Cytopathologic factors can predict invasion in small-sized peripheral lung adenocarcinoma with a bronchioloalveolar carcinoma component

Scrape cytology and radiological solid size correlation can be used in the intraoperative management of subsolid lung nodules

BACKGROUND

The term radiologic subsolid lung nodule (SLN) represents a heterogeneous group of non-neoplastic and neoplastic lesions. Intraoperative evaluation (IO) is often required to differentiate and diagnose. The current study aims to investigate the feasibility and reliability of scrape cytology (SC) and radiologic solid size correlation for the IO diagnosis of SLNs.

METHODS

Sixty-eight patients with SLN signs were eligible to take part in the study due to intraoperatively prepared SC slides. We managed to complete the blind radiologic solid size measurement and cytologic evaluation retrospectively. Cases were grouped into three categories based on their cytological features: Group-0 (Benign), Group-1 (mild atypical features), and Group-2 (severe atypical features/unequivocally carcinoma). IO diagnoses were given by combining the radiologic solid size and cytological findings.

RESULTS

Cytological features of Group-1 were observed in 100%, 93%, 32.5%, and 17% of the AIS, MIA, IA, and benign lesions, respectively. Cytological features of Group-2 were observed in 67.5%, and 7% of the IA and MIA, respectively. By combining cytology with radiologic solid size, 100%, 85%, 71%, and 83% of the AIS, IA, MIA, and benign lesions respectively were diagnosed correctly. Fifteen (15%) percent of the IA cases were underdiagnosed as MIA since their radiological solid sizes were less than 0.5 cm with cytological features of Group-1. Conversely, 29% of the MIA cases were overdiagnosed as IA since their radiological solid sizes were greater than 0.5 cm.

CONCLUSION

SLNs should be handled with caution in terms of IO management. SC and radiologic solid size correlation both provide a practical and tissue-protecting approach for the IO evaluation of SLNs, ensuring a high consistency between IO and definitive diagnosis.

Novel imprint cytological classification is correlated with tumor spread through air spaces in lung adenocarcinoma

OBJECTIVES

Spread through air spaces (STAS) is a risk factor for local recurrence after sublobar resection in lung cancer patients. We recently proposed the novel Nakayama-Higashiyama imprint cytological classification (N-H classification) based on small-sized lung adenocarcinoma surgical specimens, which correlated with histological patterns and nodal involvement. This study aimed to evaluate the correlation between STAS and the N-H classification and to validate the N-H classification as an intraoperative predictor of the presence of STAS.

MATERIALS AND METHODS

We retrospectively analyzed 164 intraoperative imprint cytologies and their paired histologic specimens from patients undergoing surgical resection for lung adenocarcinoma in our institute in 2017-2019. Using the NH classification, imprint cytological findings were classified into 5 groups (Groups I to V) based on cell cluster shape, cell and nucleus size, and the existence of necrosis. We examined the characteristics of imprint cytology and STAS in the resected tissues and analyzed the relationship between them.

RESULTS

Tumor STAS was observed in 29 (17.7 %) cases. The presence of STAS was significantly associated with the NH classification (P < 0.0001). STAS was present in 6 of 57 cases (10.5 %) in NH classification Group II, 11 of 42 cases (26.2 %) in Group III, and 12 of 28 cases (42.9 %) in Group IV/V; STAS was not observed in any case in Group I. Logistic regression analysis revealed that tumors with a ground glass opacity rate of <50 % on computed tomography (P = 0.00867) and Groups III-V of the NH classification (P = 0.00201) were significant independent predictors for STAS.

CONCLUSION

Intraoperative imprint cytology with the N-H classification for lung adenocarcinoma is well correlated with the STAS status of the tumor and might have applications as an intraoperative predictive marker of STAS. This classification may be useful for intraoperative detection of STAS and in the decision-making process for the surgical procedure.

Novel Imprint Cytological Classification for Small Pulmonary Adenocarcinoma Using Surgical Specimens: Comparison with the 8th Lung Cancer Staging System and Histopathological Classification

Objectives: Small-size lung lesions suspected of being cancer are now often being identified on computed tomography. Correspondingly, a new lung cancer staging system has been proposed by the International Association for the Study of Lung Cancer (IASLC), in which the T1 factor and adenocarcinoma are re-subclassified. Previously, we proposed an intraoperative cytological diagnosis and its classification of small-size lung adenocarcinoma, which correlated significantly with clinical malignancy, to be used for selecting the surgical strategy. In the current study, the correlation of our intraoperative cytological classification with the new 8th IASLC classification was investigated. Materials and Methods: A total of 139 consecutive small-size lung adenocarcinoma cases were surgically resected from 2000 to 2006 and included in this study. Intraoperative stump imprint cytology using these specimens was performed, and the cases were classified into 5 groups based on our classification. The cytological classification was compared with the IASLC classification and the WHO histopathological grading. Results: According to our classification, 32 patients were in Group I, 38 in Group II, 24 in Group III, 27 in Group IV, and 18 in Group V. Compared with the IASLC classification, most of Group I was pTis or pT1mi, and most of Group II was pT1mi or pT1a (p<0.001). There was also a significant relationship between lymph node metastasis and our cytological classification (p<0.001). The histological patterns according to the WHO classification also had a significant relationship with our classification (p<0.001). Conclusion: Our cytological classification correlated not only with the T classification, but also with the adenocarcinoma subclassification of the 8th IASLC classification.

Intraoperative Diagnosis and Surgical Procedure with Imprint Cytology for Small Pulmonary Adenocarcinoma

Objectives: For patients with multiple small-sized pulmonary cancers, a lobectomy can disrupt future therapeutic options for other lesions. It was recently reported that limited pulmonary resections were not inferior to lobectomy for the management of selected peripheral small-sized pulmonary adenocarcinomas. Patients with adenocarcinoma in situ or minimally invasive adenocarcinoma, as proposed by the International Association for the Study of Cancer classification, have been reported to have 100% survival after 5 years. However, that classification can be applied postoperatively. Since 2005, we have been intentionally performing limited pulmonary resection procedures for small-sized adenocarcinoma cases based on intraoperative imprint cytological diagnosis and our classification (Nakayama-Higashiyama's classification). Materials and Methods: A total of 120 consecutive cases were included in this study. Lung tumors were removed intraoperatively by wedge resection, and stump smear cytology was performed, from which the cases were classified into 5 groups based on our classification. When the tumor was classified as Group I or II, the operation was finished. When diagnosed as a more advanced classification, a lobectomy and lymph node dissection were additionally performed. Results: The 5-year survival rate for Group I and II was 100%, while those for Group III and IV-V were 95.8% and 94.4%, respectively. The 5-year disease-free survival rates for Group I and Group II were 100% and 97.1%, respectively, and for Group III and IV-V they were 100% and 94.1%, respectively. Conclusion: Use of cytological findings along with Nakayama-Higashiyama's classification for determining operation procedure is effective for treatment of patients with small-sized pulmonary adenocarcinoma.

A grading system combining architectural features and mitotic count predicts recurrence in stage I lung adenocarcinoma

The International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) has recently proposed a new lung adenocarcinoma classification. We investigated whether nuclear features can stratify prognostic subsets. Slides of 485 stage I lung adenocarcinoma patients were reviewed. We evaluated nuclear diameter, nuclear atypia, nuclear/cytoplasmic ratio, chromatin pattern, prominence of nucleoli, intranuclear inclusions, mitotic count/10 high-power fields (HPFs) or 2.4 mm(2), and atypical mitoses. Tumors were classified into histologic subtypes according to the IASLC/ATS/ERS classification and grouped by architectural grade into low (adenocarcinoma in situ, minimally invasive adenocarcinoma, or lepidic predominant), intermediate (papillary or acinar), and high (micropapillary or solid). Log-rank tests and Cox regression models evaluated the ability of clinicopathologic factors to predict recurrence-free probability. In univariate analyses, nuclear diameter (P=0.007), nuclear atypia (P=0.006), mitotic count (P<0.001), and atypical mitoses (P<0.001) were significant predictors of recurrence. The recurrence-free probability of patients with high mitotic count (≥5/10 HPF: n=175) was the lowest (5-year recurrence-free probability=73%), followed by intermediate (2-4/10 HPF: n=106, 80%), and low (0-1/10 HPF: n=204, 91%, P<0.001). Combined architectural/mitotic grading system stratified patient outcomes (P<0.001): low grade (low architectural grade with any mitotic count and intermediate architectural grade with low mitotic count: n=201, 5-year recurrence-free probability=92%), intermediate grade (intermediate architectural grade with intermediate-high mitotic counts: n=206, 78%), and high grade (high architectural grade with any mitotic count: n=78, 68%). The advantage of adding mitotic count to architectural grade is in stratifying patients with intermediate architectural grade into two prognostically distinct categories (P=0.001). After adjusting for clinicopathologic factors including sex, stage, pleural/lymphovascular invasion, and necrosis, mitotic count was not an independent predictor of recurrence (P=0.178). However, patients with the high architectural/mitotic grade remained at significantly increased risk of recurrence (high vs low: P=0.005) after adjusting for clinical factors. We proposed this combined architectural/mitotic grade for lung adenocarcinoma as a practical method that can be applied in routine practice.

A nuclear grading system is a strong predictor of survival in epitheloid diffuse malignant pleural mesothelioma

Epithelioid mesothelioma is the most prevalent subtype of diffuse malignant pleural mesothelioma in which only staging is prognostic for survival. In this study of epithelioid diffuse malignant pleural mesothelioma, we investigate the prognostic utility of nuclear features. The slides of 232 epithelioid diffuse malignant pleural mesothelioma patients (14 stage I, 54 stage II, 130 stage III, and 34 stage IV) from a single institution were reviewed for the following seven nuclear features: nuclear atypia, nuclear/cytoplasmic ratio, chromatin pattern, intranuclear inclusions, prominence of nucleoli, mitotic count, and atypical mitoses. MIB-1 immunohistochemistry was performed using tissue microarray, and MIB-1 labeling index was recorded as the percentage of positive tumor cells. Median overall survival of all patients was 16 months and correlated with nuclear atypia (P<0.001), chromatin pattern (P=0.031), prominence of nucleoli (P<0.001), mitotic count (P<0.001), and atypical mitoses (P<0.001) by univariate analysis. Multivariate analysis revealed nuclear atypia (P=0.012) and mitotic count (P<0.001) as independent prognostic factors, and these two factors were utilized to create a three-tier nuclear grade score. The resulting nuclear grade stratified patients into three distinct prognostic groups: grade I (n=107, median overall survival=28 months), grade II (n=91, 14 months), and grade III (n=34, 5 months). Not only was nuclear grade an independent predictor of overall survival (P<0.001), but it was also a stronger discriminator of survival than all currently available factors. Furthermore, nuclear grade was associated with time to recurrence (P=0.004) in patients who underwent complete surgical resection (n=159). MIB-1 labeling index correlated with mitotic count (P<0.001) and nuclear atypia (P=0.037) and stratified overall survival (P<0.001) and time to recurrence (P=0.048), confirming the prognostic value of the nuclear grade. Nuclear grading in epithelioid mesothelioma provides a simple, practical, and cost-effective prognostic tool that better stratifies clinical outcome and time to recurrence than currently available clinicopathologic factors.

Upregulation of notch2 and six1 is associated with progression of early-stage lung adenocarcinoma and a more aggressive phenotype at advanced stages

PURPOSE

Lung adenocarcinoma often manifests as tumors with mainly lepidic growth. The size of invasive foci determines a diagnosis of in situ, minimally invasive adenocarcinoma, or invasive types and suggests that some adenocarcinomas undergo malignant progression in that order. This study investigates how transcriptional aberrations in adenocarcinoma cells at the early stage define the clinical phenotypes of adenocarcinoma tumors at the advanced stage.

EXPERIMENTAL DESIGN

We comprehensively searched for differentially expressed genes between preinvasive and invasive cancer cells in one minimally invasive adenocarcinoma using laser capture microdissection and DNA microarrays. We screened expression of candidate genes in 11 minimally invasive adenocarcinomas by reverse transcriptase PCR and examined their involvement in preinvasive-to-invasive progression by transfection studies. We then immunohistochemically investigated the presence of candidate molecules in 64 samples of advanced adenocarcinoma and statistically analyzed the findings, together with clinicopathologic variables.

RESULTS

The transcription factors Notch2 and Six1 were upregulated in invasive cancer cells in all 11 minimally invasive adenocarcinomas. Exogenous Notch2 transactivated Six1 followed by Smad3, Smad4, and vimentin, and enlarged the nuclei of NCI-H441 lung epithelial cells. Immunochemical staining for the transcription factors was double positive in the invasive, but not in the lepidic growth component of a third of advanced Ads, and the disease-free survival rates were lower in such tumors.

CONCLUSIONS

Paired upregulation of Notch2 and Six1 is a transcriptional aberration that contributes to preinvasive-to-invasive adenocarcinoma progression by inducing epithelial-mesenchymal transition and nuclear atypia. This aberration persisted in a considerable subset of advanced adenocarcinoma and conferred a more malignant phenotype on the subset.

Cytological features of signet-ring cell carcinoma of the lung: comparison with the goblet-cell-type adenocarcinoma of the lung

Signet-ring cell carcinoma (SRCC) and goblet-cell-type adenocarcinoma (GCA) are mucin-producing lung adenocarcinomas. Primary SRCC shows an aggressive clinical course, whereas GCA shows infrequent distant metastasis, but more frequent intrapulmonary metastases resembling lobar pneumonia. To distinguish SRCC from GCA, this study investigated the respective cytological features of these lesions. We selected 10 cases each of SRCC and GCA from the archival imprint smears. We assessed them for the following 10 cytological features. Necrosis/debris was observed in 60% of the SRCC and 90% of the GCA. A mucinous background was observed in 10% of the SRCC and 90% of the GCA. Significant inflammation was observed in none of the SRCC and 80% of the GCA. Stromal cluster was observed in 30% of the SRCC and 70% of the GCA. Nuclear overlapping was observed in 50% of the SRCC and in all of the GCA. Single tumor cells were observed in 80% of the SRCC and 10% of the GCA. Honeycomb-like cluster was observed in none of the SRCC and 80% of the GCA. Prominent nucleolus was observed in 50% of the SRCC and 40% of the GCA. Nuclear membrane irregularity was observed in 70% of SRCC and 60% of the GCA. Nuclear pleomorphism was observed in all of the SRCC and none of the GCA. The cytological features of SRCC were the presence of single tumor cells and nuclear pleomorphism, whereas that of GCA were the presence of abundant mucin and significant inflammation in the background, and a honeycomb-like cluster.