHODS AND RESULTS

The study group comprised 80 implants (nine invasive and 71 non-invasive) from 28 patients with ovarian SBT. Elastin stains were performed using histochemical and immunohistochemical methods to demonstrate the peritoneal elastic lamina (PEL), and evaluated with regard to assessment of the subtype of implant. The elastin stains demonstrated the PEL in most anatomical sites other than the omentum and the bladder and were considered helpful in 44/80 (55%) cases. The stains were most useful in the assessment of poorly oriented or traumatized biopsy specimens and in confirming the superficial distribution of non-invasive implants. The staining was non-contributory in most of the remaining biopsies, because the PEL was not identified.

CONCLUSIONS

Demonstration of the PEL using elastin stains can be useful in the subclassification of implants associated with ovarian SBT and is of most value in confirming the superficial distribution of non-invasive lesions. However, evaluation is limited by the absence of a defined elastic layer in a proportion of biopsy specimens, possibly reflecting their superficial location, as well as absence of a distinct PEL in sites such as the omentum.

Commonly encountered difficulties in pathologic staging of lung cancer

CONTEXT

Lung cancer is the leading cause of cancer mortality worldwide. Despite technological, therapeutic, and scientific advances, most patients present with incurable disease and a poor chance of long-term survival. For those with potentially curable disease, lung cancer staging greatly influences therapeutic decisions. Therefore, surgical pathologists determine many facets of lung cancer patient care.

OBJECTIVE

To present the current lung cancer staging system and examine the importance of mediastinal lymph node sampling, and also to discuss particularly confusing and/or challenging areas in lung cancer staging, including assessment of visceral pleura invasion, bronchial and carinal involvement, and the staging of synchronous carcinomas.

DATA SOURCES

Published current and prior staging manuals from the American Joint Committee on Cancer and the International Union Against Cancer as well as selected articles pertaining to lung cancer staging and diagnosis accessible through PubMed (National Library of Medicine) form the basis of this review.

CONCLUSIONS

Proper lung cancer staging requires more than a superficial appreciation of the staging system. Clinically relevant specimen gross examination and histologic review depend on a thorough understanding of the staging guidelines. Common sense is also required when one is confronted with a tumor specimen that defies easy assignment to the TNM staging system.

Impact of Elastic Staining on the Staging of Peripheral Lung Cancers

Accurate staging of lung cancer has a profound impact on patient management. For stage I nonsmall cell lung carcinomas (NSCLCs), the absence (stage IA) or presence (stage IB) of visceral pleural invasion represents a critical therapeutic branch point: patients with stage IB NSCLC benefit from adjuvant chemotherapy, whereas patients with stage IA NSCLC do not. Elastic staining has been advocated as a simple method for visualizing pleural invasion. The purpose of this study was to determine whether routine elastic staining of the resected peripheral NSCLCs alters tumor staging in a meaningful way. The study cases consisted of 100 consecutive peripheral NSCLCs resections that were pathologically staged as IA based on routine histologic assessment. Each case was stained with the Movats pentachrome elastic stain to aid identification of visceral pleural invasion. To assess current standards of surgical pathology practice, members of the American Association of Directors of Anatomic and Surgical Pathology were asked whether they never, sometimes, or always order elastic stains for peripheral NSCLCs that abut the pleura. Elastic staining resulted in a change of tumor stage from IA to IB in 19 (19%) cases. Of the 49 pathologists that responded to the survey, 25 (51%) never, 14 (29%) sometimes, and 10 (20%) always order an elastic stain for NSCLCs abutting the pleura. Elastic staining is currently not standard surgical pathology practice for the evaluation of peripheral NSCLCs, but it should be. Invasion of the pleura is an elusive finding that is best appreciated with an elastic stain. Our experience suggests that routine elastic tissue staining should be performed as a standard method of assessing pleural involvement for pleural-based nonsmall cell lung carcinomas.

Differential CT features of infectious pneumonia versus bronchioloalveolar carcinoma (BAC) mimicking pneumonia

The purpose of this study was to evaluate retrospectively the differential CT features of bronchioloalveolar carcinoma (BAC) mimicking pneumonia and infectious pneumonia at the lung periphery. CT images were reviewed in 47 patients with focal areas of parenchymal opacification at the lung periphery. We evaluated the presence of ground-glass attenuation, marginal conspicuity of the lesion, CT angiogram sign, air-bronchogram sign, a bubble-like low-attenuation area within the lesion, presence of pleural thickening and retraction associated with the lesion, presence of pleural effusion and extra-pleural fatty hypertrophy, presence of bronchial wall thickening proximal to the lesion, and air-trapping in the normal lung near the lesion. BAC (n=18) depicted the presence of a bubble-like low-attenuation area within the lesion, whereas infectious pneumonia (n=29) represented the pleural thickening associated with the lesion and bronchial wall thickening proximal to the lesion (P<0.05). The other CT findings showed no significant differences (P>0.05). The focal areas of the parenchymal opacification on the CT images may suggest infectious pneumonia rather than BAC when they show bronchial wall thickening proximal to the lesion and pleural thickening associated with the lesion, whereas BAC is characterized as the presence of a bubble-like low attenuation area within the tumor.