Interpathologist Diagnostic Agreement for Non-Small Cell Lung Carcinomas Using Current and Recent Classifications

Inter-pathologist agreement on diagnosis, classification and grading of canine glioma

Histopathological evaluation of tumours is a subjective process, but studies of inter-pathologist agreement are uncommon in veterinary medicine. The Comparative Brain Tumour Consortium (CBTC) recently published diagnostic criteria for canine gliomas. Our objective was to assess the degree of inter-pathologist agreement on intracranial canine gliomas, utilising the CBTC diagnostic criteria in a cohort of eighty-five samples from dogs with an archival diagnosis of intracranial glioma. Five pathologists independently reviewed H&E and immunohistochemistry sections and provided a diagnosis and grade. Percentage agreement and kappa statistics were calculated to measure inter-pathologist agreement between pairs and amongst the entire group. A consensus diagnosis of glioma subtype and grade was achieved for 71/85 (84%) cases. For these cases, percentage agreement on combined diagnosis (subtype and grade), subtype only and grade only were 66%, 80% and 82%, respectively. Kappa statistics for the same were 0.466, 0.542 and 0.516, respectively. Kappa statistics for oligodendroglioma, astrocytoma and undefined glioma were 0.585, 0.566 and 0.280 and were 0.516 for both low-grade and high-grade tumours. Kappa statistics amongst pairs of pathologists for combined diagnosis varied from 0.352 to 0.839. 8 % of archival oligodendrogliomas and 61% of archival astrocytomas were reclassified as another entity after review. Inter-pathologist agreement utilising CBTC guidelines for canine glioma was moderate overall but varied from fair to almost perfect between pairs of pathologists. Agreement was similar for oligodendrogliomas and astrocytomas but lower for undefined gliomas. These results are similar to pathologist agreement in human glioma studies and with other tumour entities in veterinary medicine.

Effects of intra-operative fluid management under the guidance of stroke volume variability on short-term prognosis after thoracoscopic lobectomy

AIM

We aimed to explore the influence of intra-operative fluid management under the guidance of stroke volume variability (SVV) on the short-term prognosis after thoracoscopic lobectomy.

METHODS

A total of 171 eligible patients from April 2017 to April 2019 were selected. All patients received intra-operative fluid management under the guidance of SVV, and were divided into low-, middle- and high-level groups (n = 57) using a random-numbers table. The general data, respiratory function indices at different time points, haemodynamic indices at different time points, use of vasoactive drugs, short-term prognosis indices and incidence of complications were compared.

RESULTS

There were no significant differences in age, gender, operation time, one-lung ventilation time, amount of bleeding, arterial partial pressure of oxygen, arterial partial pressure of carbon dioxide, lung compliance and peak airway pressure at different time points, usage amount of anisodamine and incidence rate of complications among the three groups. In the low-level group, the fluid infusion amount and urine volume were significantly larger, the forced expiratory volume in one second (FEV1), percentage of FEV1 in the predicted value (FEV1%pred) and FEV1/forced vital capacity (FEV1/FVC) seven days after operation were higher, and the six-minute walk test (6MWT) distance was longer than those in the other two groups. The usage amount of dopamine, norepinephrine and esmolol was smaller, and the postoperative exhaust time was shorter than those in the other two groups. The low-level group had a smaller usage amount of isosorbide dinitrate injection and shorter length of postoperative hospital stay than the high-level group. Stroke volume had a significant difference at T2 and T3 in the low-level group, central venous pressure (CVP) and stroke volume had significant differences at T2 and T3 in the middle-level group, and heart rate (HR), mean arterial pressure and CVP were significantly different at T2 and T3 in the high-level group.

CONCLUSIONS

Fluid management under the guidance of low-level SVV (8% ≤ SVV ≤ 9%) was conducive to the maintenance of stable haemodynamics in patients during thoracoscopic lobectomy, thereby improving short-term prognosis.

Real-World Diagnostic Accuracy and Use of Immunohistochemical Markers in Lung Cancer Diagnostics

OBJECTIVES

Accurate and reliable diagnostics are crucial as histopathological type influences selection of treatment in lung cancer. The aim of this study was to evaluate real-world accuracy and use of immunohistochemical (IHC) staining in lung cancer diagnostics.

MATERIALS AND METHODS

The diagnosis and used IHC stains for small specimens with lung cancer on follow-up resection were retrospectively investigated for a 15-month period at two major sites in Sweden. Additionally, 10 pathologists individually suggested diagnostic IHC staining for 15 scanned bronchial and lung biopsies and cytological specimens.

RESULTS

In 16 (4.7%) of 338 lung cancer cases, a discordant diagnosis of potential clinical relevance was seen between a small specimen and the follow-up resection. In half of the cases, there was a different small specimen from the same investigational work-up with a concordant diagnosis. Diagnostic inaccuracy was often related to a squamous marker not included in the IHC panel (also seen for the scanned cases), the case being a neuroendocrine tumor, thyroid transcription factor-1 (TTF-1) expression in squamous cell carcinomas (with clone SPT24), or poor differentiation. IHC was used in about 95% of cases, with a higher number of stains in biopsies and in squamous cell carcinomas and especially neuroendocrine tumors. Pre-surgical transthoracic samples were more often diagnostic than bronchoscopic ones (72-85% vs. 9-53% for prevalent types).

CONCLUSIONS

Although a high overall diagnostic accuracy of small specimens was seen, small changes in routine practice (such as consequent inclusion of p40 and TTF-1 clone 8G7G3/1 in the IHC panel for non-small cell cancer with unclear morphology) may lead to improvement, while reducing the number of IHC stains would be preferable from a time and cost perspective.

Proceedings of the 2021 National Toxicology Program Satellite Symposium

The 2021 annual National Toxicology Program (NTP) Satellite Symposium, entitled "Pathology Potpourri," was the 20th anniversary of the symposia and held virtually on June 25th, in advance of the Society of Toxicologic Pathology's 40th annual meeting. The goal of this symposium was to present and discuss challenging diagnostic pathology and/or nomenclature issues. This article presents summaries of the speakers' talks along with select images that were presented to the audience for voting and discussion. Various lesions and topics covered during the symposium included differentiation of canine oligodendroglioma, astrocytoma, and undefined glioma with presentation of the National Cancer Institute's updated diagnostic terminology for canine glioma; differentiation of polycystic kidney, dilated tubules and cystic tubules with a discussion of human polycystic kidney disease; a review of various rodent nervous system background lesions in control animals from NTP studies with a focus on incidence rates and potential rat strain differences; vehicle/excipient-related renal lesions in cynomolgus monkeys with a discussion on the various cyclodextrins and their bioavailability, toxicity, and tumorigenicity; examples of rodent endometrial tumors including intestinal differentiation in an endometrial adenocarcinoma that has not previously been reported in rats; a review of various rodent adrenal cortex lesions including those that represented diagnostic challenges with multiple processes such as vacuolation, degeneration, necrosis, hyperplasia, and hypertrophy; and finally, a discussion of diagnostic criteria for uterine adenomyosis, atypical hyperplasia, and adenocarcinoma in the rat.

Difficulties in diagnostics of lung tumours in biopsies: an interpathologist concordance study evaluating the international diagnostic guidelines

AIMS

Accurate and reliable diagnosis is essential for lung cancer treatment. The study aim was to investigate interpathologist diagnostic concordance for pulmonary tumours according to WHO diagnostic criteria.

METHODS

Fifty-two unselected lung and bronchial biopsies were diagnosed by a thoracic pathologist based on a broad spectrum of immunohistochemical (IHC) stainings, molecular data and clinical/radiological information. Slides stained with H&E, thyroid transcription factor-1 (TTF-1) clone SPT24 and p40 were scanned and provided digitally to 20 pathologists unaware of reference diagnoses. The pathologists independently diagnosed the cases and stated if further diagnostic markers were deemed necessary.

RESULTS

In 31 (60%) of the cases, ≥80% of the pathologists agreed with each other and with the reference diagnosis. Lower agreement was seen in non-small cell neuroendocrine tumours and in squamous cell carcinoma with diffuse TTF-1 positivity. Agreement with the reference diagnosis ranged from 26 to 45 (50%-87%) for the individual pathologists. The pathologists requested additional IHC staining in 15-44 (29%-85%) of the 52 cases. In nearly half (17 of 36) of the malignant cases, one or more pathologist advocated for a different final diagnosis than the reference without need of additional IHC markers, potentially leading to different clinical treatment.

CONCLUSIONS

Interpathologist diagnostic agreement is moderate for small unselected bronchial and lung biopsies based on a minimal panel of markers. Neuroendocrine morphology is sometimes missed and TTF-1 clone SPT24 should be interpreted with caution. Our results suggest an intensified education need for thoracic pathologists and a more generous use of diagnostic IHC markers.

A Semiquantitative Scoring System May Allow Biopsy Diagnosis of Pulmonary Large Cell Neuroendocrine Carcinoma

OBJECTIVES

The aim of this study was to devise reproducible biopsy criteria for distinguishing pulmonary large cell neuroendocrine carcinoma (LCNEC) from non-small cell lung carcinoma (NSCLC).

METHODS

Tissue microarrays of LCNEC and NSCLC were generated from resection specimens and used as biopsy surrogates. They were stained for neuroendocrine markers, Ki-67, napsin-A, and p40, and independently analyzed by standardized morphologic criteria by four pathologists. Tumors were scored based on morphology, neuroendocrine marker expression, and Ki-67 proliferative index.

RESULTS

The average total score for LCNEC was significantly higher than for NSCLC (5.65 vs 0.51, P < .0001). Utilizing a cutoff score of 4 or higher showed 100% sensitivity and 99% specificity for LCNEC diagnosis, with an excellent agreement among four pathologists (98%).

CONCLUSIONS

The proposed semiquantitative approach based on a combination of specific morphologic and immunophenotypic features may be a useful tool for biopsy diagnosis of LCNEC.

Reproducibility of visual estimation of lung adenocarcinoma subtype proportions

In 2011, a new classification of lung adenocarcinoma was published. Since then there have been multiple studies regarding observer variability in predominant subtype determination, with levels of agreement generally in the weak to moderate range. In the 2011 and subsequent WHO 2015 classification, a recommendation was also made to visually assess and record the percentage of each subtype in 5% increments. The present study was initiated to determine the reproducibility of such gestalt assessments and to compare these data to a formal morphometric assessment. Five experienced pathologists reviewed multiple single images of 25 adenocarcinomas, taken at 2× and 10×, and estimated the percentage of lepidic, acinar, papillary, micropapillary, and solid components in 5% increments. After 2 months all the pathologists again reviewed the same images presented to them in a different order. We found that there was poor reproducibility within observers at 2× power using a 5% evaluation, but that this improved using 10% or 25% cutoffs. Use of 10× magnification allowed weak to moderate reproducibility at 5% increments, and this was again improved using 10% or 25% cutoffs. Correlation with morphometric assessment was poor except for the papillary and micropapillary subtypes. Differences among pathologists were generally low except for the acinar and, to a lesser degree, lepidic subtypes, which showed a wide spread of data. When estimating tumor subtype proportions, use of a 10× objective, and utilization of 10% or preferably 25% cutoffs provides a greater degree of consistency than a 5% cutoff.

Role of 18F-FDG PET/CT in establishing new clinical and therapeutic modalities in lung cancer. A short review

Lung cancer is a fairly common malignancy. An early diagnosis and a reliable staging and re-staging with the aim to detect both local and distant relapse are of utmost importance in planning the therapeutic management. The imaging diagnostic work-up of patients with lung cancer usually includes conventional imaging (chest X-ray, contrast-enhanced CT, bone scan) and more recently ¹⁸F-FDG PET/CT. Great advances in the management of lung cancer are based on the information provided by ¹⁸F-FDG PET/CT, as it supplies both metabolic and anatomic information (better localisation). There is vast evidence in the literature demonstrating its utility in (a) characterising benign versus malignant solitary nodules, (b) staging and re-staging lung cancer, (c) guiding the type of therapy, (d) monitoring treatment response and (e) predicting outcome. In particular, given its specificity in differentiating ¹⁸F-FDG-avid relapse from post-surgical changes or post-radiation fibrosis (which do not take up ¹⁸F-FDG), PET/CT can detect recurrent disease after initial treatment and (being a whole-body technique) has demonstrated high accuracy in the detection of distant metastases or secondary tumours. In conclusion, ¹⁸F-FDG PET/CT can be considered a highly accurate and reliable method for staging and re-staging lung cancer, and is highly effective in guiding personalised therapies.

A combined gene expression tool for parallel histological prediction and gene fusion detection in non-small cell lung cancer

Accurate histological classification and identification of fusion genes represent two cornerstones of clinical diagnostics in non-small cell lung cancer (NSCLC). Here, we present a NanoString gene expression platform and a novel platform-independent, single sample predictor (SSP) of NSCLC histology for combined, simultaneous, histological classification and fusion gene detection in minimal formalin fixed paraffin embedded (FFPE) tissue. The SSP was developed in 68 NSCLC tumors of adenocarcinoma (AC), squamous cell carcinoma (SqCC) and large-cell neuroendocrine carcinoma (LCNEC) histology, based on NanoString expression of 11 (CHGA, SYP, CD56, SFTPG, NAPSA, TTF-1, TP73L, KRT6A, KRT5, KRT40, KRT16) relevant genes for IHC-based NSCLC histology classification. The SSP was combined with a gene fusion detection module (analyzing ALK, RET, ROS1, MET, NRG1, and NTRK1) into a multicomponent NanoString assay. The histological SSP was validated in six cohorts varying in size (n = 11–199), tissue origin (early or advanced disease), histological composition (including undifferentiated cancer), and gene expression platform. Fusion gene detection revealed five EML4-ALK fusions, four KIF5B-RET fusions, two CD74-NRG1 fusion and three MET exon 14 skipping events among 131 tested cases. The histological SSP was successfully trained and tested in the development cohort (mean AUC = 0.96 in iterated test sets). The SSP proved successful in predicting histology of NSCLC tumors of well-defined subgroups and difficult undifferentiated morphology irrespective of gene expression data platform. Discrepancies between gene expression prediction and histologic diagnosis included cases with mixed histologies, true large cell carcinomas, or poorly differentiated adenocarcinomas with mucin expression. In summary, we present a proof-of-concept multicomponent assay for parallel histological classification and multiplexed fusion gene detection in archival tissue, including a novel platform-independent histological SSP classifier. The assay and SSP could serve as a promising complement in the routine evaluation of diagnostic lung cancer biopsies.