Efficacy of Preoperative Biopsy in Predicting the Newly Proposed Histologic Grade of Resected Lung Adenocarcinoma.

A novel histologic grading system for invasive lung adenocarcinomas (LUAD) has been newly proposed and adopted by the World Health Organization (WHO) classification. We aimed to evaluate the concordance of newly established grades between preoperative biopsy and surgically resected LUAD samples. Additionally, factors affecting the concordance rate and its prognostic impact were also analyzed. In this study, surgically resected specimens of 222 patients with invasive LUAD and their preoperative biopsies collected between January 2013 and December 2020 were used. We determined the histologic subtypes of preoperative biopsy and surgically resected specimens and classified them separately according to the novel WHO grading system. The overall concordance rate of the novel WHO grades between preoperative biopsy and surgically resected samples was 81.5%, which was higher than that of the predominant subtype. When stratified by grades, the concordance rate of grades 1 (well-differentiated, 84.2%) and 3 (poorly differentiated, 89.1%) was found to be superior compared to grade 2 (moderately differentiated, 66.2%). Overall, the concordance rate was not significantly different from biopsy characteristics, including the number of biopsy samples, biopsy sample size, and tumor area size. On the other hand, the concordance rate of grades 1 and 2 was significantly higher in tumors with smaller invasive diameters, and that of grade 3 was significantly higher in tumors with larger invasive diameters. Preoperative biopsy specimens can predict the novel WHO grades, especially grades 1 and 3 of surgically resected specimens, more accurately than the former grading system, regardless of preoperative biopsy or clinicopathologic characteristics.

Prognostic significance of vascular invasion in intermediate-grade subtype of lung adenocarcinoma.

OBJECTIVES: Although the recent reclassification of histological subtypes of lung adenocarcinoma reflects disease prognosis better, the prognosis of papillary and acinar-predominant adenocarcinoma, which are highly prevalent, is heterogeneity. The present study aimed to identify the prognostic indicators for papillary and acinar-predominant adenocarcinoma. METHODS: This retrospective study included 315 consecutive patients with completely resected pathological N0 lung adenocarcinoma tumors ≤3 cm from two institutions. Tumors were classified according to histologically predominant subtypes as low-grade (adenocarcinoma in situ, minimally invasive adenocarcinoma or lepidic predominant), intermediate-grade (papillary or acinar predominant) or high-grade (solid or micropapillary predominant). Prognostic factors in intermediate-grade group were assessed among clinicopathological factors of age, gender, surgical procedure, tumor size, pleural, lymphatic and vascular invasion using Cox proportion hazards analyses. RESULTS: There were 174 patients in the low-grade group, 109 in the intermediate-grade group and 32 in the high-grade group. The 3-year recurrence-free survival rates were 98.1%, 86.3% and 74.8% for these groups, respectively (P < 0.001). In the intermediate-grade group, the presence of vascular invasion was an independent prognostic factor on multivariate Cox regression analysis of recurrence-free survival (hazard ratio, 3.48; 95% confidence interval, 1.26-9.57, P = 0.01). Classification of intermediate-grade group based on vascular invasion revealed a clear division into favorable and unfavorable prognostic subgroups. CONCLUSIONS: Consideration of the vascular invasion status in addition to the predominant subtype could provide a more accurate assessment of malignant aggressiveness and prognosis of patients with early-stage lung adenocarcinoma.

[New WHO classification of lung adenocarcinoma and preneoplasia]. / Nouvelle classification OMS 2015 des adénocarcinomes pulmonaires et prénéoplasies.

The 2015 WHO classification of tumors of the lung, pleura, thymus and heart has just been published with numerous important changes from the 2004 WHO classification. The most significant changes involve (1) use of immunohistochemistry throughout the classification, (2) integration of molecular testing for personalized strategies for advanced lung cancer patients, (3) a new classification for small biopsies and cytology, (4) a new classification of lung adenocarcinoma as proposed by the 2011 IASLC/ATS/ERS, (5) restriction of the diagnosis of large cell carcinoma only to resected tumors that lack any clear morphologic or immunohistochemical differentiation. Regarding adenocarcinoma, the terms bronchioloalveolar carcinoma (BAC) and mixed subtype adenocarcinoma have been suppressed and replaced for the former by the term adenocarcinoma in situ (AIS) as a preinvasive lesion to join atypical adenomatous hyperplasia (AAH). A new category has been defined, the minimally invasive adenocarcinoma (MIA), and invasive adenocarcinomas are now classified according to the predominant subtype after subtyping by semi-quantitatively percentage of various subtypes present in 5% increments. The term "lepidic" is restricted to a non-invasive component (previously classified as BAC) present as part of an invasive adenocarcinoma. "Invasive mucinous adenocarcinoma" is used for formerly adenocarcinomas classified as mucinous BAC, excluding tumors that meet criteria for AIS or MIA. The subtypes of clear cell and signet ring adenocarcinoma are discontinued, as well the term of mucinous cystadenocarcinoma, included in the category of colloid adenocarcinoma. Thus new classification of lung adenocarcinoma is sustained by genetics and has clinical impact for therapeutic strategies.

Prognostic value of predominant subtype in pathological stage II-III lung adenocarcinoma with epidermal growth factor receptor mutation.

OBJECTIVES: This study extracted clinicopathological features associated with recurrence and evaluated the tumor microenvironment in consecutive cases with resected pathological stage II-III epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma (EGFR-mt). METHODS: Between January 2008 and November 2018, we retrospectively reviewed 387 consecutive patients with pathological stage II-III lung adenocarcinoma who underwent surgical resection. We examined the EGFR mutation status (wild-type or mutant) and the evaluated clinicopathological features of all patients. In addition, tumor-promoting cancer-associated fibroblasts (CAFs), tumor-associated M2 macrophages (TAMs), and tumor-infiltrating lymphocytes (TILs) in the tumor microenvironment of EGFR-mt cells were evaluated by immunohistochemical analysis. RESULTS: EGFR-mt (n = 124, 32 %) had more lymph node and pulmonary metastases than EGFR-wild-type lung adenocarcinoma (EGFR-wt) despite the smaller invasive component size. The disease-free survival (DFS) of patients with EGFR-mt tended to be shorter than that of patients with EGFR-wt. In the analysis according to the predominant subtype, EGFR-mt with papillary-predominant subtype had a significantly shorter 5-year DFS than that of EGFR-wt with papillary-predominant subtype (15.3 % vs. 44.1 %, p < 0.01). We observed no significant differences among the other subtypes. Multivariate analysis of DFS in patients with EGFR-mt revealed that male sex, pathological stage III, lymph node metastasis, pulmonary metastasis in the same lobe and non-acinar and non-lepidic predominant subtypes (papillary, solid, or micropapillary) were independent poor prognostic factors. Immunohistochemical analysis of EGFR-mt revealed that non-acinar- and non-lepidic-predominant subtypes were associated with a higher frequency of podoplanin-positive CAFs (36 % vs. 13 %, p = 0.01) and a higher median number of CD204-positive TAMs (61 vs. 49, p = 0.07) compared to the acinar- or lepidic-predominant subtypes. CONCLUSIONS: Non-acinar and non-lepidic predominant subtypes were predictors of recurrence and had an aggressive tumor microenvironment in pathological stage II-III EGFR-mt.

Clinical usefulness of the 3-tier classification according to the proportion of morphological patterns for patients with pathological stage I invasive lung adenocarcinoma.

OBJECTIVES: We classified pathological stage I invasive lung adenocarcinomas according to our 3-tier classification, which was based on the proportion of invasive morphological patterns as follows: (1) patients with each predominant subtype, (2) those with a minor histological subtype, even not the predominant subtype and (3) those without each invasive component. We aimed to evaluate the classification's clinical impact in survival, recurrence, malignant grade, and epidermal growth factor receptor (EGFR) mutational status. MATERIALS AND METHODS: A total of 1,269 patients with p-stage I lung adenocarcinoma underwent curative surgical resection between January 2008 and December 2017. Of these, 620 patients (48.9%) met the inclusion criteria of this study. RESULTS: Postoperative recurrence was observed in 81 patients (13.1%). Multivariate analysis showed that vascular invasion (hazard ratio, 2.61; p < 0.001) and p-stage IB (hazard ratio, 2.19; p = 0.001) were significantly associated with an unfavorable RFS, while the presence of acinar component (hazard ratio, 1.64; p = 0.052) or solid component (hazard ratio, 1.60; p = 0.074) were marginally significant. The presence of lepidic or papillary component and the absence of acinar or solid component significantly correlated with an increased proportion of lung adenocarcinomas harboring EGFR mutations. CONCLUSION: In patients with p-stage I invasive lung adenocarcinoma, it is beneficial to use not only the predominant subtype but analyzing the extent of each histological component based on our classification to predict patient prognoses and form appropriate postoperative follow-up methods.

Programmed death ligand 1 protein expression is positively correlated with the solid predominant subtype, high MIB-1 labeling index, and p53 expression and negatively correlated with epidermal growth factor receptor mutations in lung adenocarcinoma.

Programmed death ligand 1 (PD-L1) protein expression is a proposed predictive biomarker of immunotherapy; thus, identification of the clinicopathological and molecular characteristics associated with PD-L1 expression is important and necessary. We examined PD-L1 immunohistochemical expression and its relationships with the clinicopathological and molecular characteristics of patients with surgically resected nonsmall cell lung carcinoma. PD-L1 expression differed according to the histological subtype. Among 633 patients with adenocarcinoma, 523 (82.6%) had no PD-L1 expression, 78 (12.3%) low expression, and 32 (5.1%) high expression. PD-L1 expression was more common in men (p < 0.001), in smokers (p = 0.002), and in patients with a more advanced stage (p = 0.002), the solid predominant subtype (p < 0.001), no epidermal growth factor receptor(EGFR) mutations (p < 0.001), a high MIB-1 labeling index (p < 0.001), and positive p53 immunohistochemical expression (p < 0.001). In a multivariate logistic regression analysis, the solid predominant subtype (odds ratio [OR] = 4.92, 95% confidence interval [CI]: 2.72-8.89, p < 0.001), no EGFR mutations (OR = 2.27, 95% CI: 1.35-2.7, p = 0.002), a high MIB-1 labeling index (OR = 2.78, 95% CI: 1.72-4.55, p < 0.001), and p53 positivity (OR = 2.13, 95% CI: 1.34-4.36, p = 0.042) were significantly and independently associated with PD-L1 expression. The combination of the solid predominant subtype with a high MIB-1 labeling index was strongly associated with positive expression of PD-L1. In the 193 patients with squamous cell carcinoma, 92 (47.7%) had no PD-L1 expression, 57 (29.5%) low expression, and 44 (22.8%) high expression. There were no significant correlations between PD-L1 expression and the evaluated clinicopathological or molecular characteristics of these patients. These results, indicating associations of PD-L1 with various clinicopathological or molecular characteristics in adenocarcinoma but not squamous cell carcinoma, may be useful for selecting patients with a good response to immune checkpoint inhibitors.

Positive EGFR mutation status is a risk of recurrence in pN0-1 lung adenocarcinoma when combined with pathological stage and histological subtype: A retrospective multi-center analysis.

OBJECTIVES: Recurrence risk of resected lung adenocarcinoma is represented by pathological stage (pStage), histological subtype, and potentially by EGFR mutation. However, the relationship among these factors and their combined impact on prognosis are unclear. MATERIALS AND METHODS: Using a multicenter database, we retrospectively investigated the prognostic impact of EGFR mutation status in relation to pStage and histological subtype in resected pN0-1M0 lung adenocarcinoma. RESULTS: Among 1155 pN0-1M0 adenocarcinoma cases, pStage 0 and IA1-IB were confirmed predominantly in EGFR-positive cases. AIS, MIA, and lepidic predominant adenocarcinoma were also more frequently found in EGFR-positive cases and showed no/little recurrence regardless of EGFR mutation status. The 5-year recurrence-free survival (RFS) of papillary, acinar, solid, and micropapillary predominant adenocarcinoma was stratified by pStage (IA1-IB, IIA-IIIA) or histological malignant subtype (intermediate or high malignant subtype), and more finely subdivided by EGFR mutation status. Positive EGFR mutation cases showed worse RFS in both classifications. Low malignant subtype and pStage IA1-IB intermediate malignant subtype showed low frequency of recurrence. Whereas, in pStage IA1-IB high malignant subtype and pStage IIA-IIIA cases, EGFR-positive cases showed poorer 5-year RFS than EGFR-negative (49.6% and 75.6%, respectively, hazard ratio [HR] = 1.84, 95% CI = 1.38-7.42, p <  0.01) and multivariate analysis indicated positive EGFR mutation status was significantly related to poorer PRF (HR = 2.005, 95% CI = 1.029-3.906, p =  0.041). CONCLUSION: EGFR mutation harbored primarily in early-stage or low-malignant histological subtypes with no/little recurrence. In pN0-1M0 adenocarcinoma with higher risk of recurrence, positive EGFR mutation cases showed worse RFS. EGFR mutation status enables better stratification of recurrence risk when considering pStage and histological malignant subtype.

Both the presence of a micropapillary component and the micropapillary predominant subtype predict poor prognosis after lung adenocarcinoma resection: a meta-analysis.

OBJECTIVE: It has been confirmed that the micropapillary (MP) pattern is a poor prognostic factor after resection of lung adenocarcinoma (ADC), but the proportion of the MP component as a prognostic criterion is still controversial. Hence, a meta-analysis was performed to evaluate whether the presence of an MP component has equal prognostic power as the MP predominant subtype. METHODS: Literature retrieval was performed in the MEDLINE, EMBASE, and Cochrane databases until December 23, 2019. Eligible studies were selected based on the inclusion and exclusion criteria. The included studies were divided into two subgroups, the MP component subgroup and the MP predominant subgroup, according to the proportion of the MP pattern to analyse the effect of this pattern on disease-free survival (DFS) and overall survival (OS). The hazard ratio (HR) and 95% confidence interval (CI) were extracted from each study. Review Manager 5.3 was used for statistical analyses. RESULTS: Finally, 10 studies, including a total of 4934 lung ADC patients, were included in this meta-analysis. Our results indicated a significantly worse pooled DFS (HR 1.62, 95% CI 1.20-2.21) and OS (HR 1.53, 95% CI 1.19-1.96) in the subgroup of MP predominant subtype patients. The pooled DFS (HR 1.80, 95% CI 1.45-2.85) and OS (HR 2.26, 95% CI 1.46-3.52) were also poor in the subgroup of patients with the presence of an MP component. CONCLUSIONS: Both the presence of an MP component and the MP predominant subtype are related to poor DFS and OS after lung ADC resection and represent adverse prognostic factor for lung ADC patients. However, there are some limitations in this meta-analysis, and quantitative stratification based on the proportion of the MP component is needed to explore its effect on prognosis of lung ADC patients in the future.

Does the histologic predominance of pathological stage IA lung adenocarcinoma influence the extent of resection?

OBJECTIVES: We studied whether histologic subtype according to the new IASLC/ATS/ERS adenocarcinoma classification influences the extent of resection in patients with pathological stage IA lung adenocarcinoma. METHODS: Data on 288 patients with pathological stage IA lung adenocarcinoma were analyzed retrospectively. Recurrence-free survival (RFS) rates were compared according to clinicopathological characteristics, including predominant histologic subtype and extent of resection. RESULTS: Median follow-up was 38.9 months. Lobectomy was performed in 146 patients, and sublobar resection in 142 patients. When recurrence was compared among the low-grade group (adenocarcinoma in situ, AIS; minimally invasive adenocarcinoma, MIA), intermediate-grade group (lepidic, acinar, and papillary) and high-grade group (solid and micropapillary), the RFS rate decreased as the grade increased (p = 0.037). There was no recurrence in the low-grade or lepidic predominant groups. The recurrence pattern did not differ according to the type of resection or histological subtype. Even in the intermediate- and high-grade groups, the extent of resection was not significantly related to the RFS rate (p = 0.622, p = 0.516). The results were unchanged after adjusting for independent risk factors. The concordance rate between clinical and pathological stage IA was good in low (98.6%) and intermediate grade (84.6%) and poor in high grade (41.2%). CONCLUSIONS: AIS, MIA, and lepidic predominant may be curable by any type of complete resection. Even in invasive subtypes, lobectomy does not offer a recurrence-free advantage over sublobar resection. However, in the high-grade group, less than half of clinical stage IA was actually pathological stage IA. Physicians should exercise caution whenever sublobar resection is planned.

Clinicopathological significance of caveolin-1 expression by cancer-associated fibroblasts in lung adenocarcinoma.

PURPOSE: Caveolin is an essential constituent of caveolae and has many biological functions. Expression of caveolin-1 in cancer cells was reported to be a prognostic marker in several types of cancers, the prognostic significance of its expression in cancer-associated fibroblasts (CAFs) has not been investigated. This study aimed to evaluate the clinicopathological significance of expression by CAFs in lung adenocarcinoma. METHODS: We examined caveolin-1 expression in both CAFs and cancer cells in stage I invasive lung adenocarcinoma (n = 412) and analyzed the relationship between the expression and clinicopathological factors. RESULTS: Caveolin-1 expression by CAFs and cancer cells was observed in 12.1% and 7.8% of adenocarcinomas, respectively. Tumors with caveolin-1-positive CAFs had vascular and pleural invasion significantly more frequently than those with caveolin-1-negative CAF (p < 0.05). This was also the cases with tumors with caveolin-1-positive cancer cells (p < 0.01). Caveolin-1 expression by CAFs and that by cancer cells were significant predictors of shorter recurrence-free survival (p < 0.001). Caveolin-1 expression by CAFs and cancer cells was found in 25% and 30% of solid predominant subtype, respectively, but only 9.2% and 2.7% of non-solid predominant subtype, respectively. The frequency of cases with caveolin-1-positive CAFs or cancer cells was significantly higher in the solid predominant subtype than in non-solid predominant subtype (p < 0.001). CONCLUSIONS: Our current results highlight the prognostic importance of caveolin-1 expression by CAFs in stage I lung adenocarcinoma and provide new insights into the biological significance of caveolin-1 in the tumor microenvironment, especially in microenvironment of solid predominant adenocarcinoma.

Factors influencing the concordance of histological subtype diagnosis from biopsy and resected specimens of lung adenocarcinoma.

OBJECTIVES: Lung adenocarcinoma is heterogeneous, characterized by various histological subtypes. Determination of the predominant histological subtype (lepidic, papillary, acinar or solid-predominant) has been shown to correlate with genetic abnormalities and clinicopathological features. Although subtyping using small biopsy samples is important for tailored approaches to clinical management, limited data exist on the concordance of predominant subtype between resected specimens and biopsy specimens. MATERIALS AND METHODS: We compared the diagnosed predominant subtypes in resected specimens and matched biopsy specimens in a series of 327 lung adenocarcinomas. The accuracy of preoperative diagnosis by biopsy and the factors that influence concordance with resected specimen analysis were examined. RESULTS: In 211 of the 326 patients (66.0%), the predominant adenocarcinoma subtype diagnosed from biopsy matched the findings of resection analysis. Overall, the concordance rate in biopsy samples with larger tumor areas (≥ 0.7 mm(2)) was significantly higher than in those with smaller tumor area (<0.7 mm(2); 71.2% vs 60.7%, respectively; p=0.015). In the biopsy samples with smaller tumor areas, the concordance rate was 77% in lepidic subtype, 71% in papillary subtype, 60% in solid subtype, and 40% in acinar subtype. Concordance rate in the biopsy samples with larger tumor area was higher in papillary and solid subtypes (88% and 76%, respectively), but remained low in acinar subtype (37%). CONCLUSION: The current results indicate that accuracy of adenocarcinoma subtyping based on small biopsy samples is influenced by tumor area. Our study also suggests that subtyping of acinar histology using biopsy specimen is particularly error-prone.

The difference in Ezrin-pAkt signaling axis between lepidic and papillary predominant invasive adenocarcinomas of the lung.

PURPOSE: Histologic classification of invasive lung adenocarcinomas by predominant subtype has prognostic value. Papillary predominant adenocarcinoma (PPA) reportedly shows poorer prognosis than lepidic predominant adenocarcinoma (LPA); however, biological differences between PPA and LPA are unclear. The purpose of this study was to clarify biological differences between PPA and LPA. METHODS: Clinicopathological characteristics of invasive 62 PPAs and 117 LPAs smaller than 30 mm were investigated. Furthermore, we compared immunochemical staining scores of 9 molecular markers (E-cadherin, S100A4, fibronectin, integrinß1, ezrin, GLUT1, ALDH1, SOX2 and Nanog) between PPA and LPA. We performed Western blot analysis using ezrin shRNA-knockdown lung adenocarcinoma cell lines to examine whether molecules that are highly expressed in PPA, such as ezrin, affect pAkt. Finally, we performed immunochemical staining to compare pAkt expression level in PPA and LPA. RESULTS: Lymphovascular and pleural invasion and lymph node metastasis were significantly more often detected in PPA than in LPA (lymphatic permeation: 31 vs 3 %, vascular invasion: 35 vs 3 %, pleural invasion: 29 vs 5 %, lymph node metastasis: 18 vs 1 %; all P < 0.01). Immunohistochemical (IHC) study revealed that expression score of ezrin was significantly higher in PPA than in LPA (38.3 vs 15.0; P < 0.01). The level of pAkt decreased in shEzrin-induced PC-9 and A549 cancer cells. Moreover, the IHC staining score of pAkt was significantly higher in PPA than in LPA (13.3 vs 0.0; P < 0.01). CONCLUSIONS: Our results show that the activation of the ezrin-pAkt signaling axis is associated with the more aggressive clinicopathological features of PPA compared with LPA.

Prognostic value of the new IASLC/ATS/ERS classification of clinical stage IA lung adenocarcinoma.

OBJECTIVES: We analyzed and validated the prognostic utility of the new International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) for clinical stage IA lung adenocarcinoma (ADC) classification of adenocarcinoma (ADC). METHODS: We retrospectively reviewed 347 patients with clinical stage IA nonmucinous ADC, who had undergone complete resection. The histological subtype was classified according to the predominant subtype, as proposed by the new IASLC/ATS/ERS ADC classification. RESULTS: The histopathological subtypes, defined according to the new IASLC/ATS/ERS ADC classification, were ADC in situ (AIS) in 56 patients (16.1%), minimally invasive ADC (MIA) in 15 (4.3%), lepidic-predominant ADC in 109 (31.4%), papillary-predominant ADC in 70 (20.2%), acinar-predominant ADC in 61 (17.6%), solid-predominant ADC in 30 (8.6%), and micropapillary-predominant ADC in 6 (1.7%). The 5-year disease-free survival (DFS) rate was 100% for both AIS and MIA. All cases of recurrence involved invasive ADC. The 5-year DFS for lepidic-predominant ADC was 99.0%; acinar-predominant ADC, 82.4%; papillary-predominant ADC, 80.8%; solid-predominant ADC, 73.6%; and micropapillary-predominant ADC, 33.3%. The predominant subtype of ADC was significantly correlated with DFS (P<0.0001). Multivariate analysis indicated that the pathological stage was an independent predictor of DFS (P=0.031). Other independent predictors of increased risk of recurrence were the presence of vascular or lymphatic invasion (HR=4.96, P=0.001), and a pathological stage more advanced than IB (HR=2.87, P=0.010). The coincidence between the clinical stage and pathological stage was 79.8%. The stage migration was found in 53.3% of solid-predominat ADC and in 83.3% of micropapillary-predominant ADC. CONCLUSION: The new IASLC/ATS/ERS ADC classification has prognostic value in predicting the recurrence and survival of patients with clinical stage IA ADC. The frequency of stage migration was found in more than half of solid and micropapillary predominant ADCs.