Clinical Significance of Complex Glandular Patterns in Lung Adenocarcinoma: Clinicopathologic and Molecular Study in a Large Series of Cases

Real-world applications of the new grading system in lung adenocarcinoma: A study of 907 patients focusing on revealing the relationship between pathologic grade and genetic status

BACKGROUND

The status of the lung adenocarcinoma (LUAD) grading system and the association between LUAD differentiation, driver genes, and clinicopathological features remain to be elucidated.

METHODS

We included patients with invasive non-mucinous LUAD, evaluated their differentiation, and collected available clinicopathological information, gene mutations, and analyzed clinical outcomes.

RESULTS

Among the 907 patients with invasive non-mucinous LUAD, 321 (35.4 %) were poorly differentiated, 422 (46.5 %) were moderately differentiated, and 164 (18.1 %) were well differentiated. EGFR mutation was more common in the LUADs accompanied without CGP (complex glandular pattern) than LUADs with CGP (p < 0.001). Correlation analysis between mutations and clinical characteristics showed that EGFR gene mutation (p < 0.001), KRAS gene mutation (p < 0.05), and ALK gene rearrangement (p < 0.001) were significantly related to the degree of tumor differentiation, and the KRAS and ALK gene mutation frequencies were higher in the low-differentiation group than in the high and medium differentiation groups. The EGFR mutation frequency was higher in the well/moderately differentiated adenocarcinoma group.

CONCLUSIONS

Our study adds to the evidence regarding the role of the grading system in prognosis. EGFR, KRAS, and ALK are related to the degree of tumor differentiation.

Prognostic impact of the IASLC grading system of lung adenocarcinoma: a systematic review and meta-analysis

AIMS

Tumour grading is an essential part of the pathologic assessment that promotes patient management. The International Association for the Study of Lung Cancer (IASLC) proposed a grading system for non-mucinous lung adenocarcinoma in 2020. We aimed to validate the prognostic impact of this novel grading system on overall survival (OS) and recurrence-free survival (RFS) based on literature data.

METHODS AND RESULTS

The review protocol was registered in PROSPERO (CRD42023396059). We aimed to identify randomized or non-randomized controlled trials published after 2020 comparing different IASLC grade categories in Medline, Embase, and CENTRAL. Hazard ratios (HRs) with 95% confidence intervals (CIs) of OS and RFS were pooled and the Quality In Prognosis Studies (QUIPS) tool was used to assess the risk of bias in the included studies. Ten articles were eligible for this review. Regarding OS estimates, grade 1 lung adenocarcinomas were better than grade 3 both in univariate and multivariate analyses (HROSuni = 0.19, 95% CI: 0.05-0.66, p = 0.009; HROSmulti = 0.21, 95% CI: 0.12-0.38, p < 0.001). Regarding RFS estimates, grade 3 adenocarcinomas had a worse prognosis than grade 1 in multivariate analysis (HRRFSmulti: 0.22, 95% CI: 0.14-0.35, p < 0.001).

CONCLUSION

The literature data and the result of our meta-analysis demonstrate the prognostic relevance of the IASLC grading system. This supports the inclusion of this prognostic parameter in daily routine worldwide.

The presence of a cribriform pattern is related to poor prognosis in lung adenocarcinoma after surgical resection: A meta-analysis

OBJECTIVE

Previous studies reported that the cribriform pattern (CP) was associated with poor prognosis in lung adenocarcinoma (ADC) patients; therefore, a meta-analysis was performed to thoroughly evaluate the prognostic impact of cribriform pattern in postoperative ADC patients.

METHODS

Eligible studies were retrieved from PubMed, Embase databases, and Web of Science until April 2023. Studies evaluating the effect of the cribriform pattern on the prognosis of postoperative ADC patients were included. Subsequently, subgroup analysis was conducted according to the proportion of the cribriform pattern, with disease-free survival (DFS) and/or overall survival (OS) as outcomes. Hazard ratios (HRs) and 95% confidence intervals (CIs) were used as effect estimates in the meta-analyses, which were performed with a random-effects model despite the heterogeneity.

RESULTS

Nine studies published between 2015 and 2022 were included, with 4,289 ADC patients in total. The pooled results revealed a significantly poorer DFS (HR1.56, 95%CI 1.18-2.06, P = 0.11, I2 = 45%) and OS (HR2.11, 95%CI 1.63-2.72, P = 0.01, I2 = 56%) in patients with the cribriform pattern. Furthermore, the subgroup analysis showed that patients with a cribriform pattern (DFS: HR1.32, 95% CI 1.04-1.68 OS:HR2.30, 95% CI 1.55-3.39) and patients with a predominantly cribriform pattern (DFS:HR2.04, 95% CI 1.32--3.15 OS: HR1.92, 95% CI 1.41-2.61) were associated with poor prognosis.

CONCLUSIONS

The presence of a cribriform pattern is related to poor prognosis in postoperative ADC patients, despite not being a main tumor component. However, the results should be confirmed by large-scale and prospective studies owing to the small sample and potential heterogeneity.

EGFR mutation impacts recurrence in high-risk early-stage lung adenocarcinoma in the IASLC grading system

INTRODUCTION

The developments of perioperative treatments for patients with high-risk early-stage lung cancer are ongoing, however, real-world data and evidence of clinical significance of genetic aberration are lacking in this population. This study aimed to identify patients with early-stage lung adenocarcinoma at high risk for recurrence based on pathological indicators of poor prognosis, including the International Association for the Study of Lung Cancer (IASLC) grade, and elucidate the prognostic impact of epidermal growth factor receptor mutation (EGFRm) status.

METHODS

This retrospective study included 494 consecutive patients who underwent complete resection for pathological stage I lung adenocarcinoma between 2011 and 2016. The patients were evaluated for EGFRm and IASLC grade. Multivariable analysis was used to identify pathological factors for poor prognosis associated with recurrence-free survival (RFS) and overall survival (OS). Patients with any one of these factors were classified into the high-risk group. The prognostic impact of EGFRm was evaluated using RFS, OS, and cumulative recurrence proportion.

RESULTS

Multivariable analysis for RFS and OS revealed that IASLC grade 3, pathological invasion size>2 cm, and presence of lymphovascular invasion were indicators of poor prognosis. EGFRm-positive patients had a higher incidence of all types of recurrence, including central nervous system (CNS) metastasis and distant metastasis in high-risk group, but not in low-risk group.

CONCLUSIONS

This study provides evidence that patients with EGFRm-positive stage I lung adenocarcinoma in the high-risk group have an increased risk of recurrence, including CNS metastasis. These findings highlight the need for development of adjuvant treatment in this population.

Proteomic analysis reveals LRPAP1 as a key player in the micropapillary pattern metastasis of lung adenocarcinoma

Objectives

Lung adenocarcinomas have different prognoses depending on their histological growth patterns. Micropapillary growth within lung adenocarcinoma, particularly metastasis, is related to dismal prognostic outcome. Metastasis accounts for a major factor leading to mortality among lung cancer patients. Understanding the mechanisms underlying early stage metastasis can help develop novel treatments for improving patient survival.

Methods

Here, quantitative mass spectrometry was conducted for comparing protein expression profiles among various histological subtypes, including adenocarcinoma in situ, minimally invasive adenocarcinoma, and invasive adenocarcinoma (including acinar and micropapillary [MIP] types). To determine the mechanism of MIP-associated metastasis, we identified a protein that was highly expressed in MIP. The expression of the selected highly expressed MIP protein was verified via immunohistochemical (IHC) analysis and its function was validated by an in vitro migration assay.

Results

Proteomic data revealed that low-density lipoprotein receptor-related protein-associated protein 1 (LRPAP1) was highly expressed in MIP group, which was confirmed by IHC. The co-expressed proteins in this study, PSMD1 and HSP90AB1, have been reported to be highly expressed in different cancers and play an essential role in metastasis. We observed that LRPAP1 promoted lung cancer progression, including metastasis, invasion and proliferation in vitro and in vivo.

Conclusion

LRPAP1 is necessary for MIP-associated metastasis and is the candidate novel anti-metastasis therapeutic target.

Clinicopathological significances of cribriform pattern in lung adenocarcinoma

The present study aimed to investigate the clinicopathological and prognostic implications of the cribriform pattern in lung adenocarcinoma through a meta-analysis. The estimated rates of cribriform pattern in lung adenocarcinomas were investigated. The correlations between cribriform pattern and clinicopathological characteristics, including genetic alterations and prognosis were evaluated. The estimated rate of cribriform pattern was 0.150 (95% confidence interval [CI], 0.101-0.218) in lung adenocarcinoma. The estimated rates of cribriform pattern in the 5% and 10% criteria were 0.230 (95% CI 0.125-0.386) and 0.130 (95% CI 0.062-0.252), respectively. The presence of cribriform pattern was significantly correlated with larger tumor size (> 30 mm), spread through air spaces, and lymph node metastasis (P < 0.001, P < 0.001, and P = 0.007, respectively, in the meta-regression test). There were no significant differences between cribriform pattern, smoking history, and vascular and lymphatic invasion. In lung adenocarcinoma with cribriform pattern, the estimated rates of ALK rearrangement, KRAS, and EGFR mutations were 0.407 (95% CI 0.165-0.704), 0.330 (95% CI 0.117-0.646), and 0.249 (95% CI 0.125-0.437), respectively. ALK rearrangement was significantly more frequent in lung adenocarcinomas with cribriform pattern than in those without. The overall survival rate was significantly worse in lung adenocarcinomas with a cribriform pattern than in those without (hazard ratio 2.051, 95% CI 1.369-3.075). In conclusion, the presence of a cribriform pattern can be a useful predictor of the clinicopathological characteristics and prognosis of patients with lung adenocarcinoma.

Standardized Classification of Lung Adenocarcinoma Subtypes and Improvement of Grading Assessment Through Deep Learning

The histopathologic distinction of lung adenocarcinoma (LADC) subtypes is subject to high interobserver variability, which can compromise the optimal assessment of patient prognosis. Therefore, this study developed convolutional neural networks capable of distinguishing LADC subtypes and predicting disease-specific survival, according to the recently established LADC tumor grades. Consensus LADC histopathologic images were obtained from 17 expert pulmonary pathologists and one pathologist in training. Two deep learning models (AI-1 and AI-2) were trained to predict eight different LADC classes. Furthermore, the trained models were tested on an independent cohort of 133 patients. The models achieved high precision, recall, and F1 scores exceeding 0.90 for most of the LADC classes. Clear stratification of the three LADC grades was reached in predicting the disease-specific survival by the two models, with both Kaplan-Meier curves showing significance (P = 0.0017 and 0.0003). Moreover, both trained models showed high stability in the segmentation of each pair of predicted grades with low variation in the hazard ratio across 200 bootstrapped samples. These findings indicate that the trained convolutional neural networks improve the diagnostic accuracy of the pathologist and refine LADC grade assessment. Thus, the trained models are promising tools that may assist in the routine evaluation of LADC subtypes and grades in clinical practice.

Complex glandular pattern is an aggressive morphology that predicts poor prognosis of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignant neoplasm with various morphologies. Recognition of histological patterns that can predict prognosis is important in pathological examination. Recently, the complex glandular pattern was defined as a morphology associating the poor prognosis in lung adenocarcinoma. We investigated the significance of the complex glandular pattern in PDAC by performing a retrospective analysis. Among 240 consecutive cases of conventional PDACs, 21 cases in which complex glandular pattern constituted >50 % of the total tumor volume (CG-PDACs) were identified. The prevalence of CG-PDAC was 8.8 % among all preoperative therapy-naïve and surgically resected conventional PDACs. Compared to the control PDACs (n = 95), the CG-PDACs were characterized by significantly higher prevalence of small- to medium-sized artery invasion (71.4 % vs. 14.7 %, p < 0.0001), intratumoral necrosis (59.1 % vs. 16.8 %, p < 0.0001), tumor budding (mean: 15.5 vs. 12.5 per 0.785 mm², p = 0.04), significantly higher Ki67 proliferative index (mean: 75.0 % vs. 54.7 %, p < 0.0001), and the HNF1α-/KRT81+ (quasi-mesenchymal) immunophenotype (42.9 % vs. 19.0 %, p = 0.004). In Kaplan-Meier analyses, the CG-PDAC patients achieved significantly worse disease-free survival (DFS) and overall survival (OS) compared to the control PDAC patients; the respective median DFS and OS were 6.3 and 17.7 months for CG-PDACs, and 22.6 and 52.8 months for control PDACs. A multivariate Cox regression analysis showed that predominance of complex glandular pattern was an independent prognostic factor (hazard ratio: 2.95; 95 % confidence interval: 1.46-5.98; p = 0.003). Our results provide new insights into the complex glandular pattern in conventional PDACs as a novel and potentially useful prognostic factor.

[Advances in the Study of Invasive Non-mucinous Adenocarcinoma with Different Pathological Subtypes]

Lung cancer is the leading cause of cancer death in the world today, and adenocarcinoma is the most common histopathological type of lung cancer. In May 2021, World Health Organization (WHO) released the 5th edition of the WHO classification of thoracic tumors, which classifies invasive non-mucinous adenocarcinoma (INMA) into lepidic adenocarcinoma, acinar adenocarcinoma, papillary adenocarcinoma, solid adenocarcinoma, and micropapillary adenocarcinoma based on its histological characteristics. These five pathological subtypes differ in clinical features, treatment and prognosis. A complete understanding of the characteristics of these subtypes is essential for the clinical diagnosis, treatment options, and prognosis predictions of patients with lung adenocarcinoma, including recurrence and progression. This article will review the grading system, morphology, imaging prediction, lymph node metastasis, surgery, chemotherapy, targeted therapy and immunotherapy of different pathological subtypes of INMA.
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Proposal of a revised International Association for the Study of Lung Cancer grading system in pulmonary non-mucinous adenocarcinoma: The importance of the lepidic proportion

OBJECTIVES

We aimed to measure the validity of the International Association for the Study of Lung Cancer (IASLC) grading system in Korean patients and propose a modification for an increase of its predictability, especially in grade 2 patients.

MATERIALS AND METHODS

From 2012 to 2017, histopathologic characteristics of 1358 patients with invasive pulmonary adenocarcinoma (stage I-III) from two institutions were retrospectively reviewed and re-classified according to the IASLC grading system. Considering the amount of the lepidic proportion, the validity of the revised model (Lepidic-10), derived from the training cohort (hospital A), was measured using the validation cohort (hospital B). Its predictability was compared to that of the IASLC system.

RESULTS

Of the 1358 patients, 259 had a recurrence, and 189 died during follow-up. The Harrell's concordance index and area under the curve of the IASLC system were 0.685 and 0.699 for recurrence-free survival (RFS) and 0.669 and 0.679 for death, respectively. From the training cohort, the IASLC grade 2 patients were divided into grades 2a and 2b (Lepidic-10 model) with a 10 % lepidic pattern. This new model further distinguished patients in both institutions that had better performance than the IASLC grading (Hospital A, p < 0.001 for RFS and death; Hospital B, p = 0.0215 for RFS, p = 0.0429 for death).

CONCLUSION

The IASLC grading system was easily applicable; its clinical use in predicting the prognosis of Korean patients with pulmonary adenocarcinoma was validated. Furthermore, the introduction of the lepidic proportion as an additional criterion to differentiate grade 2 patients improved its predictability.

Validation of the novel International Association for the Study of Lung Cancer grading system and prognostic value of filigree micropapillary and discohesive growth pattern in invasive pulmonary adenocarcinoma

INTRODUCTION

The Pathology Committee of the International Association for the Study of Lung Cancer (IASLC) proposed a new histological grading system based on the combination of predominant and high-grade patterns in 2020.

MATERIALS AND METHODS

Pathological sections from 631 patients with stage I-III invasive lung adenocarcinoma were reviewed. We then determined the histological grade according to the new grading system and confirmed the pathological features that included the filigree micropapillary and discohesive growth pattern. Applying of the novel IASLC grading system in prognosis stratification was verified and the clinical significance of the pathological characteristics was explored.

RESULTS

Cox multivariable analysis revealed that in the stage I-III invasive lung adenocarcinoma, the IASLC grading system was significantly associated with disease-free survival (DFS) [hazard ratio (HR) = 1.419; 95 % confidence interval (CI): 1.040-1.937; P = 0.027] and overall survival (OS) (HR = 1.899; 95 % CI: 1.168-3.087; P = 0.010). In patients with IASLC Grades 1 and 2, the simultaneous presence of filigree micropapillary and discohesive growth pattern was significantly correlated with DFS (HR = 1.899; 95 % CI:1.168-3.087; P = 0.010). However, the filigree micropapillary and discohesive growth pattern did not affect the OS (HR = 2.786; P = 0.317). The competitive risk model revealed that in the stage I cohort, the simultaneous presence of filigree micropapillary and discohesive growth pattern was a risk factor for recurrence and metastasis [sub- distribution HR (SHR) = 1.987; 95 %CI: 1.122-3.518; P = 0.019].

CONCLUSION

Our study verified that the new prognostic stratification system was an effective stratification tool. Filigree micropapillary and discohesive growth pattern may also be risk factors for DFS, postoperative recurrence and metastasis.

The new IASLC grading system for invasive non-mucinous lung adenocarcinoma is a more useful indicator of patient survival compared with previous grading systems

BACKGROUND

The International Association for the Study of Lung Cancer (IASLC) Pathology Committee recently proposed a new histological grading system for invasive lung adenocarcinoma (ADC). This study evaluated the usefulness of this grading system.

METHODS

A total of 395 patients with ADC were examined. ADCs were reclassified based on comprehensive histological subtyping according to the IASLC grading system. We evaluated the following histological grading systems for invasive ADC: the architectural (Arch), Sica's grading, and IASLC grading systems. Multivariate analyses of overall and recurrence-free survival (RFS) based on these three grading systems were performed using Cox proportional hazards models.

RESULTS

Multivariate analysis showed that all three grading systems were useful for predicting the outcomes of patients at all stages. However, the IASLC grading system was superior to the Arch and Sica's grading systems in differentiating grade 3 from grade 1 ADCs in terms of both overall survivals (IASLC vs. Arch vs. Sica's grading systems: hazard ratio [HR] = 3.77 vs. 3.03 vs. 2.63) and RFS (HR = 4.25 vs. 2.69 vs. 2.4).

CONCLUSION

The newly proposed IASLC grading system was useful for predicting patient outcomes and was superior to the other grading systems in detecting high-grade malignancy.

Prognostic and predictive value of the newly proposed grading system of invasive pulmonary adenocarcinoma in Chinese patients: a retrospective multicohort study

Our aim was to validate and analyze the prognostic impact of the novel International Association for the Study of Lung Cancer (IASLC) Pathology Committee grading system for invasive pulmonary adenocarcinomas (IPAs) in Chinese patients and to evaluate its utility in predicting a survival benefit from adjuvant chemotherapy (ACT). In this multicenter, retrospective, cohort study, we included 926 Chinese patients with completely resected stage I IPAs and classified them into three groups (Grade 1, n = 119; Grade 2, n = 431; Grade 3, n = 376) according to the new grading system proposed by the IASLC. Recurrence-free survival (RFS) and overall survival (OS) were estimated by the Kaplan-Meier method, and prognostic factors were assessed using univariable and multivariable Cox proportional hazards models. All included cohorts were well stratified in terms of RFS and OS by the novel grading system. Furthermore, the proposed grading system was found to be independently associated with recurrence and death in the multivariable analysis. Among patients with stage IB IPA (N = 490), the proposed grading system identified patients who could benefit from ACT but who were undergraded by the adenocarcinoma (ADC) classification. The novel grading system not only demonstrated prognostic significance in stage I IPA in a multicenter Chinese cohort but also offered clinical value for directing therapeutic decisions regarding adjuvant chemotherapy.

High-grade tumor classified by new system is a prognostic predictor in resected lung adenocarcinoma

OBJECTIVES

A grading system for pulmonary adenocarcinoma has not been established; hence, the International Association for the Study of Lung Cancer (IASLC) pathology panel developed a new grading system for invasive adenocarcinoma. We aimed to evaluate the prognostic significance of the IASLC grading system for invasive pulmonary adenocarcinoma.

METHODS

We conducted a retrospective analysis of 471 Japanese patients with resected lung adenocarcinoma. Tumors were classified in accordance with the IASLC grading system and 2015 World Health Organization classification. We analyzed recurrence-free probability (RFP) and overall survival (OS) using the log-rank test and compared the two grading systems using the Cox proportional hazards model.

RESULTS

Grade 3 tumors of the IASLC system and high-grade tumors of the 2015 World Health Organization classification were present in 38% and 17% of patients, respectively. The 5-year RFP was lower in patients with IASLC Grade 3 tumors (45%) than in patients with IASLC Grade 1 and 2 tumors (91% and 83%, respectively). The 5-year RFP of patients with IASLC Grade 2 tumors (83%) was higher than of those with 2015 World Health Organization intermediate tumors (69%). On multivariate analysis for recurrence, IASLC Grade 3 was an independent prognostic factor of worse RFP. We showed similar results on analysis for the OS.

CONCLUSIONS

The prognostic significance of IASLC Grade 3 tumors on recurrence-free probability was confirmed through both univariate and multivariate analyses. Thus, the IASLC Grade 3 tumor is an independent factor of poor prognosis in patients with resected lung adenocarcinoma.

Computational detection of a genome instability-derived lncRNA signature for predicting the clinical outcome of lung adenocarcinoma

Evidence has been emerging of the importance of long non-coding RNAs (lncRNAs) in genome instability. However, no study has established how to classify such lncRNAs linked to genomic instability, and whether that connection poses a therapeutic significance. Here, we established a computational frame derived from mutator hypothesis by combining profiles of lncRNA expression and those of somatic mutations in a tumor genome, and identified 185 candidate lncRNAs associated with genomic instability in lung adenocarcinoma (LUAD). Through further studies, we established a six lncRNA-based signature, which assigned patients to the high- and low-risk groups with different prognosis. Further validation of this signature was performed in a number of separate cohorts of LUAD patients. In addition, the signature was found closely linked to genomic mutation rates in patients, indicating it could be a useful way to quantify genomic instability. In summary, this research offered a novel method by through which more studies may explore the function of lncRNAs and presented a possible new way for detecting biomarkers associated with genomic instability in cancers.

Adenocarcinoma of High-Grade Patterns Associated with Distinct Outcome of First-Line Chemotherapy or EGFR-TKIs in Patients of Relapsed Lung Cancer

Purpose

High-grade patterns (micropapillary/solid/complex gland) are associated with a higher recurrence rate and shorter disease-free survival. Thus far, it remains unclear whether the efficacy of first-line anticancer therapy is different from that of the other adenocarcinoma subgroups for patients with high-grade patterns. The study aimed to investigate the association between an adenocarcinoma with high-grade patterns with the outcomes of first-line treatment in patients with lung cancer.

Patients and Methods

Patients with a high-grade pattern adenocarcinoma (more than 20% of micropapillary/solid components/complex glandular patterns) were retrospectively analyzed between June 2015 and June 2017. Patients’ clinical characteristics and treatment outcomes were compared with those of the remaining control adenocarcinoma subgroups.

Results

In total, 239 patients with adenocarcinoma, including 115 (48.1%) high-grade patterns and 124 (51.9%) control groups, were enrolled. Patients’ clinical characteristics such as age, sex, smoking status, and stage were similar between the two groups. Among them, 108 patients received first-line chemotherapy, and 131 received epidermal growth factor receptor–tyrosine kinase inhibitors (EGFR-TKIs). In the chemotherapy group, adenocarcinoma of high-grade patterns had a significantly lower objective response rate (ORR; 15.6% vs 36.4%, P=0.045), shorter progression-free survival (PFS; median 4.1 vs 5.4 months, P=0.007) and overall survival (OS, median 19.6 vs 23.8 months, P=0.048) compared with the control group. As for these treated with EGFR-TKIs, a similar ORR (70.7% vs 72.1%, P=0.703), PFS (median 11.3 vs 13.9 months, P=0.065) and OS (median 34.1 vs 29.6%, p=0.575) were observed between these two groups.

Conclusion

An adenocarcinoma with high-grade patterns is associated with inferior outcomes to first-line chemotherapy in relapsed lung cancer. Patients who received chemotherapy had a significantly shorter PFS and OS and lower ORR than control subjects, while there was no difference in the EGFR-TKI cohort. This study is the first to report the distribution of adenocarcinoma with high-grade patterns.

Cribriform colon cancer: a morphological growth pattern associated with extramural venous invasion, nodal metastases and microsatellite stability

BACKGROUND

Cribriform comedo-type adenocarcinoma was a colon cancer subtype recognised in the previous WHO classification of tumours that is no longer included in the recent edition. Previous reports have described colon cancers with cribriform growth as having worse overall survival and being associated with microsatellite stability. We sought to validate whether cribriform carcinoma (CC) is a distinct morphological subtype with clinical relevance in the context of modern colon cancer diagnosis.

METHODS

Consecutive cases of non-neoadjuvantly treated colon cancer resections were identified (n=177) and reviewed to evaluate for CC and other histopathological and clinical features. CC was defined as solid nests of cancer with round, 'punched out' spaces and intraluminal bridges, reminiscent of ductal carcinoma in situ of the breast.

RESULTS

CC was present in 18.6% of the consecutive case cohort. Compared with all other cases, CC was associated with positive lymph nodes, increased depth of invasion, extramural venous involvement (EMVI), and microsatellite stability, and was less likely to have tumour infiltrating lymphocytes (p<0.05). In contrast to previous reports, we did not find significantly worse overall, disease-specific or recurrence-free survival for CC. Morphological features mimicking CC occurred in 33.3% of all other colon cancer cases.

CONCLUSION

Identifying CC may be useful due to its association with worse stage at presentation and EMVI, but given that cribriform-like appearance may be found in many colon cancer cases and that we did not find a survival difference for CC, CC may not necessitate its own subtype classification.

Molecular biomarkers in early stage lung cancer

Low dose computed tomography (LDCT) screening, together with the recent advances in targeted and immunotherapies, have shown to improve non-small cell lung cancer (NSCLC) survival. Furthermore, screening has increased the number of early stage-detected tumors, allowing for surgical resection and multimodality treatments when needed. The need for improved sensitivity and specificity of NSCLC screening has led to increased interest in combining clinical and radiological data with molecular data. The development of biomarkers is poised to refine inclusion criteria for LDCT screening programs. Biomarkers may also be useful to better characterize the risk of indeterminate nodules found in the course of screening or to refine prognosis and help in the management of screening detected tumors. The clinical implications of these biomarkers are still being investigated and whether or not biomarkers will be included in further decision-making algorithms in the context of screening and early lung cancer management still needs to be determined. However, it seems clear that there is much room for improvement even in early stage lung cancer disease-free survival (DFS) rates; thus, biomarkers may be the key to refine risk-stratification and treatment of these patients. Clinicians’ capacity to register, integrate, and analyze all the available data in both high risk individuals and early stage NSCLC patients will lead to a better understanding of the disease’s mechanisms, and will have a direct impact in diagnosis, treatment, and follow up of these patients. In this review, we aim to summarize all the available data regarding the role of biomarkers in LDCT screening and early stage NSCLC from a multidisciplinary perspective. We have highlighted clinical implications, the need to combine risk stratification, clinical data, radiomics, molecular information and artificial intelligence in order to improve clinical decision-making, especially regarding early diagnostics and adjuvant therapy. We also discuss current and future perspectives for biomarker implementation in routine clinical practice.

Prognostic significance of cribriform adenocarcinoma of the lung: validation analysis of 1,057 Japanese patients with resected lung adenocarcinoma and a review of the literature

Background

Cribriform-predominant adenocarcinoma of the lung (Cribri-ADC) is a recently described tumor growth pattern. However, its prognostic impact has not been clearly determined. We analyzed the data of a series of 1,057 Japanese patients with resected lung adenocarcinoma to identify the clinical significance of Cribri-ADC.

Methods

Cribriform pattern (Cribri-p) is defined as invasive back-to-back fused tumor glands with poorly formed glandular spaces or invasive tumor nests comprising tumors cells that produced glandular lumina. We investigated the correlations of Cribri-p and Cribri-ADC with clinicopathological factors as well as disease-free survival (DFS) and overall survival (OS).

Results

Cribri-p was present in 217 patients (20.5%) and Cribri-ADC was determined in 25 patients (2.4%). Cribri-p was associated with larger tumor size, pleural invasion, vascular invasion, lymphatic invasion, and spreading through air spaces (STAS) (all, P<0.0001). Cribri-ADC was associated with younger age (P=0.019), vascular invasion (P=0.0025), STAS (P<0.0001), and ALK rearrangement (P=0.012). The DFS curve of patients with Cribri-ADC was identical to that of patients with solid adenocarcinoma; however, the OS curve was located between that of patients with papillary and acinar adenocarcinoma. Of the 10 patients who had tumor recurrences, eight had EGFR mutations or ALK rearrangement, six of whom achieved relatively long survival (median, 64.6, range, 37.4–113 months) following treatment with tyrosine kinase inhibitors (TKIs). In multivariate analysis, Cribri-ADC was not an independent prognostic factor of either recurrence or death.

Conclusions

Cribri-ADC is associated with a higher risk of recurrence; however, most patients can be successfully treated with TKIs.

Discohesive growth pattern (Disco-p) as an unfavorable prognostic factor in lung adenocarcinoma: an analysis of 1062 Japanese patients with resected lung adenocarcinoma

Discohesive growth pattern (Disco-p) is often observed in lung adenocarcinoma (ADC) and mimics tumor budding (TB), stromal invasive-type micropapillary pattern (SMPP), and complex glandular pattern. However, the clinical impact of Disco-p in lung ADC has not been well studied. To investigate the prognostic significance of Disco-p, we analyzed 1062 Japanese patients with resected lung ADC. Disco-p was defined as an invasive growth pattern composed of single tumor cells, or trabeculae or small nests of tumor cells associated with desmoplastic fibrous stroma. We recorded the percentage of Disco-p in 5% increments independent of the major histologic pattern and investigated its correlation with different clinicopathological factors. We also analyzed the overall survival (OS) and disease-free survival (DFS). Disco-p was observed in 203 tumors (19.1%). Disco-p was significantly associated with male sex, smoking, lymph node metastasis, large tumor size, high TNM stage, lymphovascular and pleural invasion, spread through air spaces, and TB (all, p < 0.001). Of the total cases, only eight cases exhibited a dubious pattern between SMPP and Disco-p. Disco-p was also associated with wild-type EGFR (p < 0.001) and ALK fusion (p = 0.008). Patients harboring tumors with Disco-p had significantly worse prognoses (OS and DFS (both, p < 0.001)) compared with those without Disco-p. On multivariate analysis, Disco-p was an independent prognostic factor of worse OS (hazard ratio (HR), 2.572; 95% confidence interval (CI), 1.789-3.680; p < 0.001), and DFS (HR, 3.413; 95% CI, 2.482-4.683; p < 0.001), whereas TB was not an independent unfavorable prognostic factor. Disco-p was an independent unfavorable prognostic factor in patients with resected lung ADC, although a careful evaluation is necessary to distinguish it from similar patterns. We proposed that Disco-p should be recognized as a new invasive pattern and accurately recorded for the better management of patients with lung ADCs.

High tumor mutation burden predicts favorable outcome among patients with aggressive histological subtypes of lung adenocarcinoma: A population-based single-institution study

OBJECTIVES

Tumor mutation burden (TMB) is an emerging predictive cancer biomarker. Few studies have addressed the prognostic role of TMB in non-small cell lung carcinoma, with conflicting results. Moreover, the association of TMB with different histological subtypes of lung adenocarcinoma has hitherto not been systematically evaluated. Here we studied the prognostic value of TMB and its distribution in different histological subtypes of lung adenocarcinomas in a retrospective cohort using the most recent updated classification guidelines.

MATERIALS AND METHODS

176 surgically resected stage I-IV lung adenocarcinomas were histologically reclassified according to WHO 2015 guidelines. A modified classification subdividing the acinar subtype into classic acinar, complex glandular and cribriform subtypes was further applied and potentially prognostic histopathological characteristics such as tumor-infiltrating lymphocytes were evaluated. 148 patients with stage I-III tumors and complete follow-up data were included in the survival analyses. TMB was determined by a commercial next generation sequencing panel from 131 tumors, out of which 105 had survival data available.

RESULTS

Predominant micropapillary, solid and complex glandular as well as nonpredominant cribriform histological subtypes were associated with significantly shorter survival. High TMB concentrated in micropapillary, solid and acinar predominant subtypes. Interestingly, TMB ≥ 14 mutations/MB conferred a stage- and histology-independent survival benefit compared to TMB < 14 in multivariable analysis for overall (HR 0.284, 95% CI 0.14-0.59, P=0.001) and disease-specific survival (HR 0.213, 95% CI 0.08-0.56, P=0.002).

CONCLUSION

TMB was an independent biomarker of favorable prognosis in our cohort of lung adenocarcinoma despite being associated with predominant histological subtypes considered aggressive.

Cribriform growth pattern in lung adenocarcinoma: More aggressive and poorer prognosis than acinar growth pattern

The predictive value of prognosis based on the histopathological subtype is a critical criterion in the new classification of lung adenocarcinoma published in 2011 by the International Association for the Study of Lung Cancer (IASLC), the American Thoracic Society (ATS), and the European Respiratory Society (ERS) (IASLC/ATS/ERS). In this new classification, the differences of histopathology and prognosis are two considerable parameters to classify the subtypes of lung adenocarcinoma. Cribriform growth pattern is regarded as a variant of acinar growth pattern in lung adenocarcinoma, however, more and more studies pointed out that cribriform growth pattern is associated with more aggressive histopathological structures, higher proportion of recurrence rates, and shorter postoperative survival than acinar growth pattern. These features are similar to solid or micropapillary predominant adenocarcinoma. In this review, we summarized the clinicopathological features, prognosis, and genetic variations of cribriform growth pattern of lung adenocarcinoma, and provided a novel insight into the diagnosis and treatment of cribriform lung adenocarcinoma.

[Progress in Research on the Cribriform Component in Lung Adenocarcinoma]

The morbidity of lung cancer ranks top in the world. At present, lung adenocarcinoma (LUAD) is the most common histologic type of lung cancer. However, the prognoses of LUAD patients with the same subtype remain heterogeneous. Histological heterogeneity is one of the main causes of diverse prognoses of patients with LUAD. Studies have shown that there are other histologic patterns that affect the clinical outcomes of LUAD patients, in addition to the five growth patterns of invasive LUAD classified by the World Health Organization (WHO) in 2015. The cribriform component (CC) is one of the research hotspots among histopathology of LUAD. Previous studies have shown that the presence of CC can further stratify the prognoses of patients with LUAD. Along with the progressively deep insights into the aforementioned topic, researchers are dedicating to unveiling the relationships among CC and and other clinicopathological factors as well as their joint influence on the survival of LUAD patients. The review manages to generalize the latest research progress in the CC in LUAD patients.

A Grading System for Invasive Pulmonary Adenocarcinoma: A Proposal From the International Association for the Study of Lung Cancer Pathology Committee

INTRODUCTION

A grading system for pulmonary adenocarcinoma has not been established. The International Association for the Study of Lung Cancer pathology panel evaluated a set of histologic criteria associated with prognosis aimed at establishing a grading system for invasive pulmonary adenocarcinoma.

METHODS

A multi-institutional study involving multiple cohorts of invasive pulmonary adenocarcinomas was conducted. A cohort of 284 stage I pulmonary adenocarcinomas was used as a training set to identify histologic features associated with patient outcomes (recurrence-free survival [RFS] and overall survival [OS]). Receiver operating characteristic curve analysis was used to select the best model, which was validated (n = 212) and tested (n = 300, including stage I-III) in independent cohorts. Reproducibility of the model was assessed using kappa statistics.

RESULTS

The best model (area under the receiver operating characteristic curve [AUC] = 0.749 for RFS and 0.787 for OS) was composed of a combination of predominant plus high-grade histologic pattern with a cutoff of 20% for the latter. The model consists of the following: grade 1, lepidic predominant tumor; grade 2, acinar or papillary predominant tumor, both with no or less than 20% of high-grade patterns; and grade 3, any tumor with 20% or more of high-grade patterns (solid, micropapillary, or complex gland). Similar results were seen in the validation (AUC = 0.732 for RFS and 0.787 for OS) and test cohorts (AUC = 0.690 for RFS and 0.743 for OS), confirming the predictive value of the model. Interobserver reproducibility revealed good agreement (k = 0.617).

CONCLUSIONS

A grading system based on the predominant and high-grade patterns is practical and prognostic for invasive pulmonary adenocarcinoma.

Controversies and challenges in the histologic subtyping of lung adenocarcinoma

Lung adenocarcinomas differ in prognosis based on their histologic growth pattern. Adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) both have an excellent prognosis when completely resected, whereas solid and micropapillary-predominant adenocarcinomas do not, with other patterns falling in between. In recent years, it has become apparent that even within histologic patterns, there are differences in appearance that are clinically important, such as complex acinar formations and highly variable-sized papillae. This review highlights prognostically important histologic features in lung adenocarcinoma that have emerged since implementation of the current World Health Organization (WHO) classification of lung adenocarcinoma.

Clinical significance of the cribriform pattern in invasive adenocarcinoma of the lung

PURPOSE

According to the WHO, the cribriform pattern is a subtype of acinar (Aci) predominance in invasive adenocarcinoma (ADC) of the lung. Recently, several studies have demonstrated poor prognosis in patients with cribriform predominance. This study was performed to examine the correlations of cribriform pattern with the clinicopathology, molecular features and prognosis in patients with invasive ADC.

METHODS

Histological subtypes were evaluated in 279 patients who underwent complete resection for invasive ADC. Patients of the Aci-predominant subtype were divided into two subgroups according to the percentage of cribriform cancer (≥5% vs <5%). Clinicopathological characteristics, overall survival (OS), disease-free survival (DFS) and molecular changes were compared. In addition, both OS and DFS were compared between patients with cribriform-predominant (n=33) and pure Aci-predominant (n=88) ADCs.

RESULTS

A cribriform pattern was found in 111 (39.8%) cases and ranged from 5 % to 100 % of the total tumour volume (mean±SEM, 30%±2%). Of 117 patients with Aci predominance, 79 showed the cribriform pattern, while the remaining 38 did not. The cribriform pattern was associated with aggressive pathological behaviour, including advanced stages of cancer, nuclear atypia, mitoses, lymph node invasion, metastasis and larger tumour size. The subgroup with cribriform cancer (≥5%) had significantly poorer OS and DFS compared with the cribriform-negative (<5%) group. In addition, Cox multivariate analyses revealed that the cribriform pattern was an independent predictor of OS but not DFS. Moreover, OS was significantly lower in the cribriform-predominant group than in the Aci-predominant group.

CONCLUSION

The cribriform pattern is associated with aggressive pathological behaviour and is an independent poor prognostic indicator in patients with Aci-predominant ADC of the lung.

Cribriform pattern in lung invasive adenocarcinoma correlates with poor prognosis in a Chinese cohort

The 2011 International　Association　for　the　Study　of　Lung　Cancer/American　Thoracic　Society/European　Respiratory　Society (IASLC/ATS/ERS) lung adenocarcinoma classification and the following 2015 WHO classification have both been validated for their predictive values of histologic subtypes for prognosis. We sought to investigate the clinicopathological and prognostic significance of the cribriform pattern in lung adenocarcinomas. Histologic subtypes were evaluated in 395 patients who underwent complete resection for invasive lung adenocarcinomas between 2011 and 2013. Cribriform pattern was correlated with clinicopathological factors as well as molecular and survival data. One hundred and thirty cases (33%) were present with cribriform pattern (5-100%; mean ± SD, 24% ± 22%). Thirty two (8%) of those were reclassified into cribriform predominant tumors. Presence of cribriform pattern (≥5%) was significantly associated with lymph/vascular invasion (P＜0.001), nodal positivity (P = 0.003), higher T stage(P = 0.005) and higher TNM stage (P = 0.001). Cribriform pattern (≥10%) was highly associated with worse disease-free survival (DFS) and overall survival (OS) (mean DFS: 42.6 months, P < 0.001; mean OS: 64.1 months, P = 0.012). The DFS or OS for cribriform predominant tumors was similar to that for solid or micropapillary tumors. In multivariate analysis, cribriform pattern (≥10%) or cribriform predominant subtype was an independent predictor for DFS. Cribriform pattern was a specific pattern compared to other acinar patterns, presenting with more aggressive behavior. Moreover, presence of cribriform pattern was a strong predictor for worse prognosis and should be considered a high grade pattern. Our study provides further evidence for cribriform pattern to be acknowledged as an independent subtype in the future classification.

Cribriform Subtype is an Independent Predictor of Recurrence and Survival After Adjustment for the Eighth Edition of TNM Staging System in Patients With Resected Lung Adenocarcinoma

INTRODUCTION

At present, cribriform arrangements are regarded as a pattern of acinar adenocarcinoma. However, recent studies have indicated that clinical outcomes for lung adenocarcinoma patients with cribriform subtype are unfavorable. To validate the prognostic significance of the cribriform pattern, we analyzed a series of 735 Japanese patients with resected lung adenocarcinoma, which was restaged according to the eighth edition of the TNM staging system.

METHODS

Tumors were classified in accordance with the 2015 WHO classification of lung carcinomas. The cribriform pattern was defined by invasive back-to-back fused tumor glands with poorly formed glandular spaces or invasive tumor nests of tumors cells that produce glandular lumina. Recurrence-free probability (RFP) and overall survival (OS) was analyzed using the log-rank test and the Cox proportional hazards model.

RESULTS

After the addition of the cribriform pattern, 54 of 90 acinar-predominant tumors were reclassified as cribriform subtype. Five-year RFP for patients with the cribriform subtype (51%) was lower than it was for patients with acinar and papillary subtype (81% and 80%, respectively) but was comparable to that for patients with solid subtype (48%). Five-year OS for patients with the cribriform subtype (49%) was lower than it was for patients with acinar and papillary subtype (90% and 81%, respectively). On multivariate analysis adjusted for the eighth edition of the TNM staging system, the cribriform subtype was an independent prognostic factor of a worse RFP and OS.

CONCLUSIONS

We have validated that the cribriform subtype is an independent factor of poor prognosis in patients with resected lung adenocarcinoma.