Cost-benefit analysis of using large-format histology sections in routine diagnostic breast care

Multifocal and diffusely infiltrating breast cancers are highly fatal subgroups needing further improvement in diagnostic and therapeutic strategies

Physicians treating breast cancer patients often wonder why this dreaded disease is still fatal in some women despite our best diagnostic and therapeutic efforts. Our own studies on prospectively documented cases spanning several decades have given us new insights for approaching this problem. By using imaging biomarkers to classify breast cancer subtypes according to their apparent site of origin, we found that a majority of breast cancer deaths (71%) occur in a minority of breast cancers (45%). Breast cancer deaths are significantly more likely to occur in women with multifocal acinar adenocarcinoma of the breast, AAB (13.1%), diffusely invasive breast cancers of ductal origin, DAB (24 %) and breast malignancies of mesenchymal hybrid cell origin, BCMO (33.7%) compared with women having unifocal invasive breast cancers (6.1%). Preventing more of these fatal events will require a re-evaluation of the current imperfect histopathologic terminology of breast cancer with special attention to the diffuse breast cancer subtypes, intensification of multimodality imaging and multidisciplinary management, as well as application of image guided large format histopathology.

Can we improve breast cancer management using an image-guided histopathology workup supported by larger histopathology sections?

PURPOSE

Breast radiologists examine the entire breast in full-size images, while breast pathologists examine small tissue samples at high magnification. The diagnostic information from these complementary imaging approaches can be difficult to integrate for a more clinically relevant evaluation of malignancies spanning several centimetres. We have explored the advantages and disadvantages of imaging guided larger section pathology techniques compared with the standard 2 × 2.5 cm. small section technique.

METHODS

We compared the ability of conventional small section histopathology with larger section histopathology techniques to examine surgical resection margins and full disease extent. We evaluated the pre-surgical imaging workup and use of microfocus magnification radiography of sliced surgical specimens in the histopathologic evaluation of disease extent and status of surgical margins.

RESULTS

Image assisted large section histopathology of excised breast tissue enables comprehensive examination of an approximately tenfold larger contiguous tissue area than is provided by conventional small section technology. Attempting to cover the full area of each consecutive slice of resected tissue is more labour-intensive and expensive with the small section approach and poses challenges in reconstituting three-dimensional tumour architecture after morcellation and sectioning. Restricting histopathologic examination to a limited number of samples provides an incomplete evaluation of surgical margins.

CONCLUSIONS

A considerably improved documentation of breast cancer and a more reliable assessment of tissue margins is provided by using larger sized histopathology samples to correlate with breast imaging findings. These in turn can enable more appropriate treatment planning, improved surgical performance, fewer recurrences, and better patient outcome. Uncertainty of surgical margin evaluation inherent to the standard small section technique can lead to inappropriate decisions in surgical management and adjunctive therapy. Progress in breast diagnosis and treatment will largely depend on whether histopathology terminology and technique will undergo a revolution similar to the one that has already occurred in breast imaging.

Progress on deep learning in digital pathology of breast cancer: a narrative review

BACKGROUND AND OBJECTIVE

Pathology is the gold standard criteria for breast cancer diagnosis and has important guiding value in formulating the clinical treatment plan and predicting the prognosis. However, traditional microscopic examinations of tissue sections are time consuming and labor intensive, with unavoidable subjective variations. Deep learning (DL) can evaluate and extract the most important information from images with less need for human instruction, providing a promising approach to assist in the pathological diagnosis of breast cancer. To provide an informative and up-to-date summary on the topic of DL-based diagnostic systems for breast cancer pathology image analysis and discuss the advantages and challenges to the routine clinical application of digital pathology.

METHODS

A PubMed search with keywords ("breast neoplasm" or "breast cancer") and ("pathology" or "histopathology") and ("artificial intelligence" or "deep learning") was conducted. Relevant publications in English published from January 2000 to October 2021 were screened manually for their title, abstract, and even full text to determine their true relevance. References from the searched articles and other supplementary articles were also studied.

KEY CONTENT AND FINDINGS

DL-based computerized image analysis has obtained impressive achievements in breast cancer pathology diagnosis, classification, grading, staging, and prognostic prediction, providing powerful methods for faster, more reproducible, and more precise diagnoses. However, all artificial intelligence (AI)-assisted pathology diagnostic models are still in the experimental stage. Improving their economic efficiency and clinical adaptability are still required to be developed as the focus of further researches.

CONCLUSIONS

Having searched PubMed and other databases and summarized the application of DL-based AI models in breast cancer pathology, we conclude that DL is undoubtedly a promising tool for assisting pathologists in routines, but further studies are needed to realize the digitization and automation of clinical pathology.

Mass and non-mass breast MRI patterns: a radiologic approach to sick lobe theory

BACKGROUND

According to sick lobe theory, one or more lobes of the breast are more prone to the development of carcinoma. However, the implications of this theory in breast magnetic resonance imaging (MRI) are unknown.

PURPOSE

To evaluate the MRI appearance of mass type (multifocal and multicentric diseases) and non-mass type (non-mass enhancements) sick lobe patterns, together with the histopathology results.

MATERIAL AND METHODS

MRI reports of 2015 patients in two tertiary breast imaging centers between June 2012 and June 2018 were retrospectively reviewed for multifocal-multicentric diseases and segmental, linear, and regional enhancements. A total of 113 patients were included. The specimens obtained by thick needle, vacuum, excisional biopsy/lumpectomy or mastectomy after breast MRI scans were pathologically assessed. The pathologic results were categorized as invasive carcinoma, precursor, and benign proliferative lesions according to the 2012 World Health Organization Classification of Tumors.

RESULTS

The percentage of underlying benign and precursor invasive lesions was significantly different in patients with mass and non-mass MRI patterns. While the pathology results of mass type patterns were premalignant and malignant in all cases, nearly half of the underlying histologies were benign proliferative subtypes in patients with non-mass type patterns.

CONCLUSION

In this study, the mass and non-mass patterns derived from sick lobe theory were related to different risks of malignancy in the pathological examinations.

Application of large format tissue processing in the histology laboratory

In clinical, research and veterinary laboratories of North America, large format histology has more recently been improved with newer equipment and better methodology. Large tissue specimens are frequently sliced in the grossing room and processed in multiple smaller, standard size tissue cassettes. Justifiably, submitting more blocks inherently lends itself to a greater confidence in the accuracy of the diagnosis, yet guidelines for tissue sampling often suggest taking fewer samples. For example, large tumor specimen protocols recommend taking one standard-sized tissue block for each cm diameter of tumor. However, cancers are the culmination of many complex changes in cell metabolism and often appear dissimilar at different tissue locations. As these changes have an uncertain behavior, many other tissue samples are often taken from areas that appear to have either a variable texture or color. Consequently, at microscopy, the complete tissue sample may need to be reassembled like a jigsaw puzzle as the stained sections are frequently presented over many slides. This problem has easily been overcome by using large format cassettes since the entire cross-section of the tissue sample can often be viewed on a single slide. Because these cassettes can effectively hold up to 10 times the volume of conventional standard size cassettes, they are a more efficient way of assessing large areas of tissue samples. This system is easily adapted for all tissue types and has become the established method for assessing large tissue samples in many laboratory settings.

A Survey on Coronary Atherosclerotic Plaque Tissue Characterization in Intravascular Optical Coherence Tomography

PURPOSE OF REVIEW

Atherosclerotic plaque deposition within the coronary vessel wall leads to arterial stenosis and severe catastrophic events over time. Identification of these atherosclerotic plaque components is essential to pre-estimate the risk of cardiovascular disease (CVD) and stratify them as a high or low risk. The characterization and quantification of coronary plaque components are not only vital but also a challenging task which can be possible using high-resolution imaging techniques.

RECENT FINDING

Atherosclerotic plaque components such as thin cap fibroatheroma (TCFA), fibrous cap, macrophage infiltration, large necrotic core, and thrombus are the microstructural plaque components that can be detected with only high-resolution imaging modalities such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT). Light-based OCT provides better visualization of plaque tissue layers of coronary vessel walls as compared to IVUS. Three dominant paradigms have been identified to characterize atherosclerotic plaque components based on optical attenuation coefficients, machine learning algorithms, and deep learning techniques. This review (condensation of 126 papers after downloading 150 articles) presents a detailed comparison among various methodologies utilized for plaque tissue characterization, classification, and arterial measurements in OCT. Furthermore, this review presents the different ways to predict and stratify the risk associated with the CVD based on plaque characterization and measurements in OCT. Moreover, this review discovers three different paradigms for plaque characterization and their pros and cons. Among all of the techniques, a combination of machine learning and deep learning techniques is a best possible solution that provides improved OCT-based risk stratification.

The Perfect Pathology Report After Neoadjuvant Therapy

Neoadjuvant therapy is increasingly being used in the management of breast cancer patients and, since comprehensive specimen handling and precise histological reporting is essential to assess the degree of response to therapy, histopathologists are acknowledged to play a key role in this multidisciplinary setting. However, as a matter of fact, only minimal guidelines for specimen handling are on record. This means that in every day routine practice it is not uncommon for oncologists to deal with pathology reports where important parameters are missing (such as formal comments about therapy response). According to the latest American Joint Committee on Cancer (AJCC) staging classification, posttreatment size of residual disease (ypT) should be estimated based on the best combination of imaging, gross and microscopic histological findings. Therefore, pathologists should ideally be provided with clinical and radiological information before proceeding with careful grossing. During the cut-up, large sections or extensive mapping of samples submitted to microscopic evaluation should be carried out to reconstruct the disease extent: this is particularly crucial when the lesion is unapparent both at imaging and at macroscopic observation. Histopathological reports cannot preclude from mandatory information about the presence of residual invasive carcinoma, such as histotyping, staging (ypTNM), reevaluation of prognostic and predictive factors, and categorization of degree of response according to dedicated classification systems (performed by comparing pretreatment biopsies with surgical specimens). In this review we will analyze the critical issues in such an assessment and we will provide a pragmatic approach with the intent to aim at the "perfect" pathology report.

Whole-mount evaluation of penectomies for penile cancer: feasibility, cost and comparison to routine sectioning

AIMS

Pathological staging in penectomies may be difficult due to the anatomical complexity of penile anatomy, and may be additionally challenging due to the low volume at most institutions. Our study aimed to assess the feasibility of whole-mount processing for penectomy specimens.

METHODS AND RESULTS

A 7-year retrospective search for partial or radical penectomies identified 55 specimens, which were processed routinely (n = 31) from 2006 to 2009 and whole-mounted (n = 24) from 2010 to 2012. Routine cases used more slides per case compared to whole mounts (mean 10.4 versus 7.2). Recuts occurred more often in routine cases (12.9% versus 0%). More routine cases had additional blocks grossed (19.4% versus 4.2%). Upon review, five discrepancies that impacted pT staging were identified in the routine group, with none in the whole-mount group. The average estimated additional cost for each whole-mount case compared to routine processing was $40.74, with an increased turnaround time of 1 day.

CONCLUSIONS

Whole-mounting is a feasible technique for penectomy that can be utilized with minimal increased cost and turnaround time, and may improve staging. Institutions in which whole-mounting is already established for other organs, such as prostate, may wish to consider utilizing this format for penectomy specimens.

The value of large sections in surgical pathology

Large format sections (LS) first have been introduced in breast pathology more than a century ago. Since then, they constituted for longtime a research tool to better understand breast microanatomy and the relationship between radiological images and pathological features. Similarly LS have been used to study neoplastic, inflammatory, and degenerative diseases affecting various organs, as brain, lung, gastrointentinal tract, bone, urinary tract, prostate, and placenta. Currently LS are mostly applied to diagnostic routine to better stage tumours such as prostate and breast carcinomas or to correlate radiologic imaging to gross specimens. The purpose of the present paper is to review the historical background and the basis of the applications of LS in surgical pathology, with special emphasis on breast tumours.

The role of large-format histopathology in assessing subgross morphological prognostic parameters: a single institution report of 1000 consecutive breast cancer cases

Breast cancer subgross morphological parameters (disease extent, lesion distribution, and tumor size) provide significant prognostic information and guide therapeutic decisions. Modern multimodality radiological imaging can determine these parameters with increasing accuracy in most patients. Large-format histopathology preserves the spatial relationship of the tumor components and their relationship to the resection margins and has clear advantages over traditional routine pathology techniques. We report a series of 1000 consecutive breast cancer cases worked up with large-format histology with detailed radiological-pathological correlation. We confirmed that breast carcinomas often exhibit complex subgross morphology in both early and advanced stages. Half of the cases were extensive tumors and occupied a tissue space ≥40 mm in its largest dimension. Because both in situ and invasive tumor components may exhibit unifocal, multifocal, and diffuse lesion distribution, 17 different breast cancer growth patterns can be observed. Combining in situ and invasive tumor components, most cases fall into three aggregate growth patterns: unifocal (36%), multifocal (35%), and diffuse (28%). Large-format histology categories of tumor size and disease extent were concordant with radiological measurements in approximately 80% of the cases. Noncalcified, low-grade in situ foci, and invasive tumor foci <5 mm were the most frequent causes of discrepant findings.

Large format histology may aid in the detection of unsuspected pathologic findings of potential clinical significance: a prospective multiyear single institution study

Large format histology offers several unique advantages over traditional tissue processing. Over 12 years of experience with this technique provide insight into its limitations and benefits. We conducted a prospective multiyear analysis of the potential advantages of large format histology. 656 cases were examined prospectively over an eight-year period. In 172 cases the sign-out pathologist documented an unexpected finding of potential clinical significance as present only on the large format sections and not present on the accompanying standard format slides. These include closer margins, a change in size or extent of disease, and previously undocumented invasive and/or in situ carcinoma. Based on over a decade of experience and eight years of data, our results demonstrate that a quarter of cases had an unexpected finding of potential clinical significance that may not have been fully realized without the use of the large format technique.

Disease Extent ≥4 cm Is a Prognostic Marker of Local Recurrence in T1-2 Breast Cancer

Despite improvements of the therapy for breast cancer, a proportion of the patients still get local recurrence. The status of the surgical margins is the most often used parameter for decision regarding additional treatment. However, a negative margin is not a guarantee that there is not residual cancer left in the breast; additional parameters are needed to better predict the risk of local recurrence. The disease extent was evaluated in the surgical specimen from 313 women after breast-conserving therapy using large-section histology and was correlated to the incidence of local recurrence. A disease extent ≥4 cm was shown to be an independent marker for local recurrence; the cumulative 10-year local relapse rate for the group with a disease extent ≥4 cm was 20.5%, and for the rest 6.7%. We conclude that disease extent ≥4 cm seems to be an important factor when evaluating the risk for local recurrence.

Breast cancer multifocality, disease extent, and survival

The prognostic information implied in subgross morphologic parameters such as lesion distribution (unifocal, multifocal, or diffuse) and disease extent in breast cancer has remained largely unexplored in the literature. We aimed to test whether these parameters influence survival in breast carcinoma. The parameters were assessed in a series of 574 cases, all documented in large-format histology sections. We used Cox proportional hazards regression accompanied by Kaplan-Meyer survival curves, with P < .05 regarded as significant. The invasive component was unifocal in 62% (311/499), multifocal in 24% (122/499), and diffuse in 5% (26/499) of the cases. Combining the in situ and invasive tumor components resulted in 48% (274/574) unifocal, 25% (141/574) multifocal, and 20% (117/574) diffuse tumors. Sixty percent (347/574) of the tumors were categorized as having limited extent (occupying an area <40 mm in largest dimension) and 29% (164/574) as extensive. Highly significant (P < .0001) differences were observed in 10-year disease-specific cumulative survival among the cases with unifocal, multifocal, and diffuse invasive (89.6%, 76.0%, and 63.6%, respectively) and combined (92.3%, 82.3%, and 75.7%, respectively) lesion distribution. Patients with extensive tumors exhibited a significantly lower cumulative survival (P < .0001) compared with those with limited extent (91.6% and 75.5%) and a statistically significantly 1.89-fold (95% confidence interval, 1.07-3.37; P = .03) risk for breast cancer death after controlling for tumor attributes, type of surgery, and adjuvant therapy. The hazard ratio for breast cancer death for mutifocal and/or diffuse tumors versus unifocal ones was 1.96 (95%; 1.11-3.48; P = .02) after controlling for the same factors. Lesion distribution and disease extent represent important independent survival-related prognostic parameters in breast carcinoma.

The role of radiological-pathological correlation in diagnosing early breast cancer: the pathologist's perspective

Early breast carcinoma, defined as purely in situ cancer and invasive carcinomas < 15 mm, represents the most frequent category of breast carcinomas in diagnostic routine in a regularly screened population. These tumors are usually detected with mammography screening and are preoperatively characterized with radiological imaging. The role of pathology in preoperative settings is to help understand the subgross morphology and to confirm malignancy in biopsy material. Postoperatively, the pathologist needs to verify the size of the cancer (defined as the largest dimension of the largest invasive focus), the extent of the disease (defined as the area or the volume of the breast tissue containing all the malignant foci), the distribution of the in situ and invasive lesions (as unifocal, multifocal, or diffuse), and intratumoral and intertumoral heterogeneity (in addition to determining margin status, histologic tumor type, hormone receptor status, and other parameters). Despite their small size, early breast carcinomas often exhibit complex morphology as they are multifocal/diffuse in about 60% and extensive (occupying an area ≥ 4 cm) in 40% of the cases. Routine use of large-format histopathology technique is a prerequisite for detailed correlation of the radiologic and histopathologic findings and for the correct assessment of these parameters. Breast pathologists must be aware of the advantages and disadvantages of the different imaging modalities and have detailed information about the radiological findings before work-up of the operative specimen. Multidisciplinary preoperative and postoperative tumor board meetings are essential in guiding the pathologists and in confirming the radiological findings. Interdisciplinary diagnosis is inevitably becoming the new gold standard in the diagnosis and management of early breast carcinomas.