HER2 Testing: Insights From Pathologists' Perspective on Technically Challenging HER2 FISH Cases.

OBJECTIVE: College of American Pathologists and the American Society of Clinical Oncology guidelines provide straightforward criteria for HER2 interpretation in breast carcinomas; however, a subset of cases present unusual diagnostic dilemmas. MATERIALS AND METHODS: Ten challenging HER2 fluorescence in situ hybridization (FISH) cases were selected for analysis. The study included a variety of problematic cases such as those with discordant immunohistochemistry (IHC) and FISH results, cases with high intratumoral variability in HER2 copy number, a case with a highly amplified clone in 5% to 10% of the tumor sample, and a case with tumor cells containing tightly clumped HER2 signals. Six high volume HER2 FISH laboratories performed and interpreted HER2 FISH (adding HER2 IHC if necessary). Interpretation strategies were discussed. RESULTS: There was 100% concordance between laboratories in 4/10 cases. Tumors with increased intratumoral variability (tumors with high variability in HER2 copy number per cell but which otherwise do not fulfill College of American Pathologists and the American Society of Clinical Oncology criteria for heterogeneity) exhibited 100% concordance in 3/4 cases, but 1 case had only 50% agreement. Low positive HER2 cases (group 1 cases with <6 average HER2 copies/cell) had 1 laboratory disagreeing with the majority in 4/4 cases, and this was the only category with discordance between IHC and FISH methodologies. All laboratories identified the case with heterogeneity and interpreted it as positive. Five of the 6 laboratories interpreted the case with tightly clustered HER2 signals as positive. CONCLUSIONS: This study offers specific observations and interpretation strategies that laboratories can use when confronted with difficult HER 2 cases. It then highlights communication strategies a laboratory may use to discuss these unusual HER2 results with the clinical team.

HER2 Testing Characteristics Can Predict Residual Cancer Burden following Neoadjuvant Chemotherapy in HER2-Positive Breast Cancer.

OBJECTIVES: The response to HER2-targeted neoadjuvant chemotherapy (NAC) in HER2-positive (+) breast cancer can be quantified using residual cancer burden (RCB) pathologic evaluation to predict relapse free/overall survival. However, more information is needed to characterize the relationship between patterns of HER2 testing results and response to NAC. We evaluated clinicopathologic characteristics associated with RCB categories in HER2+ patients who underwent HER2-directed NAC. METHODS: A retrospective chart review was conducted with Stage I-III HER2+ breast cancer cases following NAC and surgical resection. HER2 immunohistochemistry (IHC) staining and fluorescence in situ hybridization (FISH), histologic/clinical characteristics, hormone receptor status, and RCB scores (RCB-0, RCB-I, RCB-II, and RCB-III) were evaluated. RESULTS: 64/151 (42.4%) patients with HER2+ disease had pathologic complete response (pCR). Tumors with suboptimal response (RCB-II and RCB-III) were more likely to demonstrate less than 100% HER2 IHC 3+ staining (p < 0.0001), lower HER2 FISH copies (p < 0.0001), and lower HER2/CEP17 ratios (p = 0.0015) compared to RCB-I and RCB-II responses. Estrogen receptor classification using ≥10% versus ≥1% staining showed greater association with higher RCB categories. CONCLUSIONS: HER2+ characteristics show differing response to therapy despite all being categorized as positive; tumors with less than 100% IHC 3+ staining, lower HER2 FISH copies, and lower HER2/CEP17 ratios resulted in higher RCB scores.

Effects of Germline Pathogenic Variants, Cancer Subtypes, Tumor-related Characteristics, and Pregnancy-associated Diagnosis on Outcomes.

BACKGROUND: Although breast cancer (BC) is uncommon in women age ≤ 35 years, women in this age group may have more aggressive cancer subtypes and high-risk pathogenic variants (HRPVs). Higher recurrence and mortality rates in young patients may be related to differences in tumor biology, pathologic mutation status, or treatment. The purpose of this study was to evaluate germline mutation status and other factors that affect recurrence-free survival (RFS) and overall survival (OS) in young women with BC. MATERIALS AND METHODS: This was a retrospective study of women diagnosed with BC at age ≤ 35 years at Allina Health System from 2000 through 2017 (n = 306). Information was collected on germline mutation status, tumor characteristics (grade, hormone receptor, and human epidermal growth factor receptor 2), molecular subtype, pregnancy-associated cancers, and treatment. Survival analyses using Kaplan-Meier curves were conducted for RFS and OS. RESULTS: With mean follow-up of 6.5 years, OS was 87.0% for invasive cancers, RFS was 84.7%; 69% obtained genetic testing, and 26.9% had HRPVs. There were no differences in RFS or OS between patients with HRPV versus unknown/low/moderate risk variants. Recurrence analysis showed increased recurrence rates in luminal B-like cancers followed by triple negative and human epidermal growth factor receptor 2-positive cancers (P = .041). Pregnancy-associated BC diagnoses, angiolymphatic invasion, and tumor stage were associated with reduced OS. In spite of young age at diagnosis, nearly one-third of patients did not receive germline genetic testing. CONCLUSIONS: Similar survival patterns were found between women with HRPV versus no known mutations. Luminal B-like subtype, pregnancy-associated BC, angiolymphatic invasion, and cancer stage were associated with reduced OS.

Clinicopathologic analysis of a large series of microinvasive breast cancers.

Clinical management of microinvasive breast cancer (Tmic) remains controversial. Although metastases are infrequent in Tmic carcinoma patients, surgical treatment typically includes lymph node sampling. The objective of this study was to determine the rate and predictors of lymph node metastases, recurrence, and survival in a large series of Tmic breast carcinomas. Consecutive cases of Tmic were identified within our health care system from 2001 to 2015. We reviewed results of lymph node sampling and other pathologic factors including hormone receptor/HER2 status, associated in situ tumor size/grade, margin status, number of invasive foci, surgical/adjuvant therapies, and recurrence/survival outcomes. In this cohort, 294 Tmic cases were identified with mean follow-up of 4.6 years. Of 260 patients who underwent axillary staging, lymph node metastases were identified in 1.5% (all of which were ductal type). All Tmic cases with positive lymph node metastases had associated DCIS with size > 5 cm (5.3-8.5 cm) compared to a median DCIS tumor size of 2.5 cm (0.2-19.0 cm) for the entire cohort. No lymph node metastases were seen with microinvasive lobular carcinoma. During the follow-up period, there were no regional/distant recurrences or breast cancer-associated deaths in a mean follow-up period of 4.6 years. Two patients developed subsequent ipsilateral breast cancer (DCIS) in a different quadrant than the original Tmic. Clinical behavior of microinvasive breast cancer in this series is similar to DCIS. Lymph node metastases are uncommon and were only seen with ductal type microinvasive carcinoma. Our data suggest limited benefit for routine node sampling and support management of Tmic similar to DCIS, particularly for patients with DCIS < 5 cm in size.

Utility of Oncotype DX Risk Assessment in Patients With Invasive Lobular Carcinoma.

INTRODUCTION/BACKGROUND: Oncotype DX (Genomic Health, Redwood City, CA) uses reverse transcriptase polymerase chain reaction analysis to measure tumor gene expression for determining recurrence risk (RR) and guiding chemotherapy decisions for breast cancer patients. Invasive lobular carcinoma (ILC) is a histologic subtype that has not been the focus of prior studies validating Oncotype DX. The study purpose was to develop a model using histologic tumor characteristics to predict uniformly low Oncotype DX Recurrence Scores (RS) in ILC. PATIENTS AND METHODS: ILC cases in our pathology database with Oncotype DX testing were identified. Histologic tumor characteristics, immunohistochemical (IHC) of estrogen receptor (ER)/progesterone receptor (PgR) percent, HER2, E-cadherin expression, and Ki-67 levels were obtained for cases. Discriminant analysis was used to test the hypothesis that tumors classified as lower/higher risk based on Oncotype DX RS would differ significantly on a linear combination of variables. RESULTS: From 2006 - 2014, 158 cases of ILC having Oncotype DX testing were identified; 90 low risk (RS < 18), 66 intermediate risk (RS 18 - 30) and 2 high risk (RS > 30). Discriminant analysis showed that PgR% followed by Ki-67 provided the greatest contribution to discern low versus elevated RS. A subset of 57 cases (∼36%) with predicted probabilities > 86% for either low or high RS yielded 96.5% correct classification, 92.3% sensitivity, and 97.7% specificity. CONCLUSION: Our analytical model may be useful in predicting lower RR in patients with ILC. If validated, this provides a faster and less expensive alternative to Oncotype DX testing in certain patients with ILC.

Red blood cell transfusion practices: a College of American Pathologists Q-Probes study of compliance with audit criteria in 128 hospitals.

CONTEXT: Most information on compliance with audit criteria for red blood cell (RBC) transfusions comes from single institutions; few studies have compared practices among many hospitals. OBJECTIVE: To survey a cross-section of hospitals in 2008 for criteria and compliance with RBC transfusion guidelines, using the College of American Pathologists Q-Probes format. DESIGN: One hundred twenty-eight hospitals, representing about 4.5% (724,332 of 16,212,000) of all annual RBC usage in the United States, provided information on their RBC audit practices and their recent rates of compliance. They also each examined 50 RBC transfusion episodes for compliance with their guidelines. RESULTS: The participants' median, pretransfusion hemoglobin thresholds for audit review were 8.0 to 8.9 g/dL for most clinical settings and 9.0 to 9.9 g/dL for patients with underlying cardiopulmonary disease. For the transfusion episodes examined, 60% (2063 of 6518) were for a single unit. The median of the institutional averages for pretransfusion hemoglobin was 8.1 g/dL, and the median rate of compliance was 69% (range, 0%-100%). Involvement by a pathologist or transfusion medicine expert in the audit system was associated with more-strict audit criteria and better compliance. CONCLUSIONS: Median hemoglobin thresholds for RBC transfusion audits were somewhat higher than currently evolving recommendations, but opportunities for improvement were provided by expert involvement and by the growing frequency of 1-unit transfusions.

Achieving 95% cross-methodological concordance in HER2 testing: causes and implications of discordant cases.

We were interested in determining our concordance between fluorescence in situ hybridization (FISH) and a previously validated immunohistochemical HER2 assay to identify possible reasons for discordance and to determine if all reasons for discordance were addressed by the American Society of Clinical Oncology/College of American Pathologists guidelines. We reviewed 697 cases (2004-2007) in which HER2 immunohistochemical and FISH testing were concurrently done. Overall concordance between nonequivocal immunohistochemical and FISH results was 96%. Of the 19 discordant cases, 13 (68%) were interpreted as positive immunohistochemically but negative by FISH. The primary reason for this discordance was immunohistochemical interpretation. Weak stain intensity, granular staining, and interpretation in areas of crush artifact were identified as the most common issues. Of the 6 cases interpreted as immunohistochemically negative and FISH-positive, 2 were from patients known to be receiving trastuzumab at the time of biopsy, 1 was very close to the FISH equivocal category, and 4 cases had fewer than 1.5 CEP17 signals per cell (1 patient in this group was also receiving trastuzumab). Focusing on issues with HER2 immunohistochemical interpretation can improve concordance rates for immunohistochemically positive cases, but biologic reasons may explain some discordant immunohistochemically negative cases.

Blood bank safety practices: mislabeled samples and wrong blood in tube--a Q-Probes analysis of 122 clinical laboratories.

CONTEXT: Although a rare occurrence, ABO incompatible transfusions can cause patient morbidity and mortality. Up to 20% of all mistransfusions are traced to patient misidentification and/or sample mislabeling errors that occur before a sample arrives in the laboratory. Laboratories play a significant role in preventing mistransfusion by identifying wrong blood in tube and rejecting mislabeled samples. OBJECTIVES: To determine the rates of mislabeled samples and wrong blood in tube for samples submitted for ABO typing and to survey patient identification and sample labeling practices and sample acceptance policies for ABO typing samples across a variety of US institutions. DESIGN: One hundred twenty-two institutions prospectively reviewed inpatient and outpatient samples submitted for ABO typing for 30 days. Labeling error rates were calculated for each participant and tested for associations with institutional demographic and practice variable information. Wrong-blood-in-tube rates were calculated for the 30-day period and for a retrospective 12-month period. A concurrent survey collected institution-specific sample labeling requirements and institutional policies regarding the fate of mislabeled samples. RESULTS: For all institutions combined, the aggregate mislabeled sample rate was 1.12%. The annual and 30-day wrong-blood-in-tube aggregate rates were both 0.04%. Patient first name, last name, and unique identification number were required on the sample by more than 90% of participating institutions; however, other requirements varied more widely. CONCLUSIONS: The rates of mislabeled samples and wrong blood in tube for US participants in this study were comparable to those reported for most European countries. The survey of patient identification and sample labeling practices and sample acceptance policies for ABO typing samples revealed both practice uniformity and variability as well as significant opportunity for improvement.

Laboratory compliance with the American Society of Clinical Oncology/college of American Pathologists guidelines for human epidermal growth factor receptor 2 testing: a College of American Pathologists survey of 757 laboratories.

CONTEXT: To ensure quality human epidermal growth receptor 2 (HER2) testing in breast cancer, the American Society of Clinical Oncology/College of American Pathologists guidelines were introduced with expected compliance by 2008. OBJECTIVE: To assess the effect these guidelines have had on pathology laboratories and their ability to address key components. DESIGN: In late 2008, a survey was distributed with the HER2 immunohistochemistry (IHC) proficiency testing program. It included questions regarding pathology practice characteristics and assay validation using fluorescence in situ hybridization or another IHC laboratory assay and assessed pathologist HER2 scoring competency. RESULTS: Of the 907 surveys sent, 757 (83.5%) were returned. The median laboratory accessioned 15 000 cases and performed 190 HER2 tests annually. Quantitative computer image analysis was used by 33% of laboratories. In-house fluorescence in situ hybridization was performed in 23% of laboratories, and 60% of laboratories addressed the 6- to 48-hour tissue fixation requirement by embedding tissue on the weekend. HER2 testing was performed on the initial biopsy in 40%, on the resection specimen in 6%, and on either in 56% of laboratories. Testing was validated with only fluorescence in situ hybridization in 47% of laboratories, whereas 10% of laboratories used another IHC assay only; 13% used both assays, and 12% and 15% of laboratories had not validated their assays or chose "not applicable" on the survey question, respectively. The 90% concordance rate with fluorescence in situ hybridization results was achieved by 88% of laboratories for IHC-negative findings and by 81% of laboratories for IHC-positive cases. The 90% concordance rate for laboratories using another IHC assay was achieved by 80% for negative findings and 75% for positive cases. About 91% of laboratories had a pathologist competency assessment program. CONCLUSIONS: This survey demonstrates the extent and characteristics of HER2 testing. Although some American Society of Clinical Oncology/College of American Pathologists guidelines have been implemented, gaps remain in validation of HER2 IHC testing.

Canalicular adenoma arising in the esophagus.

Canalicular adenomas are benign neoplasms that arise from salivary glands and often present as painless enlarging nodules. They have a predilection for upper lip but can be found throughout the oropharynx. To our knowledge, canalicular adenoma arising in the esophagus has never been described in the English literature. Here we report a canalicular adenoma occurring in the esophagus.

Integration of scanned document management with the anatomic pathology laboratory information system: analysis of benefits.

Electronic document management systems (EDMSs) have the potential to improve the efficiency of anatomic pathology laboratories. We implemented a novel but simple EDMS for scanned documents as part of our laboratory information system (AP-LIS) and collected cost-benefit data with the intention of discerning the value of such a system in general and whether integration with the AP-LIS is advantageous. We found that the direct financial benefits are modest but the indirect and intangible benefits are large. Benefits of time savings and access to data particularly accrued to pathologists and residents (3.8 h/d saved for 26 pathologists and residents). Integrating the scanned document management system (SDMS) into the AP-LIS has major advantages in terms of workflow and overall simplicity. This simple, integrated SDMS is an excellent value in a practice like ours, and many of the benefits likely apply in other practice settings.