Distinctive histopathological features of lepidic growth predominant node-negative adenocarcinomas 3-5 cm in size

Novel Insights Into the International Association for the Study of Lung Cancer Grading System for Lung Adenocarcinoma

The new grading system for lung adenocarcinoma proposed by the International Association for the Study of Lung Cancer (IASLC) defines prognostic subgroups on the basis of histologic patterns observed on surgical specimens. This study sought to provide novel insights into the IASLC grading system, with particular focus on recurrence-specific survival (RSS) and lung cancer-specific survival among patients with stage I adenocarcinoma. Under the IASLC grading system, tumors were classified as grade 1 (lepidic predominant with <20% high-grade patterns [micropapillary, solid, and complex glandular]), grade 2 (acinar or papillary predominant with <20% high-grade patterns), or grade 3 (≥20% high-grade patterns). Kaplan-Meier survival estimates, pathologic features, and genomic profiles were investigated for patients whose disease was reclassified into a higher grade under the IASLC grading system on the basis of the hypothesis that they would strongly resemble patients with predominant high-grade tumors. Overall, 423 (29%) of 1443 patients with grade 1 or 2 tumors classified based on the predominant pattern-based grading system had their tumors upgraded to grade 3 based on the IASLC grading system. The RSS curves for patients with upgraded tumors were significantly different from those for patients with grade 1 or 2 tumors (log-rank P < .001) but not from those for patients with predominant high-grade patterns (P = .3). Patients with upgraded tumors had a similar incidence of visceral pleural invasion and spread of tumor through air spaces as patients with predominant high-grade patterns. In multivariable models, the IASLC grading system remained significantly associated with RSS and lung cancer-specific survival after adjustment for aggressive pathologic features such as visceral pleural invasion and spread of tumor through air spaces. The IASLC grading system outperforms the predominant pattern-based grading system and appropriately reclassifies tumors into higher grades with worse prognosis, even after other pathologic features of aggressiveness are considered.

An effective inflation treatment for frozen section diagnosis of small-sized lesions of the lung

Background

The accuracy of intraoperative pathological diagnosis of small-sized pulmonary nodules including ground-glass opacity (GGO) is important for the surgeon to choose a suitable surgical procedure. Diagnosis of the small-sized lesions of the lung by frozen section (FS) is very difficult for the pathologist because of limited FS technology. Here we tested an effective inflation treatment for FS to improve the diagnostic accuracy of small-sized lung lesions.

Methods

The lung specimens were derived from 113 patients who underwent the surgery at Shanghai Chest Hospital in 2018–2019. The specimens were randomly divided into two groups—uninflated or inflated with diluted embedding medium (Tissue-Tek OCT; Sakura Finetek-USA, CA). The qualities of the FSs were compared with that of corresponding permanent paraffin sections. The FS diagnoses were compared with the final pathologic diagnoses of corresponding permanent sections.

Results

Our results showed that the quality of FS of lung tissue was excellent after inflation with diluted embedding medium (1:1). The total consistency between diagnosis of inflated FS and final pathological diagnosis was 85.7%. In control group, however, the consistency was only 70.2%. When the lesions were less than 1cm, the consistency between diagnosis of inflated FS and final pathological diagnosis was 90.3%, compared to 64.9% consistency in uninflated group (P=0.014, <0.05). When the lesions’ computed tomography (CT) measurement threshold ≤−350 HU, the consistency between diagnosis of inflated FS and final pathological diagnosis was 88% compared to 73.2% consistency in uninflated group (P=0.071, >0.05). Accuracy, sensitivity and specificity were observed about 90% for adenocarcinoma in situ (AIS), whereas it is drop to more than 80% for minimally invasive adenocarcinoma (MIA) in inflated FS.

Conclusions

Inflation with diluted embedding medium (1:1) could make lung tissue expand well during FS. By using this method, small-sized lesions (especially less than 1 cm) could be correctly diagnosed to enable adequate surgical procedure, and evaluation of which can be easily based on the intraoperative pathological diagnosis. The small lesions especially AIS could be readily identified on FS. Therefore, this method improves the diagnostic accuracy of FSs for small-sized lung lesions, and has important practical consequences for further therapy.

Multivariate Analysis Of The Diagnostic Yield Of Conventional Bronchoscopy In Peripheral Lung Adenocarcinoma

Background

The new subtypes of lung adenocarcinoma reflect local invasive growth, pulmonary alveoli, and intraluminal spreading, while the effective improvement of the diagnostic yield of bronchoscopy still remains unclear. This study aims to explore whether the subtypes of lung adenocarcinoma and other factors affect the diagnostic yield of bronchoscopy.

Methods

All patients were performed 64-row CT examination and bronchoscopy.

Results

The bronchus cutoff sign in 48 cases and the endoscopic diagnostic yield was 60.4%. The lumen of the lobes and segments was invaded in 59 cases, and the endoscopic diagnostic yield was 54.2%.The lymph node metastasis was detected in 46 cases, and the endoscopic diagnostic yield was 60.9%. In addition, 42 cases showed acinar type-predominant, and the endoscopic diagnostic yield was 28.6%. Eighteen cases showed solid type-predominant, and the endoscopic diagnostic yield was 33.3%. The micropapillary type-predominant was noted in 17 cases, with the endoscopic diagnostic yield as 94.1%. The papillary type-predominant was in 14 cases, and the endoscopic diagnostic yield was 42.9%. The lepidic type-predominant was seen in 13 cases, and the endoscopic diagnostic yield was 7.7%. The mean diameter of tumors with a positive endoscopic diagnostic yield was 4.34±2.65cm, and the mean diameter of tumors with a negative diagnostic yield was 2.83±1.47cm. Multivariate analysis showed that micropapillary lung adenocarcinoma affected the endoscopic diagnostic yield (OR=37.594, 95% CI: 4.074-346.94) .Tumor diameter affects endoscopic diagnostic yield (OR=1.39, 95% CI: 1.073-1.802), bronchus cutoff sign is easy to obtain endoscopic diagnostic yield (OR=4.86, 95% CI: 1.606-14.704), and lymph node metastasis affects the endoscopic diagnostic yield (OR=3.696, 95% CI: 1.255-10.883).

Conclusion

The micropapillary subtype lung adenocarcinoma has a certain influence on the diagnostic yield of bronchoscopy. When the lung adenocarcinoma has a large tumor diameter, bronchus cutoff sign and lymph node metastasis, it is easy to obtain a diagnostic yield of bronchoscopy.

Challenges for real-time intraoperative diagnosis of high risk histology in lung adenocarcinoma: A necessity for sublobar resection

Recently, the incidence of small, peripheral lung adenocarcinoma has been increasing as lung cancer screening with radiologic examination is more widely performed. Tumor size is one of the determinants of the prognostic outcome in clinically node-negative lung adenocarcinoma. Sublobar resection has been proposed as one of the minimally invasive surgical options for small-sized adenocarcinomas. Despite the lack of robust clinical trial evidence, sublobar resection has become more popular, especially in developed countries where less extensive surgery may be of benefit in a population where the age of the elderly is growing. However, high risk histologic features such as micropapillary subtype and tumor spread through air space (STAS) have been associated with a significantly higher risk of local recurrence after sublobar resection, but not after lobectomy. Surgical decision-making based on frozen section diagnosis of high risk histologic features may be useful to prevent local control failure after sublobar resection. At the present time, there is little evidence to demonstrate the diagnostic accuracy of identifying high risk histologic features on frozen section. One study has so far demonstrated that diagnostic accuracy of identifying STAS is higher than that of identifying the micropapillary subtype. Additionally, the presence of STAS has been found to be more strongly associated with local recurrence in patients who had undergone sublobar resection. Although further investigation is required for validation of this finding, STAS diagnosis on frozen section may shed further light on intraoperative surgical decision-making during sublobar resection. To this end, we review the recently published data on the intraoperative identification of high risk features.

Risk factors associated with an increase in the size of ground-glass lung nodules on chest computed tomography

BACKGROUND

The detection rate of ground-glass nodules (GGNs) in the lung has increased with the increased use of low-dose computed tomography (CT) of the chest for cancer screening; however, limited data is available on the natural history, follow-up, and treatment of GGNs. The aim of this study was to identify factors associated with an increase in the size of GGNs.

METHODS

A total of 338 patients (mean ages, 59.8 years; males, 35.5%) with 689 nodules who underwent chest CT at our institute between June 2004 and February 2014 were included in this study. The cut-off date of follow-up was August 2018. We analyzed the size, solidity, number, and margins of the nodules compared with their appearance on previous chest CT images. The Cox proportional hazard model was used to identify risk factors associated with nodule growth.

RESULTS

The median follow-up period was 21.8 months. Of the 338 patients, 38.5% had a history of malignancy, including lung cancer (8.9%). Among the 689 nodules, the median size of the lesions was 6.0 mm (IQR, 5-8 mm), and the proportion of nodules with size ≥10 mm and multiplicity was 17.1% and 66.3%, respectively. Compared to the nodules without an increase in size, the 79 nodules with an increase in size during the follow-up period were initially larger (growth group, 7.0 mm vs. non-growth group, 6.0 mm; P = 0.027), more likely to have a size ≥10 mm (26.6% vs. 15.9%; P = 0.018), and had less frequent multiplicity (54.4% vs. 67.9%, P = 0.028). In the multivariate analysis, nodule size ≥10 mm (hazard ratio [HR], 2.044; P = 0.005), a patient history of lung cancer (HR: 2.190, P = 0.006), and solitary nodule (HR: 2.499, P < 0.001) were independent risk factors for nodule growth.

CONCLUSION

Careful follow-up of GGNs is warranted in patients with a history of malignancy, a large , or a solitary nodule.

Looking for Lepidic Component inside Invasive Adenocarcinomas Appearing as CT Solid Solitary Pulmonary Nodules (SPNs): CT Morpho-Densitometric Features and 18-FDG PET Findings

Objective

To investigate CT morphologic and densitometric features and 18-FDG PET findings of surgically excised lung adenocarcinomas "mixed subtype" with predominant lepidic component, appearing as solid solitary pulmonary nodules (SPNs) on CT scan.

Materials and Methods

Approval for this study was given from each local institutional review board according to its retrospective nature. Nodules pathologically classified as lung adenocarcinoma mixed subtype with bronchioloalveolar otherwise lepidic predominant component, in three different Italian institutions (Napoli; Varese; Parma), were retrospectively selected.

Results

22 patients were identified. The number of SPNs with smooth margins was significantly lower with respect to the number of SPNs with spiculated margins (p: 0.033), radiating spiculations (p: 0.019), and notch sign (p: 0.011). Mean contrast enhancement (CE) was 53.34 HU (min 5.5 HU, max 112 HU); considering 15 HU as cut-off value, CE was positive in 20/22 cases. No significant correlation was found between size and CE. Mean SUVmax was 2.21, ranging from 0.2 up to 7.5 units; considering 2.5 units as cut-off, SUVmax was positive in 7/22 cases. The number of SPNs with positive CE was significantly higher than the number of SPNs with positive SUVmax (p: 0.0005).

Conclusion

CT generally helps in identifying solid SPN suspicious for malignancy but 18-FDG PET may result in false-negative evaluation; when 18-FDG PET findings of a solid SPN are negative even though CT morphology and CE suggest malignancy, radiologist should consider that lepidic component may be present inside the invasive tumor, despite the absence of ground glass.

Histologic subtyping in pathologic stage I-IIA lung adenocarcinoma provides risk-based stratification for surveillance

Background

We hypothesize that recurrence hazard following resection for stage I-IIA lung adenocarcinoma (ADC) varies according to histologic subtype, which may provide risk stratification for surveillance better than the current uniform follow-up protocol.

Results

Presence (≥5%) of high-grade histologic subtypes (MIP and/or SOL) was associated with a significantly higher recurrence hazard: (1) presence of either MIP or SOL was associated with a significant increase in recurrence hazard during the first two years after surgery; (2) presence of SOL was associated with an increase in recurrence hazard—in particular, distant recurrence hazard—during the first year after surgery; (3) absence of high-grade subtypes (515/1,572 patients) was associated with a very low recurrence hazard (<2% risk/year) during the first ten years after surgery.

Methods

All hematoxylin and eosin–stained tumor slides from pathologic stage I-IIA lung ADC (n = 1572) were reviewed for quantification of the percentage of each histological subtype. Recurrence hazard was estimated using the Kernel-Epanechnikov smoothing procedure. The association between recurrence hazard and high-grade histologic subtypes (micropapillary [MIP] and solid [SOL]) was assessed.

Conclusions

Our findings suggest that histologic subtyping has utility for identifying recurrence hazard for surgically resected stage I-IIA lung ADC patients and provide rationale for establishing risk-based surveillance.

Size of Non-lepidic Invasive Pattern Predicts Recurrence in Pulmonary Mucinous Adenocarcinoma: Morphologic Analysis of 188 Resected Cases with Reappraisal of Invasion Criteria

Background

We reviewed a series of 188 resected pulmonary mucinous adenocarcinomas (MAs) to clarify the prognostic significance of lepidic and non-lepidic patterns.

Methods

Non-lepidic patterns were divided into bland, non-distorted acini with uncertain invasiveness (pattern 1), unequivocal invasion into stroma (pattern 2), or invasion into alveolar spaces (pattern 3).

Results

The mean proportion of invasive patterns (patterns 2 and 3) was lowest in small (≤ 3 cm) tumors, and gradually increased in intermediate (> 3 cm and ≤ 7 cm) and large (> 7 cm) tumors (8.4%, 34.3%, and 50.1%, respectively). Adjusted T (aT) stage, as determined by the size of invasive patterns, was positively correlated with adverse histologic and clinical features including older age, male sex, and ever smokers. aTis tumors, which were exclusively composed of lepidic pattern (n = 9), or a mixture of lepidic and pattern 1 (n = 40) without any invasive patterns, showed 100% disease- free survival (DFS). The aT1mi tumors, with minimal (≤ 5 mm) invasive patterns (n = 63), showed a 95.2% 5-year DFS, with recurrences (n = 2) limited to tumors greater than 3 cm in total size (n = 23). Both T and aT stage were significantly associated with DFS; however, survival within the separate T-stage subgroups was stratified according to the aT stage, most notably in the intermediatestage subgroups. In multivariate analysis, the size of invasive patterns (p = .020), pleural invasion (p < .001), and vascular invasion (p = .048) were independent predictors of recurrence, whereas total size failed to achieve statistical significance (p = .121).

Conclusions

This study provides a rationale for histologic risk stratification in pulmonary MA based on the extent of invasive growth patterns with refined criteria for invasion.

Histologic Subtype in Core Lung Biopsies of Early-Stage Lung Adenocarcinoma is a Prognostic Factor for Treatment Response and Failure Patterns After Stereotactic Body Radiation Therapy

PURPOSE

Stereotactic body radiation therapy (SBRT) has emerged as an effective treatment for early-stage lung cancer. The histologic subtype of surgically resected lung adenocarcinoma is recognized as a prognostic factor, with the presence of solid or micropapillary patterns predicting poor outcomes. We describe the outcomes after SBRT for early-stage lung adenocarcinoma stratified by histologic subtype.

METHODS AND MATERIALS

We identified 119 consecutive patients (124 lesions) with stage I to IIA lung adenocarcinoma who had undergone definitive SBRT at our institution from August 2008 to August 2015 and had undergone core biopsy. Histologic subtyping was performed according to the 2015 World Health Organization classification. Of the 124 tumors, 37 (30%) were a high-risk subtype, defined as containing a component of solid and/or micropapillary pattern. The cumulative incidences of local, nodal, regional, and distant failure were compared between the high-risk and non-high-risk adenocarcinoma subtypes using Gray's test, and multivariable-adjusted hazard ratios (HRs) were estimated from propensity score-weighted Cox regression models.

RESULTS

The median follow-up for the entire cohort was 17 months and for surviving patients was 21 months. The 1-year cumulative incidence of and adjusted HR for local, nodal, regional, and distant failure in high-risk versus non-high-risk lesions was 7.3% versus 2.7% (HR 16.8; 95% confidence interval [CI] 3.5-81.4), 14.8% versus 2.6% (HR 3.8; 95% CI 0.95-15.0), 4.0% versus 1.2% (HR 20.9; 95% CI 2.3-192.3), and 22.7% versus 3.6% (HR 6.9; 95% CI 2.2-21.1), respectively. No significant difference was seen with regard to overall survival.

CONCLUSIONS

The outcomes after SBRT for early-stage adenocarcinoma of the lung correlate highly with histologic subtype, with micropapillary and solid tumors portending significantly higher rates of locoregional and metastatic progression. In this context, the histologic subtype determined from core biopsies is a prognostic factor and could have important implications for patient selection, adjuvant treatment, biopsy methods, and clinical trial design.

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, integrinβ1, 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.

The percentage of lepidic growth is an independent prognostic factor in invasive adenocarcinoma of the lung

Background

The literature is inconclusive as to whether the percentage of the lepidic component of an invasive adenocarcinoma (AC) of the lung influences prognosis. We studied a population-based series of selected, resected invasive pulmonary ACs to determine if incremental increases in the lepidic component were an independent, prognostic variable.

Methods

Patients undergoing resection for lung cancer reported to the Cancer Registry of Norway and diagnosed in the period 1993-2002 with a bronchioloalveolar carcinoma (BAC) (old terminology) (adenocarcinoma in situ, AIS in the new terminology) in the lung were selected. A pulmonary pathologist reviewed all sections and estimated the percentage of the lepidic component. Follow-up of survival was to the end of 2013.

Results

One hundred thirty-one patients were identified, 102 had AC with lepidic growth. Of these, 44 had AC with a component of lepidic growth less than 50 % and seven had AC with 95 % lepidic component or more. One of the latter cases was considered to be AIS. In regression analyses, superior survival was associated with a greater lepidic component (p = 0.041). Mucinous tumors had a worse prognosis than non-mucinous (p = 0.012) in regression analyses, as did increasing age and stage. The five-year observed survival was 69.0 % for non-mucinous cases and 66.7 % for the group with a lepidic component of 80 % or greater.

Conclusion

The percentage of the lepidic component appears to be an independent, significant prognostic factor in a selection of pulmonary AC.

Significant correlation between urinary N(1), N(12)-diacetylspermine and tumor invasiveness in patients with clinical stage IA non-small cell lung cancer

Background

To select optimal candidates for limited lung resection, it is necessary to accurately differentiate the non-invasive tumors from other small-sized lung cancer. Urinary N¹, N¹²-diacetylspermine (DiAcSpm) has been reported to be a useful tumor marker for various cancers. We aimed to examine the correlation between preoperative urinary DiAcSpm levels and specific clinicopathological characteristics such as the histological tumor invasiveness in patients with clinical stage IA non-small cell lung cancer (NSCLC).

Methods

We defined non-invasive tumors as NSCLC showing no vascular invasion, lymphatic permeation, pleural invasion, or lymph node metastasis. Preoperative urine samples were obtained from 516 consecutive patients with NSCLC resected at our institution between April 2008 and January 2013. Urinary DiAcSpm values were determined for all preoperative urine samples using the colloid gold aggregation procedure. Among these patients, 171 patients with clinical stage IA NSCLC met the criteria of our study cohort. Finally, we investigated the correlation between non-invasive tumor and urinary DiAcSpm levels.

Results

The median urine DiAcSpm for males was 147.2 nmol/g creatinine and 161.8 nmol/g creatinine in females. These median values were set as the cut-off values for each gender. Patients with higher urinary DiAcSpm levels frequently had significantly elevated serum CEA (p = 0.023) and greater lymph node metastasis (p = 0.048), lymphatic permeation (p = 0.046), and vascular invasion (p = 0.010). Compared with patients with non-invasive tumors, patients with invasive tumors had a tumor size >2.0 cm (p = 0.001), serum CEA >5.0 mg/dL (p < 0.001), high urinary DiAcSpm (p = 0.002), and a tumor disappearance rate (TDR) <0.75 (p < 0.001). Multivariate analysis revealed that a tumor size < 2.0 cm (RR = 2.901, 95% CI; 1.372-6.136, p = 0.005), high urinary DiAcSpm (RR = 3.374, 95% CI; 1.547-7.361, p = 0.002), and TDR < 0.75 (RR = 4.673, 95% CI; 2.178-10.027, p < 0.001) were independent predictors for invasive tumors.

Conclusions

We successfully showed that there was a significant correlation between urinary DiAcSpm levels and pathological tumor invasiveness in patients with clinical stage IA NSCLC. Further research would elucidate the clinical usefulness of DiAcSpm levels as a predictor of tumor invasiveness.

Electronic supplementary material

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