Precursor Lesions of the Low-Grade Breast Neoplasia Pathway

Unraveling the role of stromal disruption in aggressive breast cancer etiology and outcomes

BACKGROUND

Aggressive (typically high-grade) breast cancers (BCs) remain major contributors to BC-related mortality globally. The tissue changes underpinning their etiology and outcomes, however, remain poorly characterized.

METHODS

Spatially resolved machine-learning algorithms were used to characterize "stromal disruption" as a morphological metric of reduced/altered extracellular matrix and increased immune, inflammatory, and/or wound response-related processes in normal, benign breast disease (BBD), and invasive hematoxylin and eosin (H&E)-stained breast tissues. Associations of stromal disruption with BC etiologic factors were assessed among 4023 healthy breast tissue donors, its impact on BC incidence was assessed among 974 BBD patients in a nested case-control study, while its prognostic associations were assessed in 4 BC patient cohorts (n = 4223).

RESULTS

Epidemiologic risk factors for aggressive BC, including younger age, multiparity, Black race, obesity, and family history, demonstrated strong associations with increasing stromal disruption in H&E sections prior to tumor development. Substantial stromal disruption in BBD H&E was associated with ∼4-fold increased risk of aggressive (high-grade) BC and ∼3 years shorter latency from BBD to BC diagnosis, independently of BBD histology. Across BC cohorts, stromal disruption in H&E was associated with aggressive (mostly high-grade) tumor phenotypes and with markedly poor prognosis among ER-positive patients, irrespective of histology. The immunobiology of stromal disruption reflected heightened innate (CD68+), adaptive (CD3+CD4+, CD3+CD8+), immunoregulatory (CD3+CD4+FOXP3+), immune escape (PD1+PDL1+), endothelial (CD31+), and myofibroblast (α-SMA+) marker expression.

CONCLUSION

Our findings highlight the active stromal role in aggressive BC etiology and outcomes, opening possibilities for readily identifying high-risk women across the BC continuum that may benefit from stroma-centric preventative or therapeutic strategies.

Spatially Resolved Single-Cell Morphometry of Benign Breast Disease Biopsy Images Uncovers Quantitative Cytomorphometric Features Predictive of Subsequent Invasive Breast Cancer Risk

Currently, benign breast disease (BBD) pathologic classification and invasive breast cancer (BC) risk assessment are based on qualitative epithelial changes, with limited utility for BC risk stratification for women with lower-risk category BBD (ie, nonproliferative disease [NPD] and proliferative disease without atypia [PDWA]). Here, machine learning-based single-cell morphometry was used to characterize quantitative changes in epithelial nuclear morphology that reflect functional/structural decline (ie, increasing nuclear size, assessed as epithelial nuclear area and nuclear perimeter), altered DNA chromatin content (ie, increasing nuclear chromasia), and increased cellular crowding/proliferation (ie, increasing nuclear contour irregularity). Cytomorphologic changes reflecting chronic stromal inflammation were assessed using stromal cellular density. Data and pathology materials were obtained from a case-control study (n = 972) nested within a cohort of 15,395 women diagnosed with BBD at Kaiser Permanente Northwest (1971-2012). Odds ratios (ORs) and 95% confidence intervals (CIs) for associations of cytomorphometric features with risk of subsequent BC were assessed using multivariable logistic regression. More than 55 million epithelial and 37 million stromal cells were profiled across 972 BBD images. Cytomorphometric features were individually predictive of subsequent BC risk, independently of BBD histologic classification. However, cytomorphometric features of epithelial functional/structural decline were statistically significantly predictive of low-grade but not high-grade BC following PDWA (OR for low-grade BC per 1-SD increase in nuclear area and nuclear perimeter, 2.10; 95% CI, 1.26-3.49, and 2.22; 95% CI, 1.30-3.78, respectively), whereas stromal inflammation was predictive of high-grade but not low-grade BC following NPD (OR for high-grade BC per 1-SD increase in stromal cellular density, 1.53; 95% CI, 1.13-2.08). Associations of nuclear chromasia and nuclear contour irregularity with subsequent tumor grade were context specific, with both features predicting low-grade BC risk following PDWA (OR per 1-SD, 1.58; 95% CI, 1.06-2.35, and 2.21; 95% CI, 1.25-3.91, for nuclear chromasia and nuclear contour irregularity, respectively) and high-grade BC following NPD (OR per 1-SD, 1.47; 95% CI, 1.11-1.96, and 1.29; 95% CI, 1.00-1.70, for nuclear chromasia and nuclear contour irregularity, respectively). The results indicate that cytomorphometric features on BBD hematoxylin-eosin-stained images might help to refine BC risk estimation and potentially inform BC risk reduction strategies for BBD patients, particularly those currently designated as low risk.

Spectrum of atypical ductal hyperplasia (ADH) and ductal carcinoma in-situ (DCIS): Diagnostic challenges

Breast specimens are some of the more common specimens sent to the pathology laboratory for diagnosis. From a clinical perspective, the diagnoses fall into three broad categories: benign, atypical and malignant with patients then being managed according to established guidelines. However, the pathologic diagnosis can sometimes be challenging, and the distinction between these categories is sometimes far more subtle and subjective than non-pathologist may understand. One recurring diagnostic challenge in breast pathology is the diagnosis of atypical ductal hyperplasia (ADH) versus ductal carcinoma in situ (DCIS). While many cases are straightforward, others are quite borderline and challenging to classify consistently with significant interobserver variation amongst pathologists. The distinction between ADH and DCIS is critical from a clinical management perspective because one is treated as a risk factor, and the other as a malignancy that will be completely surgically excised and may require radiation therapy. This review will address the spectrum of ADH and DCIS with the associated diagnostic challenges in the real-world setting from presentation at core needle biopsy to surgery.

Imaging Characteristics of and Multidisciplinary Management Considerations for Atypical Ductal Hyperplasia and Flat Epithelial Atypia: Review of Current Literature

High-risk lesions of the breast are frequently encountered in percutaneous biopsy specimens. While benign, these lesions have historically undergone surgical excision due to their potential to be upgraded to malignancy. However, there is emerging evidence that a tailored management approach should be considered to reduce overtreatment of these lesions. Flat epithelial atypia (FEA) and atypical ductal hyperplasia (ADH) are two of the most commonly encountered high-risk lesions. FEA has been shown to have a relatively low rate of progression to malignancy, and some guidelines are now recommending observation over routine excision in select cases. Selective observation may be reasonable in cases where the target lesion is small and completely removed at biopsy and when there are no underlying risk factors, such as a history of breast cancer or genetic mutation or concurrent ADH. ADH has the highest potential upgrade rate to malignancy of all the high-risk lesions. Most society guidelines continue to recommend surgical excision of this lesion. More recently, some literature suggests that ADH lesions that appear completely removed at biopsy, involve limited foci (less than two or three) with no necrosis or significant atypia, manifest as a small group of mammographic calcifications, or demonstrate no enhancement at MRI may be reasonable for observation. Ultimately, management of all high-risk lesions must be based on a multidisciplinary approach that considers all patient, radiologic, clinical, and histopathologic factors. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Diagnostic Pitfalls in Breast Cancer Pathology With an Emphasis on Core Needle Biopsy Specimens

CONTEXT.—

Breast pathology has many mimics and diagnostic pitfalls. Evaluation of malignant breast lesions, particularly in the biopsy setting, can be especially challenging, with diagnostic errors having significant management implications.

OBJECTIVE.—

To discuss the pitfalls encountered when evaluating ductal carcinoma in situ and invasive breast carcinomas, providing histologic clues and guidance for appropriate use and interpretation of immunohistochemistry to aid in the correct diagnosis.

DATA SOURCES.—

Data were obtained from review of pertinent literature of ductal carcinoma in situ and invasive breast carcinomas and from the experience of the authors as practicing breast pathologists.

CONCLUSIONS.—

Awareness of the pitfalls in diagnosing breast cancers is important when creating a differential diagnosis for each breast lesion evaluated. This review will cover some of these scenarios to aid in the diagnostic process.

Special Histologic Type and Rare Breast Tumors - Diagnostic Review and Clinico-Pathological Implications

Breast cancer is the most common malignant tumor in females. While most carcinomas are categorized as invasive carcinoma, no special type (NST), a diverse group of tumors with distinct pathologic and clinical features is also recognized, ranging in incidence from relatively more common to rare. So-called "special histologic type" tumors display more than 90% of a specific, distinctive histologic pattern, while a spectrum of tumors more often encountered in the salivary gland may also arise in the breast. Metaplastic carcinomas can present diagnostic challenges. Some uncommon tumors harbor pathognomonic genetic alterations. This article provides an overview of the key diagnostic points and differential diagnoses for this group of disparate lesions, as well as the salient clinical characteristics of each entity.

The role of mineralocorticoids and glucocorticoids under the impact of 11β-hydroxysteroid dehydrogenase in human breast lesions

We attempted to explore the possible involvement of the in situ availability of mineralocorticoids and mineralocorticoid receptor (MR) in the pathogenesis of mammary ductal carcinoma. We also explored their individual profiles among different subtypes of invasive ductal carcinomas of no special type (IDC-NST) by evaluating the status of MR, Glucocorticoid receptor (GR), and 11β hydroxysteroid dehydrogenase (HSD) 1/2 at each stage of the putative cascade of the mammary ductal proliferative disorders. In this study, IDC-NST, ductal carcinoma in situ (DCIS), atypical ductal hyperplasia (ADH), and non-pathological breast tissues were all evaluated by immunohistochemistry. MR was significantly lower in ADH than in DCIS or IDC-NST. 11βHSD2 was significantly lower in ADH than normal breast tissue and 11βHSD1 was significantly higher in DCIS than normal, ADH, or IDC-NST. MR in progesterone receptor (PR)-positive IDC-NST cases tended to be associated with the Ki-67 labeling index. Results of the present study demonstrated that the status of MR and GR in conjunction with the 11βHSDs was correlated with the development of low-grade proliferative disorders in mammary glands. In addition, the potential crosstalk between MR and PR could also influence cell proliferation of breast carcinoma cells but further investigations are required for clarification.

Risk factors for breast cancer development by tumor characteristics among women with benign breast disease

Background

Among women diagnosed with invasive breast cancer, 30% have a prior diagnosis of benign breast disease (BBD). Thus, it is important to identify factors among BBD patients that elevate invasive cancer risk. In the general population, risk factors differ in their associations by clinical pathologic features; however, whether women with BBD show etiologic heterogeneity in the types of breast cancers they develop remains unknown.

Methods

Using a nested case-control study of BBD and breast cancer risk conducted in a community healthcare plan (Kaiser Permanente Northwest), we assessed relationships of histologic features in BBD biopsies and patient characteristics with subsequent breast cancer risk and tested for heterogeneity of associations by estrogen receptor (ER) status, tumor grade, and size. The study included 514 invasive breast cancer cases (median follow-up of 9 years post-BBD diagnosis) and 514 matched controls, diagnosed with proliferative or non-proliferative BBD between 1971 and 2006, with follow-up through mid-2015. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using multivariable polytomous logistic regression models.

Results

Breast cancers were predominantly ER-positive (86%), well or moderately differentiated (73%), small (74% < 20 mm), and stage I/II (91%). Compared to patients with non-proliferative BBD, proliferative BBD with atypia conferred increased risk for ER-positive cancer (OR = 5.48, 95% CI = 2.14–14.01) with only one ER-negative case, P-heterogeneity = 0.45. The presence of columnar cell lesions (CCLs) at BBD diagnosis was associated with a 1.5-fold increase in the risk of both ER-positive and ER-negative tumors, with a 2-fold increase (95% CI = 1.21–3.58) observed among postmenopausal women (56%), independent of proliferative BBD status with and without atypia. We did not identify statistically significant differences in risk factor associations by tumor grade or size.

Conclusion

Most tumors that developed after a BBD diagnosis in this cohort were highly treatable low-stage ER-positive tumors. CCL in BBD biopsies may be associated with moderately increased risk, independent of BBD histology, and irrespective of ER status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01410-1.

Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast

Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.

Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast

Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.

Atypical Lesions of the Breast and Lobular Carcinoma in Situ in Pregnancy - Surgeons' Practice

Objective

Approach to precancerous and high-risk breast lesions occurring in pregnancy has received little attention in the literature. We carried out a study to investigate the practice of surgeons in the management of these cases.

Materials and Methods

A short survey was sent to surgeons, including a multiple-choice questionnaire about their practice for atypical hyperplasia or lobular carcinoma in situ presenting in each trimester of pregnancy or at time of breastfeeding. Answer options included observation, immediate vacuum biopsy, immediate surgery, surgery in next trimester, surgery after delivery, and surgery after end of breastfeeding; based on the time of presentation.

Results

Out of the 671 practitioners invited, 97(14.5 %) responded to the survey. Participants were from 23 countries. Answers showed that management of gestational Atypical Ductal Hyperplasia (ADH) and Lobular Neoplasia (LN) was readily postponed by surgeons in favor of fetus safety while being cautious about risks of conservative management alone.

Conclusion

Various methods of treatment are selected by surgeons for managing high-risk breast lesions during pregnancy. In the absence of relevant literature, decision making in a multidisciplinary team would be the best approach in these cases.

Assessment and management of B3 breast lesions with atypia: a focused review

Breast lesions with atypia are a spectra of diseases that confer increased risk of breast cancer because of an increased probability of finding concomitant cancer after excision, or evolution toward in situ or invasive cancer over the long term. The widespread use of radiologic tools and core needle breast biopsies, in recent years, has led to an increase in the diagnosis of these atypical breast lesions. Concurrent with this has been an improvement in the classification and pathogenesis of these lesions. Current evidence suggests that the recognition and treatment of patients with atypical histology after biopsy and surgical excision requires a multidisciplinary approach to decrease the overdiagnosis and overtreatment risks. This focused review investigates the controversy and current management of atypical ductal hyperplasia, lobular neoplasia, flat epithelial atypia, and intraductal papilloma with atypia along with the risk-reducing strategies.