The accuracy of frozen section diagnosis of pulmonary nodules: evaluation of inflation method during intraoperative pathology consultation with cryosection

Improving intraoperative diagnosis of spread through air spaces: A cryo-embedding-medium inflation method for frozen section analysis

Objective

Accurate intraoperative diagnosis of spread through air spaces (STAS), a known poor prognostic factor in lung cancer, is crucial for guiding surgical decision-making during sublobar resections. This study aimed to evaluate the diagnostic sensitivity of STAS using frozen section (FS) slides prepared with the cryo-embedding medium inflation technique.

Methods

In this prospective study at Shinshu University Hospital, 99 patients undergoing lung resection for tumors <3 cm in size were included, a total of 114 lesions. FS slides were prepared with injecting diluted cryo-embedding medium into the lung parenchyma of resected specimens. The diagnostic performance of these FS slides for STAS detection was evaluated by comparing FS-STAS results with the gold-standard STAS status.

Results

The incidence of STAS, determined by the gold standard, was 43 (38%) of 114 lesions, including 31 (37%) of 84 primary lung cancers and 12 (40%) of 30 metastatic lung tumors. The sensitivity, specificity, positive and negative predictive values, and accuracy of FS slides for STAS detection were 81%, 89%, 81%, 89%, and 86%, respectively. Specifically, in primary lung cancers, these values were 90%, 89%, 82%, 94%, and 89%, respectively. Regarding metastatic lung tumors, the corresponding values were 58%, 89%, 78%, 76%, and 77%, respectively.

Conclusions

Our adapted cryo-embedding medium inflation method has demonstrated enhanced sensitivity in detecting STAS on FS slides, providing results similar to the gold-standard STAS detection. Compared with historical benchmarks, this technique could show excellent performance and be readily incorporated into clinical practice without requiring additional resources beyond those used for standard FS analysis.

Sub-lobar resection versus lobectomy for challenging intraoperative frozen sections in lung adenocarcinoma within 3 cm

OBJECTIVES

Intraoperative frozen section (FS) analysis is pivotal in guiding surgical interventions for early-stage lung adenocarcinoma. However, the challenge arises when distinguishing between Minimally Invasive Adenocarcinoma (MIA) and Invasive Adenocarcinoma (IAC) poses diagnostic difficulties. This study investigates the prognosis and clinicopathological characteristics of patients encountering this diagnostic challenge.

METHODS

We conducted a retrospective analysis of 7082 intraoperative FSs from early-stage lung adenocarcinoma cases. The cases with pulmonary nodules within 3 cm and diagnosed as indeterminate FSs were included. We analyzed baseline data, computed tomography (CT) findings, and pathological characteristics. Prognostic data were obtained from patients with confirmed IAC diagnoses through final pathological examination.

RESULTS

Out of 7082 FSs, 551 cases presented challenges in distinguishing between MIA and IAC. Upon final pathological examination, 233 cases were identified as IAC, while 314 were classified as MIA. The median invasive pathological size in the IAC group was larger than that in the MIA group (0.6 cm vs 0.3 cm). 131 cases (56.2 %) with IAC underwent lobectomy, while 102 cases (43.8 %) underwent sub-lobar resection. Among the MIA cases, 220 cases (69.8 %) underwent sub-lobar resection, while 95 cases (30.2 %) underwent lobectomy. No recurrence and disease specific death was observed during the follow-up period, regardless of surgical strategy.

CONCLUSIONS

Indeterminate intraoperative FSs, posing diagnostic challenges in distinguishing between MIA and IAC. Sub-lobar resection presented the same long term survival benefit compared with the lobectomy for indeterminate lung adenocarcinoma within 3 cm during intraoperative FSs.

Optimal resection strategies for small-size lung cancer: Is a wedge enough? Is lobectomy too much?

Recently published large multicenter prospective clinical trials have demonstrated that sublobar resection is noninferior to lobectomy, the traditional treatment of choice, for peripherally located early-stage lung cancer. Most clinical trials and several retrospective studies published to date have used the consolidation-to-tumor ratio to define the indication for sublobar resection, as it is well known that the size of the solid portion seen on high-resolution computed tomography is highly correlated with pathologic invasiveness. However, it is difficult to accurately predict pathologic features that may increase the risk of locoregional recurrence, such as specific adenocarcinoma subtypes or spread through air spaces, based on imaging characteristics alone, and the location of the nodule also should be considered one of the important factors in obtaining an adequate parenchymal resection margin. In this article, we summarize the results of the most recently published clinical trials related to sublobar resection and discuss various factors that should be considered for optimal candidate selection for sublobar resection.

Rapid On-Site AI-Assisted Grading for Lung Surgery Based on Optical Coherence Tomography

The determination of resection extent traditionally relies on the microscopic invasiveness of frozen sections (FSs) and is crucial for surgery of early lung cancer with preoperatively unknown histology. While previous research has shown the value of optical coherence tomography (OCT) for instant lung cancer diagnosis, tumor grading through OCT remains challenging. Therefore, this study proposes an interactive human-machine interface (HMI) that integrates a mobile OCT system, deep learning algorithms, and attention mechanisms. The system is designed to mark the lesion's location on the image smartly and perform tumor grading in real time, potentially facilitating clinical decision making. Twelve patients with a preoperatively unknown tumor but a final diagnosis of adenocarcinoma underwent thoracoscopic resection, and the artificial intelligence (AI)-designed system mentioned above was used to measure fresh specimens. Results were compared to FSs benchmarked on permanent pathologic reports. Current results show better differentiating power among minimally invasive adenocarcinoma (MIA), invasive adenocarcinoma (IA), and normal tissue, with an overall accuracy of 84.9%, compared to 20% for FSs. Additionally, the sensitivity and specificity, the sensitivity and specificity were 89% and 82.7% for MIA and 94% and 80.6% for IA, respectively. The results suggest that this AI system can potentially produce rapid and efficient diagnoses and ultimately improve patient outcomes.

Diagnostic value of intraoperative fine-needle aspiration cytologic diagnosis versus frozen section-based histopathologic diagnosis in thoracic malignancies: A single institution's experience

BACKGROUND

Primary lung cancer is the leading cause of cancer death in the United States. Most lung cancers are diagnosed in an outpatient setting, but a subset requires intraoperative diagnosis. Two intraoperative diagnostic methods are available, frozen section (FS) and fine needle aspiration (FNA) cytology. This study compares intraoperative FNA cytology and FS based diagnosis in thoracic malignancies within the same clinical practice.

METHODS

Pathology reports from thoracic intraoperative FNA cytology or FS (January 2017-December 2019) were reviewed. Resection diagnosis was the gold standard. If unavailable, concurrent biopsy and final FNA cytology diagnosis were the gold standard.

RESULTS

Of 300 FNA specimens (155 patients), 142 (47%) cases were benign, and 158 (53%) were malignant. Adenocarcinoma was the most common malignant diagnosis (40%), followed by squamous cell carcinoma (26%), neuroendocrine tumors (18%), and other (16%). Intraoperative FNA yielded 88% sensitivity, 99% specificity, and 92% accuracy (p < .001). Of 298 FS specimens (252 patients), 215 (72%) cases were malignant and 83 (28%) were benign. Adenocarcinomas was the most common malignant diagnosis (48%), followed by squamous cell carcinoma (25%), metastatic carcinomas (13%), and other (14%). FS yielded 97% sensitivity, 99% specificity, and 97% accuracy (p < .001).

CONCLUSION

Our findings confirm FS is the gold standard for intraoperative diagnosis. FNA cytology may be useful as a non-invasive, inexpensive initial diagnostic tool intraoperatively, given the similar specificity (99% FNA, 99% FS) and accuracy (92% FNA, 97% FS). Negative FNA could be followed by the costlier and invasive FS. We encourage surgeons to utilize intraoperative FNA first.

Intraoperative application of optical coherence tomography for lung tumor

On-site instant determination of benign or malignant tumors for deciding the types of resection is crucial during pulmonary surgery. We designed a portable spectral-domain optical coherence tomography (SD-OCT) system to do real-time scanning intraoperatively for the distinction of fresh tumor specimens in the lung. A total of 12 ex vivo lung specimens from six patients were enrolled. Three patients were diagnosed with invasive adenocarcinoma (IA), while the others were benign. After OCT-imaged reconstruction, we compared the qualitative morphology of OCT and histology among malignant, benign, and normal tissues. In addition, through analysis of the quantitative data, a discrete difference in optical attenuation coefficients around the junctional surface was shown by our data processing. This study demonstrated a feasible OCT-assisted resection guide by a rapid on-site tumor diagnosis. The results indicate that future deep learning of OCT-captured image systems able to improve diagnostic and therapeutic efficiency is warranted.

Could cytology supplant frozen section for intraoperative evaluation of thoracic lesions? A single institutional experience in a developing country

BACKGROUND

The diagnostic performance of cytology was compared with the frozen results and its usability was evaluated as a rapid diagnosis method in intraoperative thoracic surgery in a single institution (Istanbul, Turkey).

METHODS

All 197 subsequent patient specimens (cases) from 158 patients who were sent to our department from the thoracic surgery clinic for an intraoperative diagnosis request between the years 2016 and 2021 were evaluated. Obtained results from frozen and cytology were compared with final paraffin section diagnoses. Lesions were grouped into three different groups as nonneoplastic, benign, and malignant neoplasms.

RESULTS

Diagnostic accuracy values of cytology and frozen sections in intraoperative consultation were 98.8% and 99.4%, respectively. Sensitivity values of cytology and frozen sections in intraoperative consultation were 96.3% and 98.7%, respectively. Specificity values of cytology and frozen sections in intraoperative consultation were 100% and 100%, respectively. Negative predictive values of cytology and frozen sections in intraoperative consultation were 96.7% and 98.9%, respectively. Positive predictive values of cytology and frozen sections in intraoperative consultation were 100% and 100%, respectively. Kappa statistics between cytology and frozen revealed a very high interrater reliability (Cohen's Kappa value: 0.911; p = .001; p < .01). The difficulty in distinguishing primary and metastatic carcinoma, which is mostly undecided in frozen sections and the definitive diagnosis is left to paraffin sections, seems also be a problem in the cytological examination.

CONCLUSIONS

Cytological diagnosis can be used in the evaluation of small biopsy specimens that require tissue preservation in intraoperative consultation, especially for immunohistochemical and advanced genetic studies.

Intraoperative rapid immunohistochemistry with noncontact antibody mixing for undiagnosed pulmonary tumors

Knowledge of the histologic type and primary origin of pulmonary tumors is essential when preparing a surgical strategy. Intraoperative diagnosis of hematoxylin and eosin (H&E)-stained frozen sections is the gold standard, but reliable pathology requires time-consuming immunohistochemistry (IHC) to distinguish among histological types/organ origins and to analyze molecular status. The aim of this study was to evaluate the clinical reliability of a new rapid-IHC technique for intraoperative diagnosis of pulmonary tumors. In total, 169 patients with undiagnosed pulmonary tumors were enrolled in a multicenter prospective observational study. At three institutes, pulmonary tumor samples were collected through core needle biopsy and/or surgery to determine surgical strategies. Using a new device for rapid IHC, we applied a high-voltage, low-frequency alternating current (AC) field, which mixes the available antibody as the voltage is switched on/off. Rapid IHC can provide tumor histologic type/origin diagnoses within 20 min, as opposed to the 3-6 h required for conventional IHC. No false diagnoses of malignancy were rendered in any of the cases when using simple H&E staining. With H&E staining alone, the overall definitive diagnosis rate, the rate of defined tumor origin, and the rate of determined histological type were 76.92%, 85.80%, and 90.53%, respectively. When rapid IHC was added, those rates were significantly improved to 88.76%, 94.67%, and 91.72%, respectively. By providing prompt and accurate intraoperative histological/molecular analysis, rapid IHC driven by AC mixing could serve as an effective clinical tool guiding the surgical strategy for undiagnosed pulmonary tumors.

A random forest algorithm predicting model combining intraoperative frozen section analysis and clinical features guides surgical strategy for peripheral solitary pulmonary nodules

Background

Intraoperative frozen section (FS) analysis has been used to guide the extent of resection in patients with solitary pulmonary nodules (SPNs), but its accuracy varies greatly among different hospitals. Artificial intelligence (AI) and multidimensional data technology are developing rapidly these years, meanwhile, surgeons need better methods to guide the surgical strategy of SPNs. We established predicting models combining FS results with multidimensional perioperative clinical features using logistic regression analysis and the random forest (RF) algorithm to get more accurate extent of SPN resection.

Methods

Patients with peripheral SPNs who underwent FS-guided surgical resection at the Shanghai Chest Hospital (January 2017-December 2018) were retrospectively examined (N=3,089). The accuracy of intraoperative FS-guided resection extent was analyzed and used as Model 1. The clinical features (sex, age, CT features, tumor markers, smoking history, lesion size and nodule location) of patients were collected, and Models 2 and 3 were established using logistic regression and RF algorithms to combine the FS with clinical features. We confirmed the performance of these models in an external validation cohort of 117 patients from Hwa Mei Hospital, University of Chinese Academy of Science (Ningbo No. 2 Hospital). We compared the effectiveness in classifying low/high-risk groups of SPN among them.

Results

The accuracy of FS analysis was 61.3%. Model 3 exhibited the best diagnostic accuracy and had an area under the curve of 0.903 in n the internal validation cohort and 0.919 in the external validation cohort. The calibration plots and net reclassification index (NRI) of Model 3 also exhibited significantly better performance than the other models. Improved diagnostic accuracy was observed in in both internal and external validation cohort.

Conclusions

Using an RF algorithm, clinical characteristics can be combined with intraoperative FS analysis to significantly improve intraoperative judgment accuracy for low- and high-risk tumors, and may serve as a reliable complementary method when FS evaluation is equivocal, improving the accuracy of the extent of surgical resection.

Postoperative computed tomography of insufflated lung specimens obtained by video-assisted thoracic surgery: detection and margin assessment of pulmonary nodules

Objective

To investigate the utility of computed tomography (CT) scans to detect and assess the margin status of pulmonary nodules that were insufflated after being resected by video-assisted thoracic surgery.

Materials and Methods

This was a novel multicenter study conducted at two national referral centers for thoracic diseases. Patients suspected of having lung cancer underwent video-assisted thoracic surgery for the resection of pulmonary nodules, which were submitted to postoperative CT. Measurements from the CT scans were compared with the results of the histopathological analysis.

Results

A total of 37 pulmonary nodules from 37 patients were evaluated. The mean age of the patients was 65 years (range, 36-84 years), and 27 (73%) were female. A CT analysis of insufflated specimens identified all 37 nodules, and 33 of those nodules were found to have tumor-free margins. The histopathological analysis revealed lung cancer in 30 of the nodules, all with tumor-free margins, and benign lesions in the seven remaining nodules.

Conclusion

Postoperative CT of insufflated suspicious lung lesions provides real-time detection of pulmonary nodules and satisfactory assessment of tumor margins. This initial study shows that CT of insufflated lung lesions can be a valuable tool at centers where intraoperative histopathological analysis is unavailable.

Management of Ground-Glass Nodules: When and How to Operate?

Simple Summary

An increasing number of lung cancer screening programs have detected the frequent occurrence of small pulmonary ground-glass nodules (GGNs). If GGN is an incidental finding, it should be followed according to the guidelines. A multidisciplinary team discussion should be initiated if a new solid component develops or the solid portion grows on follow-up CT. Preoperative attempts to biopsy solid components in part-solid GGNs are often not feasible and not helpful. If malignancy is suspected, a surgical biopsy with the guidance of various localization methods is recommended. Once the GGN is confirmed to be malignant, sub-lobar resection may be reasonable in the majority of cases, and the extent of lung resection should be determined based on the CT finding or intraoperative frozen section examination using special inflation technique. Although rare, the recurrence in the remaining lobe can occur especially in patients with high risk histologic features, which currently cannot accurately diagnosed either pre- or intra-operatively.

Abstract

With the increased popularity of low-dose computed tomography (LDCT), many patients present with pulmonary ground-glass nodules (GGNs), and the appropriate diagnostic and management strategy of those lesions make physicians be on the horn of the clinical dilemma. As there is not enough data available to set universally acceptable guidelines, the management of GGNs may be different. If GGN is an incidental finding through LDCT, the lesion should be followed according to the current guidelines. We recommend a multidisciplinary team discussion to be initiated if a new solid component develops or the solid portion size grows on follow-up CT as the risk of malignancy is high. Attempts to preoperatively biopsy solid components in part-solid GGNs are often not feasible and not helpful in clinical settings. Currently, if malignancy is suspected, a surgical biopsy with the guidance of various localization methods is recommended. If malignancy is confirmed, sub-lobar resection may provide an excellent oncologic outcome.

Novel Genetic Prognostic Signature for Lung Adenocarcinoma Identified by Differences in Gene Expression Profiles of Low- and High-Grade Histological Subtypes

The 2021 WHO classification proposed a pattern-based grading system for early-stage invasive non-mucinous lung adenocarcinoma. Lung adenocarcinomas with high-grade patterns have poorer outcomes than those with lepidic-predominant patterns. This study aimed to establish genetic prognostic signatures by comparing differences in gene expression profiles between low- and high-grade adenocarcinomas. Twenty-six (9 low- and 17 high-grade adenocarcinomas) patients with histologically “near-pure” patterns (predominant pattern comprising >70% of tumor areas) were selected retrospectively. Using RNA sequencing, gene expression profiles between the low- and high-grade groups were analyzed, and genes with significantly different expression levels between these two groups were selected for genetic prognostic signatures. In total, 196 significant candidate genes (164 upregulated and 32 upregulated in the high- and low-grade groups, respectively) were identified. After intersection with The Cancer Genome Atlas–Lung Adenocarcinoma prognostic genes, three genes, exonuclease 1 (EXO1), family with sequence similarity 83, member A (FAM83A), and disks large-associated protein 5 (DLGAP5), were identified as prognostic gene signatures. Two independent cohorts were used for validation, and the areas under the time-dependent receiver operating characteristic were 0.784 and 0.703 in the GSE31210 and GSE30219 cohorts, respectively. Our result showed the feasibility and accuracy of this novel three-gene prognostic signature for predicting the clinical outcomes of lung adenocarcinoma.

Validity of surgical decision based on intraoperative frozen section diagnosis for unconfirmed pulmonary nodules with previous malignancy

OBJECTIVES

The lung is a major target organ of metastasis in several cancers. To distinguish primary lung cancer from pulmonary metastases is a clinical challenge. Small pulmonary nodules (PNs) are frequently diagnosed by frozen section diagnosis (FSD) intraoperatively after resection. Intraoperative FSD is very important to determine the extent of subsequent surgical procedures. This study aimed to know the validity of surgical decision based on FSD for preoperatively unconfirmed PN with previous malignancy.

METHODS

We retrospectively evaluated 96 patients with suspected malignant PN who underwent intraoperative FSD between 2018 and 2020. Intraoperative FSD, final diagnosis, and surgical procedure data were examined.

RESULTS

Surgical procedure adequacy, based on FSD for preoperatively unconfirmed PN with previous malignancy, was 91% (88/96). The overall diagnostic accuracy of FSD was 83.3% (80/96). Discrepancy was noted in two cases (2.1%), and conclusive diagnosis could not be reached intraoperatively in 14 cases (14.6%). A second surgery was required in three patients and no additional excision for primary lung cancer was performed in three patients. Conversely, there were three cases of over-surgery, namely, lobectomy for pulmonary metastasis.

CONCLUSIONS

Surgical decision-making based on FSD for preoperatively unconfirmed PN in patients with previous malignancy was generally adequate. However, there were inadequate or excessive surgical procedures due to limitations in the accuracy of intraoperative FSD. Improving the accuracy of intraoperative FSD is a necessary step for obtaining adequate surgical decision-making and precision medicine.

Could concurrent biopsy and microwave ablation be reliable? Concordance between frozen section examination and final pathology in CT-guided biopsy of lung cancer

PURPOSE

Microwave ablation combined with concurrent biopsy has been used for lung cancer. Frozen section (FS) diagnosis is an important supplement for the final pathology (FP). Thus, a retrospective study was conducted to evaluate the concordance between FS examination and FP in the computed tomography (CT)-guided biopsy of lung cancer.

MATERIALS AND METHODS

Patients who underwent percutaneous transthoracic needle lung biopsies and were diagnosed using both intraoperative FS examination and FP were retrospectively enrolled. Concordance between FS findings and FP in the diagnosis of malignant lung cancer and the definitive histology types were recorded.

RESULTS

Overall, 163 patients were enrolled. The concordance rate in the diagnosis of malignant tumors was 96.3%. The definitive histology types were concordant between FS examinations and FP in 112 patients (68.7%). Lung cancers undefined with FS but diagnosed as adenocarcinoma with FP were the most common type, observed in 18 patients. The concordance in the histology type was lower for those requiring immunohistochemistry for FP diagnoses (47.3 vs. 79.6%, p < 0.000). Concordance rates differed for the different histology types diagnosed using FP (adenocarcinoma vs. squamous cell carcinoma vs. small-cell lung cancer vs. others, 76.6 vs. 56.2 vs. 69.2 vs. 0.0%, p < 0.000).

CONCLUSIONS

FS was inferior to FP in the diagnosis of definitive histology types, but had a high concordance with FP in the diagnosis of malignant lung cancer.

Tumor spread through air spaces (STAS): prognostic significance of grading in non-small cell lung cancer

Tumor spread through air spaces (STAS) is an invasive pattern of lung cancer that was recently described. In this study, we investigated the association between the extent of STAS and clinicopathological characteristics and patient outcomes in resected non-small cell lung cancers (NSCLCs). STAS has been prospectively described from 2008 and graded its extent with a two-tiered system (STAS I: <2500 μm [one field of ×10 objective lens] from the edge of tumor and STAS II: ≥2500 μm from the edge of tumor) from 2011 in Seoul National University Bundang Hospital. We retrospectively analyzed the correlations between the extent of STAS and clinicopathologic characteristics and prognostic significance in 1869 resected NSCLCs. STAS was observed in 765 cases (40.9%) with 456 STAS I (24.4%) and 309 STAS II (16.5%). STAS was more frequently found in patients with adenocarcinoma (ADC) (than squamous cell carcinoma), pleural invasion, lymphovascular invasion, and/or higher pathologic stage. In ADC, there were significant differences in recurrence free survival (RFS), overall survival (OS), and lung cancer specific survival (LCSS) according to the extent of STAS. In stage IA non-mucinous ADC, multivariate analysis revealed that STAS II was significantly associated with shorter RFS and LCSS (p < 0.001 and p = 0.006, respectively). In addition, STAS II was an independent poor prognostic factor for recurrence in both limited and radical resection groups (p = 0.001 and p = 0.023, respectively). In conclusion, presence of STAS II was an independent poor prognostic factor in stage IA non-mucinous ADC regardless of the extent of resection.

Prognostic significance of tumor spread through air spaces in patients with stage IA part-solid lung adenocarcinoma after sublobar resection

OBJECTIVES

The purpose of this study was to assess the clinicopathologic implications of tumor spread through air spaces (STAS) in patients with stage IA part-solid lung adenocarcinoma after sublobar resection.

MATERIALS AND METHODS

Medical records of patients with stage IA part-solid adenocarcinoma who underwent curative pulmonary resection between February 2009 and December 2016 were retrospectively reviewed. The clinicopathological features of STAS and its influence on postoperative recurrence and survival were investigated.

RESULTS

Among the 115 patients with stage IA part-solid adenocarcinoma who underwent wedge resection, 20 (17.4 %) had STAS. The multivariable analysis showed presence of STAS [HR (hazard ratio), 9.447; p = 0.002) and a larger invasive component size (HR, 1.097; p = 0.034) were independent risk factors for recurrence. The 5-year freedom from recurrence rates were 62.4 % and 97.9 % in cases with and without STAS, respectively (p < 0.001), and the 5-year disease-free survival rates were 58.5 % and 97.9 % in cases with and without STAS, respectively (p < 0.001). The presence of STAS was associated with old age (p = 0.030), male gender (p = 0.023), acinar predominant histologic pattern (p = 0.004), presence of micropapillary pattern (p < 0.001), lymphovascular invasion (p < 0.001) and larger invasive component (p < 0.001).

CONCLUSION

STAS could be an important prognostic factor in patients with stage IA part-solid lung adenocarcinoma after sublobar resection. Effective preoperative evaluation and postoperative surveillance may help improve the outcome of patients with small part-solid nodules, particularly when accompanied by STAS.

Excellent Prognosis of Patients With Invasive Lung Adenocarcinomas During Surgery Misdiagnosed as Atypical Adenomatous Hyperplasia, Adenocarcinoma In Situ, or Minimally Invasive Adenocarcinoma by Frozen Section

BACKGROUND

Our previous study revealed that intraoperative frozen section (FS) analysis could differentiate invasive lung adenocarcinoma (LUAD) accurately from preinvasive lesions. However, few articles have analyzed the clinical impact of FS errors such as underestimation of invasive adenocarcinomas (IACs), and whether complementary therapy is needed remains controversial.

RESEARCH QUESTION

What is the prognosis of patients undergoing limited resection for invasive LUAD misdiagnosed as atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), or minimally invasive adenocarcinoma (MIA) by intraoperative FS analysis?

STUDY DESIGN AND METHODS

From 2012 through 2018, data on 3031 patients undergoing sublobar resection of AAH, AIS, or MIA diagnosed by FS analysis were collected. The concordance rate between FS analysis and final pathologic results was evaluated. To assess the clinical significance of a discrepancy between FS and final pathologic results, patients with final pathologic results of IAC were identified for prognostic evaluation.

RESULTS

When AAH, AIS, and MIA were classified together as a group, the overall concordance rate between FS and final pathologic results was 93.7%, and 192 patients (6.3%) received an upgraded diagnosis from the final pathologic results. Misdiagnosed IACs consisted of 94 patients (48.9%) with lepidic-predominant adenocarcinoma, 77 patients (40.1%) with acinar predominant adenocarcinoma, 19 patients (9.9%) with papillary predominant adenocarcinoma, one patient with solid predominant adenocarcinoma, and one patient with invasive mucinous adenocarcinoma. Among these patients, no positive N1 or N2 lymph node findings were observed. Moreover, the 5-year recurrence-free survival was still 100%, although the final pathologic results turned out to be IAC.

INTERPRETATION

Patients undergoing limited resection of invasive LUAD misdiagnosed as AAH, AIS, or MIA by FS analysis showed excellent prognoses. Sublobar resection guided by FS diagnosis would be adequate for these underestimated cases of invasive LUAD.

Analysis of Segmental Lymph Node Metastasis and Clinical Features in cT1N0M0 Lung Adenocarcinoma

The progression of lung adenocarcinoma through lymph node metastasis has been well established; however, the process of segmental lymph node (LSN) metastasis in cT1N0M0 lung adenocarcinoma remains unclear. We aimed to elucidate the markers of lymph node metastasis to different segments in early-stage lung adenocarcinoma and identify new indications for segmentectomy. A total of 200 patients were enrolled in this study. These patients were diagnosed with cT1N0M0 lung adenocarcinoma after positron emission tomography/computed tomography and received lobectomy and lymph node dissection surgeries. Lymph nodes retrieved from each station were sorted. The metastatic status of the isolated (i) LSNs and several characteristics were analyzed. Patients with ground-glass nodules (GGNs) (P=0.025), AIS/MIA/lepidic adenocarcinoma (P=0.038), nodules with a maximum diameter ≤1 cm (P=0.017), maximum standardized uptake value (SUV_max) < 2.5 (P=0.029), serum carcinoembryonic antigen (CEA) levels ≤4.5 ng/ml (P=0.036), and no N1 lymph nodes metastasis (P=0.036) had significantly lower iLSN metastasis rates than those without these characteristics. Pure GGNs, CEA levels ≤4.5 ng/ml, SUV_max < 2.5, tumors with a maximum diameter of ≤1 cm, or those confirmed to be adenocarcinoma in situ, minimally invasive adenocarcinoma, or invasive lepidic-predominant adenocarcinoma by frozen section may indicate segmentectomy. However, segmentectomy is not suitable for patients with metastasis to the N1 lymph nodes.

Long non-coding RNAs in non-small cell lung cancer: functions and distinctions from other malignancies

Lung cancer leads to the most cancer-related death in the world. It was shown from the increasing evidences that long non-coding RNAs (lncRNAs) are emerging as molecules for diagnosis, prognosis and even therapy of lung cancer and other malignancies. The biological functions or involved signaling pathways of lncRNAs are always found to be inconsistent among different types of malignancies. However, no available literature has systemically summarized differences in the functions and underlying molecular mechanisms of lncRNAs between lung cancer and other cancers. In this review, the biological functions and molecular mechanisms of lncRNAs in lung cancer were introduced. Furthermore, their functional differences between lung cancer and other malignancies were discussed. Finally, their potential clinical applications in future lung cancer therapy were focused on.

What CT characteristics of lepidic predominant pattern lung adenocarcinomas correlate with invasiveness on pathology?

OBJECTIVES

The International Association for the Study of Lung Cancer, American Thoracic Society and European Respiratory Society lung adenocarcinoma classification in 2011 defined three lepidic predominant patterns including adenocarcinoma in situ, minimally invasive adenocarcinoma and lepidic predominant adenocarcinoma. We sought to correlate the radiology and pathology findings and identify any computed tomography (CT) features which can be associated with invasive growth.

MATERIALS AND METHODS

An institutional review board approved, retrospective study was conducted evaluating 63 patients with resected, pathologically confirmed, adenocarcinomas with predominant lepidic patterns. Preoperative CT images of the nodules were assessed using quantitative and qualitative radiographic descriptors while blinded to pathologic sub-classification and size. Maximum diameter was measured after evaluation of the axial, sagittal and coronal planes. Radiologic - pathologic associations were examined using Fisher's exact test, the Kruskal-Wallis test and the Spearman correlation coefficient (ρ).

RESULTS AND CONCLUSION

Increasing maximum diameter of the whole lesion (ground glass and solid component) on CT was significantly associated with invasiveness (p = .003), as was the maximum pathologic specimen diameter (p = .008). Larger diameter of the solid component on CT was also found in lepidic predominant adenocarcinoma compared to minimally invasive adenocarcinoma (median 10.5 vs 2 mm, p = .005). More invasive tumors had higher visual estimated percentage solid component compared to whole lesion measurement on CT (p = .014). CT and pathologic measurements were positively correlated, although only moderately (ρ = .66) for the maximum whole lesion size and fair (ρ = .49) for solid/invasive component maximum measurements. Larger whole lesion size and solid component size of lepidic predominant pattern adenocarcinomas are associated with lesion invasiveness, although radiologic and pathologic lesion measurements are only fair-moderately positively correlated.

The maximum standardized uptake value of preoperative positron emission tomography/computed tomography in lung adenocarcinoma with a ground-glass opacity component of less than 30 mm

BACKGROUND AND OBJECTIVES

This study evaluated the relationship between the maximum standardized uptake value (SUVmax) of preoperative positron emission tomography/computed tomography (PET/CT) and the characteristics of lung adenocarcinoma featuring ground-glass opacity nodules (GGN).

METHODS

The association of the SUVmax of preoperative PET/CT with ground-glass opacity (GGO) proportion on CT, subtypes of adenocarcinoma (minimally invasive adenocarcinoma, invasive adenocarcinoma), predominant types of invasive adenocarcinoma, and size of the total and invasive components of pathology were evaluated in 190 patients who underwent resection for lung adenocarcinoma featuring GGN.

RESULTS

The mean SUVmax of non-solid GGN and partly solid GGN were 0.53 and 1.32, respectively (P = 0.029). The mean SUVmax of the main masses in 38 patients with MIA and 152 with invasive adenocarcinoma were 0.86 and 1.36, respectively (P = 0.029). The mean SUVmax of acinar, lepidic, papillary, and solid tumors were 1.61, 0.87, 0.98, and 1.60, respectively. The mean SUVmax of invasive components measuring ≤10 mm, 11-20 mm, and >20 mm were 0.84, 1.66, and 2.09, respectively (P < 0.001).

CONCLUSIONS

The SUVmax of lung adenocarcinoma featuring GGN can vary depending on the GGO proportion. A higher SUVmax can be expected in invasive adenocarcinoma than in MIA, and solid and acinar-predominant invasive adenocarcinoma showed a higher SUVmax.

[Surgical Treatment of Small Pulmonary Nodules Under Video-assisted Thoracoscopy (A Report of 129 Cases)]

背景与目的

影像技术的发展导致肺部微小结节尤其是肺磨玻璃结节（ground-glass opacity, GGO）检出逐年增多，但术前定性困难。本研究探讨肺部微小结节的临床诊断及微创手术治疗的必要性和可行性、病理诊断，微创切除及淋巴结切除的手术方式。

方法

对2013年12月-2016年11月接受电视胸腔镜手术（video-assisted thoracic surgery, VATS）治疗并有明确病理诊断的共129例患者的临床资料回顾性分析。所有患者术前行薄层计算机断层扫描（computed tomography, CT）扫描，其中21个微小结节术前行CT引导下Hook-wire定位，并根据病理性质及患者身体状况采用不同手术方式。

结果

共129个微小结节，实性结节（solid pulmonary nodule, SPN）37个，恶性比例是24.3%（9/37），术后病理结果为：肺原发性鳞状细胞癌3个，浸润性腺癌（invasive adenocarcioma, IA）3个，转移癌2个，小细胞肺癌（small cell lung cancer, SCLC）1个，错构瘤16个，其他炎症等良性病变12个；49个混合性GGO（mixed ground-glass opacity, mGGO）的恶性比例是63.3%（31/49），术后病理结果为：IA 19个，微浸润腺癌（micro invasive adenocarcioma, MIA）6个，原位腺癌（adenocarcioma in situ, AIS）4个，非典型性腺瘤样增生（atipical adenomatous hyperplasia, AAH）1个，SCLC 1个，炎症等良性病变18个；43个纯GGO（pure ground-glass opacity, pGGO）的恶性比例是86.0%（37/43），术后病理结果为：AIS 19个，MIA 6个，IA 6个，AAH 6个，炎症等良性病变6个；GGO总的恶性比例是73.9%（68/92）。52个良性病变均采用VATS肺楔形切除；原发性非小细胞肺癌（non-small cell lung cancer, NSCLC）共73例，VATS肺叶切除和淋巴结清扫33例，VATS肺楔形切除和选择性淋巴结切除6例，VATS肺段切除和选择性淋巴结切除6例，VATS肺楔形切除28例；2个转移癌和2个SCLC，采用VATS肺楔形切除术。另有6例患者术中冰冻病理存在误差，其中2例选择二次手术行肺叶切除和淋巴结清扫。45例有淋巴结病理结果NSCLC只有两例以SPN为表现的IA出现纵隔淋巴结转移，其余均未出现淋巴结转移。术后随访1个月-35个月，平均（15.1±10.2）个月，无复发及转移。

结论

肺部微小结节尤其是GGO，是恶性病灶的概率大，应积极外科处理；围手术期应与患者及家属充分告知冰冻病理结果存在误差可能性，避免医疗纠纷。

Optimization and validation of cryostat temperature conditions for trans-reflectance mode FTIR microspectroscopic imaging of biological tissues

In Fourier transform infrared (FTIR) microspectrocopy, the tissue preparation method is crucial, especially how the tissue is cryo-sectioned prior to the imaging requires special consideration. Having a temperature difference between the cutting blade and the specimen holder of the cryostat greatly affects the quality of the sections. Therefore, we have developed an optimal protocol for cryo-sectioning of biological tissues by varying the temperature of both the cutting blade and the specimen holder. Using this protocol, we successfully cryo-sectioned four different difficult-to-section tissues including white adipose tissue (WAT), brown adipose tissue (BAT), lung, and liver. The optimal temperatures that required to be maintained at the cutting blade and the specimen holder for the cryo-sectioning of WAT, BAT, lung, and liver are (−25, −20 °C), (−25, −20 °C), (−17, −13 °C) and (−15, −5 °C), respectively. The optimized protocol developed in this study produced high quality cryo-sections with sample thickness of 8–10 μm, as well as high quality trans-reflectance mode FTIR microspectroscopic images for the tissue sections.

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Use of cryostat technique to make thin sections of biological samples for FTIR microspectroscopy imaging.

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Optimized cryostat temperature conditions by varying the temperatures at the cutting blade and specimen holder to obtain high quality sections of difficult-to-handle tissues.

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FTIR imaging is used to obtain chemical information from cryo-sectioned samples with no interference of the conventional paraffin-embedding agent and chemicals.

Differential diagnosis of human lung tumors using surface desorption atmospheric pressure chemical ionization imaging mass spectrometry

Differential diagnosis of human lung cancer in untreated tissue is achieved by DAPCI-MSI combined with multivariate statistical analysis.

Intraoperative fine needle aspirations - diagnosis and typing of lung cancer in small biopsies: challenges and limitations

Background

Due to therapeutic implications with regard to both efficiency and safety of chemotherapy agents it is important to differentiate between subtypes of NSCLC. Up to today we experience a continuous reservation regarding the use of fine needle aspiration cytology. The aim of the present study is to estimate the value of cytologic criteria for lung cancer typing on small biopsies independent from all possible technique failures.

Methods

Between January 1997 and December 2008 760 intraoperative FNAC- (fine needle aspiration cytology) specimens from 702 patients have been examined. Cytologic evaluation and immediate communication of results to the surgeons followed. Afterwards, intraoperative cytologic findings were compared with final histologic diagnoses of the resected specimens.

Results

Intraoperative cytologic analysis yielded a sensitivity of 94.8 %, a specificity of 98.8 %. An overall positive predictive value of 99.8 % with respect to final histologic analysis of primary lung cancer was achieved. The highest value could be reached for adenocarcinomas, followed by carcinoids and squamous cell carcinomas.

Conclusions

Lung cancer typing according to cytologic criteria is feasible and accurate as well as comparable with results of histologic analysis on small specimens. Herewith, clinicians can come up to the increasing demands on minimally invasive harvested specimens with regard to therapeutic implications.

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

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

Prognosis and status of lymph node involvement in patients with adenocarcinoma in situ and minimally invasive adenocarcinoma-a systematic literature review and pooled-data analysis

BACKGROUND

Adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) have been brought up that substitute for bronchioloalveolar carcinoma (BAC), according to the new classification of lung adenocarcinoma. There has been increasing opinions that argues for the adjustment of lymph node disposition in patients with such early stage tumors. Therefore, we sought to overview the prognosis and status of lymph node involvement in AIS/MIA patients.

METHODS

PubMed, Springer and Ovid databases were searched for relevant studies. Data was extracted and results summarized to demonstrate the disposition of lymph nodes in AIS/MIA.

RESULTS

Twenty-three studies consisting of 6,137 lung adenocarcinoma were included. AIS/MIA accounted for 821 of the total 6,137. All included patients received curative surgery. After a review of the summarized data we found that only one patient (with MIA) had N1 node metastasis, N2 disease was not found in any of the included patients. In concordance with this, studies that reported 5-year disease free survival (5-year DFS) have almost 100% rate.

CONCLUSIONS

Our findings indicated that patients with AIS/MIA have good survival prognosis after surgical resection, and that recurrence and lymph node metastasis in these patients is rare. Therefore, we strongly encouraged further studies to determine the role of different lymph node disposition strategies.

Accuracy of the IASLC/ATS/ERS histological subtyping of stage I lung adenocarcinoma on intraoperative frozen sections

Histological subtyping of surgically resected lung adenocarcinoma has been shown to be of prognostic significance, and limited surgical resection has been proposed as a treatment of choice for early-stage lung adenocarcinoma. The accuracy of histological subtyping has been recently assessed in the surgical resection and small biopsy specimens; however, the accuracy of intraoperative subtyping on frozen sections remains relatively unknown. The aim of this study was to determine diagnostic accuracy and interobserver variability in histological subtyping of lung adenocarcinoma on intraoperative frozen sections. Overall, 112 consecutive cases of surgically resected stage I lung adenocarcinoma were reviewed independently by three pathologists. Histological patterns (acinar, lepidic, papillary, micropapillary, and solid) and mucinous variant were recorded in 5% increments for each intraoperative frozen and permanent sections. Primary and secondary histological patterns were assigned in each case. Kappa scores were calculated to evaluate agreement between pathologists in the assessment of histological subtype on intraoperative frozen sections versus permanent sections. Overall agreement between intraoperative frozen and permanent sections was moderate for primary pattern (69.7% of cases), with kappa scores ranging from 0.43 to 0.58, with more consistent agreement for stage IA tumors. Kappa scores for the secondary pattern ranged from 0.16 to 0.32. Acinar and solid patterns were most likely to be correctly identified as primary growth patterns. Micropapillary pattern was recognized in only 11-55% of cases. The main reasons for discrepancies between intraoperative frozen and permanent sections were inadequate sampling and poor quality of frozen sections. Our study suggests that it is difficult to predict the primary adenocarcinoma pattern on a single representative frozen section. This observation suggests a potential impact on the extent of frozen section sampling by pathologists at the time of intraoperative consultation, if surgical management of stage I lung adenocarcinoma will be guided by its histological subtype.

Tissue spray ionization mass spectrometry for rapid recognition of human lung squamous cell carcinoma

Tissue spray ionization mass spectrometry (TSI-MS) directly on small tissue samples has been shown to provide highly specific molecular information. In this study, we apply this method to the analysis of 38 pairs of human lung squamous cell carcinoma tissue (cancer) and adjacent normal lung tissue (normal). The main components of pulmonary surfactants, dipalmitoyl phosphatidylcholine (DPPC, m/z 757.47), phosphatidylcholine (POPC, m/z 782.52), oleoyl phosphatidylcholine (DOPC, m/z 808.49), and arachidonic acid stearoyl phosphatidylcholine (SAPC, m/z 832.43), were identified using high-resolution tandem mass spectrometry. Monte Carlo sampling partial least squares linear discriminant analysis (PLS-LDA) was used to distinguish full-mass-range mass spectra of cancer samples from the mass spectra of normal tissues. With 5 principal components and 30-40 Monte Carlo samplings, the accuracy of cancer identification in matched tissue samples reached 94.42%. Classification of a tissue sample required less than 1 min, which is much faster than the analysis of frozen sections. The rapid, in situ diagnosis with minimal sample consumption provided by TSI-MS is advantageous for surgeons. TSI-MS allows them to make more informed decisions during surgery.

Using frozen section to identify histological patterns in stage I lung adenocarcinoma of ≤ 3 cm: accuracy and interobserver agreement

AIMS

The IASLC/ATS/ERS classification of lung adenocarcinoma provides a prognostically significant histological subclassification. The aim of this study was to investigate the accuracy, limitations and interobserver agreement of frozen sections for predicting histological subtype.

METHODS AND RESULTS

Frozen section and permanent section slides from 361 resected stage I lung adenocarcinomas ≤ 3 cm in size were reviewed for predominant histological subtype and the presence or absence of lepidic, acinar, papillary, micropapillary and solid patterns. Fifty cases were additionally reviewed by three pathologists to determine interobserver agreement. To test the accuracy of frozen section in judging degree of invasion, five pathologists reviewed frozen section slides from 35 cases with a predominantly lepidic pattern. There was moderate agreement on predominant histological subtype between frozen sections and final diagnosis (κ = 0.565). Frozen sections had high specificity for micropapillary and solid patterns (94% and 96%, respectively), but sensitivity was low (37% and 69%, respectively). The interobserver agreement was satisfactory (κ > 0.6, except for the acinar pattern).

CONCLUSIONS

Frozen section can provide information on the presence of aggressive histological patterns-micropapillary and solid-with high specificity but low sensitivity. It was difficult to predict the predominant pattern on the basis of frozen sections, mostly because of sampling issues.

Quantitative CT analysis of pulmonary ground-glass opacity nodules for the distinction of invasive adenocarcinoma from pre-invasive or minimally invasive adenocarcinoma

Objectives

We aimed to analyze the CT findings of ground-glass opacity nodules diagnosed pathologically as adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma in order to investigate whether quantitative CT parameters enable distinction of invasive adenocarcinoma from pre-invasive or minimally invasive adenocarcinoma.

Methods

We reviewed CT images and pathologic specimens from 191 resected ground-glass opacity nodules with little or no solid component at CT. Nodule size, volume, density, mass, skewness/kurtosis, and CT attenuation values at the 2.5^th–97.5^th percentiles on histogram, and texture parameters (uniformity and entropy) were assessed from CT datasets.

Results

Of 191 tumors, 38 were AISs (20%), 61 were MIAs (32%), and 92 (48%) were invasive adenocarcinomas. Multivariate logistic regression analysis helped identify the 75^th percentile CT attenuation value (P = 0.04) and entropy (P<0.01) as independent predictors for invasive adenocarcinoma, with an area under the receiver operating characteristic curve of 0.780.

Conclusion

Quantitative analysis of preoperative CT imaging metrics can help distinguish invasive adenocarcinoma from pre-invasive or minimally invasive adenocarcinoma.

In compressed lung tissue microscopic sections of adenocarcinoma in situ may mimic papillary adenocarcinoma

CONTEXT

Surgical removal and pathologic handling of lung tissue has a compressive effect upon its architecture. The effect of surgical atelectasis on morphology has not been examined in depth, especially with respect to lung adenocarcinomas.

OBJECTIVE

To examine the influence of surgical atelectasis on morphologic lepidic growth pattern, mimicking papillary adenocarcinoma pattern.

DESIGN

In 2 cases serial sections of resected pulmonary adenocarcinoma were used, as was a 3-dimensional reconstruction. Elastin stains were performed on primary and metastatic adenocarcinomas.

RESULTS

Perfusion fixation of another case showed marked morphologic differences of less compressed peripheral lung tissue, emphasizing the preexisting alveolar structure. An elastic stain may help identify true lesional architecture.

CONCLUSIONS

We demonstrate that microscopic sections of adenocarcinoma in situ in compressed/collapsed tissue may give rise to a pseudopapillary pattern mimicking invasive adenocarcinoma. Accurate appreciation of different tumor architecture in lung adenocarcinoma has important biologic and clinical implications. Pathologists should be aware of the possibility of misclassification of adenocarcinoma pattern due to tissue artifacts caused by lung tissue handling.

Clinical relevance of the new IASLC/ERS/ATS adenocarcinoma classification

In 2011, recommendations for a multidisciplinary classification of lung adenocarcinoma were published under the auspices of the International Association for the Study of Lung Cancer, the American Thoracic Society and the European Respiratory Society. The review was considered necessary due to emerging data on the radiological features, genetics and therapeutic approaches to lung adenocarcinoma, all underpinned by expanding the knowledge of the pathology of this common tumour. The existing WHO classification of 2004 was not really fit for this multidisciplinary focus on the disease. This review describes the recommendations made on the reporting of surgically resected lung cancers according to their predominant pattern, and argues the case for replacing the term bronchioloalveolar carcinoma (WHO 1999 and 2004 definition) with adenocarcinoma in situ and for the introduction of minimally invasive adenocarcinoma. There is also a discussion of diagnosis of non-small-cell lung carcinomas in the small biopsy or cytology setting, a practice that was inadequately addressed in WHO 2004, yet this is much more relevant to most pathologists' daily practice because 85% or so of adenocarcinomas are never resected. Predictive immunohistochemistry, used correctly, can reduce non-specific diagnosis to less than 10% of the cases. Finally, there is an overview of the emerging data on therapeutically relevant lung adenocarcinoma genetics, considering targetable mutations that are now the focus of much activity. The clinical relevance of these changes is discussed.

Root cause analysis of problems in the frozen section diagnosis of in situ, minimally invasive, and invasive adenocarcinoma of the lung

CONTEXT

Frozen sections can help determine the extent of surgery by distinguishing in situ, minimally invasive, and invasive adenocarcinoma of the lung.

OBJECTIVE

To evaluate our experience with the frozen section diagnosis of these lesions using root-cause analysis.

DESIGN

Frozen sections from 224 consecutive primary pulmonary adenocarcinomas (in situ, 27 [12.1%]; minimally invasive, 46 [20.5%]; invasive, 151 [67.4%]) were reviewed. Features that could have contributed to frozen section errors and deferrals were evaluated.

RESULTS

There were no false-positive diagnoses of malignancy. Frozen section errors and deferrals were identified in 12.1% (27 of 224) and 6.3% (14 of 224) of the cases, respectively. Significantly more errors occurred in the diagnosis of in situ and minimally invasive adenocarcinoma than in the diagnosis of invasive adenocarcinoma (P < .001). Frozen section errors and deferrals were twice as frequent in lesions smaller than 1.0 cm (P = .09). Features significantly associated with errors and deferrals included intraoperative consultation by more than one pathologist (P = .003) and more than one sample of frozen lung section (P = .001). Inflammation with reactive atypia, fibrosis/scar, sampling problems, and suboptimal quality sections were identified in 51.2% (21 of 41), 36.6% (15 of 41), 26.8% (11 of 41), and 9.8% (4 of 41) of the errors and deferrals, respectively (more than one of these factors was identified in some cases). Frozen section errors and deferrals had significant clinical impact in only 4 patients (1.8%); each had to undergo completion video-assisted thoracoscopic lobectomy less than 90 days after the initial surgery.

CONCLUSIONS

The distinction of in situ from minimally invasive adenocarcinoma is difficult in both frozen and permanent sections. We identified several technical and interpretive features that likely contributed to frozen section errors and deferrals and suggest practice modifications that are likely to improve diagnostic accuracy.

[Extemporaneous examination in lung pathology: the pathologist's view]

Extemporaneous examination of a thoracopulmonary lesion has an unquestionable interest when pre-surgical diagnostic workup has not allowed determining its exact nature. This examination, the sole objective of which is to guide the surgical approach, is especially important in lung pathology, due to the limited non-surgical access to thoracic lesions and the morbidity and mortality of repeated surgery. Its yield as a decision-making procedure is of utmost importance in many clinical situations, and a close collaboration between thoracic surgeons and pathologists is required to ensure its quality, in a context of mutual confidence that requires time and experience. After a presentation of the indications and practical modalities of extemporaneous examination, we will underline its limitations and insist on difficult situations for the pathologist and inadequate indications.

Identification of biological tissues by rapid evaporative ionization mass spectrometry

The newly developed rapid evaporative ionization mass spectrometry (REIMS) provides the possibility of in vivo, in situ mass spectrometric tissue analysis. The experimental setup for REIMS is characterized in detail for the first time, and the description and testing of an equipment capable of in vivo analysis is presented. The spectra obtained by various standard surgical equipments were compared and found highly specific to the histological type of the tissues. The tissue analysis is based on their different phospholipid distribution; the identification algorithm uses a combination of principal component analysis (PCA) and linear discriminant analysis (LDA). The characterized method was proven to be sensitive for any perturbation such as age or diet in rats, but it was still perfectly suitable for tissue identification. Tissue identification accuracy higher than 97% was achieved with the PCA/LDA algorithm using a spectral database collected from various tissue species. In vivo, ex vivo, and post mortem REIMS studies were performed, and the method was found to be applicable for histological tissue analysis during surgical interventions, endoscopy, or after surgery in pathology.

CD24, a novel cancer biomarker, predicting disease-free survival of non-small cell lung carcinomas: a retrospective study of prognostic factor analysis from the viewpoint of forthcoming (seventh) new TNM classification

INTRODUCTION

Metastasis-associated protein CD24 has been identified as a new prognostic factor and stem cell marker in the human neoplasm. However, the importance of the CD24 in non-small cell lung carcinomas (NSCLCs) has not been elucidated well.

METHODS

We evaluated CD24 expression in 267 consecutive cases of NSCLC by immunohistochemistry using a tissue microarray technique and correlated with clinicopathologic parameters including forthcoming (seventh) new tumor node metastasis classification.

RESULTS

CD24-high expression was demonstrated in 87 of 267 (33%) and was associated with adenocarcinoma (ADC) histology than in squamous cell carcinoma histology (64 of 165 [39%] vs. 20 of 88 [23%]; p = 0.023). Patients with CD24-high tumors tended to have a higher risk of disease progression (p < 0.001) and cancer-related death (p = 0.002). Multivariate analysis proved CD24-high expression as independent prognostic factors of disease progression and cancer-related death (p = 0.002, hazard ratio = 1.78, 95% confidence interval = 1.23-2.58 and p = 0.017, hazard ratio = 1.93, 95% confidence interval =1.13-3.31). CD24-high expression had a tendency to correlate with new pathologic stage (p-stage) (p = 0.089) rather than old p-stage (p = 0.253). Performance status and new p-stage, regardless of the tumor histology, were identified as consistent independent prognostic factors of disease progression and cancer-related death. However, age was related to a significantly shorter cancer-specific survival in ADC only.

CONCLUSIONS

CD24 expression in NSCLC is associated with ADC histology and disease progression and cancer-related death, indicative of aggressive tumor behavior. Performance status and new p-stage, to a lesser extent, age correlated with progression-free survival and cancer-specific survival, regardless of tumor histology.

Bronchioloalveolar Carcinoma and Minimally Invasive Adenocarcinoma

The most recent WHO classification of lung cancer defines bronchioloalveolar carcinoma (BAC) as a noninvasive carcinoma or adenocarcinoma in situ. However, the use of this terminology is not uniform and does not reflect standardized criteria. As a result, the diagnosis of BAC has been used in association with small, solitary, and well-differentiated adenocarcinoma as well as tumors with advanced clinical stage. At present, there is a growing consensus among specialists in thoracic oncology that BAC or adenocarcinoma in situ is a rare tumor, and the term should be restricted to adenocarcinomas that show a pure lepidic pattern of growth. The amount of invasive component present in a tumor with a predominant lepidic growth pattern has also been under intense scrutiny. The concept of minimally invasive adenocarcinoma is developing in order to differentiate a pure BAC from an invasive adenocarcinoma that still carries an excellent prognosis.