Reflex Repeat HER2 Testing of Grade 3 Breast Carcinoma at Excision Using Immunohistochemistry and In Situ Analysis: Frequency of HER2 Discordance and Utility of Core Needle Biopsy Parameters to Refine Case Selection

Decoding the molecular subtypes of breast cancer seen on multimodal ultrasound images using an assembled convolutional neural network model: A prospective and multicentre study

Background

Preoperative determination of breast cancer molecular subtypes facilitates individualized treatment plan-making and improves patient prognosis. We aimed to develop an assembled convolutional neural network (ACNN) model for the preoperative prediction of molecular subtypes using multimodal ultrasound (US) images.

Methods

This multicentre study prospectively evaluated a dataset of greyscale US, colour Doppler flow imaging (CDFI), and shear-wave elastography (SWE) images in 807 patients with 818 breast cancers from November 2016 to February 2021. The St. Gallen molecular subtypes of breast cancer were confirmed by postoperative immunohistochemical examination. The monomodal ACNN model based on greyscale US images, the dual-modal ACNN model based on greyscale US and CDFI images, and the multimodal ACNN model based on greyscale US and CDFI as well as SWE images were constructed in the training cohort. The performances of three ACNN models in predicting four- and five-classification molecular subtypes and identifying triple negative from non-triple negative subtypes were assessed and compared. The performance of the multimodal ACNN was also compared with preoperative core needle biopsy (CNB).

Finding

The performance of the multimodal ACNN model (macroaverage area under the curve [AUC]: 0.89–0.96) was superior to that of the dual-modal ACNN model (macroaverage AUC: 0.81–0.84) and the monomodal ACNN model (macroaverage AUC: 0.73–0.75) in predicting four-classification breast cancer molecular subtypes, which was also better than that of preoperative CNB (AUC: 0.89–0.99 vs. 0.67–0.82, p < 0.05). In addition, the multimodal ACNN model outperformed the other two ACNN models in predicting five-classification molecular subtypes (AUC: 0.87–0.94 vs. 0.78-0.81 vs. 0.71–0.78) and identifying triple negative from non-triple negative breast cancers (AUC: 0.934–0.970 vs. 0.688–0.830 vs. 0.536–0.650, p < 0.05). Moreover, the multimodal ACNN model obtained satisfactory prediction performance for both T1 and non-T1 lesions (AUC: 0.957–0.958 and 0.932–0.985).

Interpretation

The multimodal US-based ACNN model is a potential noninvasive decision-making method for the management of patients with breast cancer in clinical practice.

Funding

This work was supported in part by the National Natural Science Foundation of China (Grants 81725008 and 81927801), Shanghai Municipal Health Commission (Grants 2019LJ21 and SHSLCZDZK03502), and the Science and Technology Commission of Shanghai Municipality (Grants 19441903200, 19DZ2251100, and 21Y11910800).

Estrogen Receptor, Progesterone Receptor, and Human Epidermal Growth Factor Receptor-2 Testing in Breast Cancer: Assessing the Value of Repeated Centralized Testing in Excision Specimens

At some tertiary breast care centers, where many patients are referred from other institutions, it is routine to repeat testing for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2/neu) in excision specimens if these tests were performed on the preceding biopsy at the referring facility. The goal of this study is to assess the value of this practice. We documented results from ER, PR, and HER2 testing in 541 consecutive invasive breast cancers excised over a 2.5-year period and analyzed the subset (n=153) for which testing was performed on the excision specimen solely due to the fact that testing on the preceding biopsy was performed at an outside institution. The rates and directions of biopsy-to-excision change were as follows: ER [1.3% (2/153), 100% from (+) to (-)]; PR [4% (6/153), 83% from (+) to (-)]; HER2/neu assessed by immunohistochemistry [21% (29/137)]; HER2/neu assessed by fluorescence in situ hybridization [3.3% (2/61); 50% from amplified to nonamplified and 50% vice versa]. There were no ER(-) and PR(-) biopsy cases that became ER and/or PR(+) in the excision. By coordinate analysis for the hormone receptors [ie, ER and/or PR(+) being indicative of "hormone receptor" (HR) positivity], there were no cases that changed from HR(+) in the biopsy to HR(-) in the excision (or vice versa), which suggests that repeat testing for ER and PR in this setting is of limited value. In an analysis that incorporated both immunohistochemistry and in situ fluorescence hybridization results, there were 2 cases with a clinically significant biopsy-to-excision change in HER2/neu status in which that change was detected primarily because the excision was retested. These findings provide baseline data for formulating policies on whether repeat testing should routinely be performed in the described scenario.

Impact of the 2018 ASCO/CAP HER2 Guideline Focused Update

OBJECTIVES

The 2018 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) human epidermal growth factor receptor 2 (HER2) guideline focused update revises the HER2 scoring criteria. We evaluated the impact on HER2 rates in breast carcinoma diagnosed at our center.

METHODS

In a retrospective series of breast core biopsies with invasive carcinoma diagnosed between 2014 and 2017 (n = 1,350), HER2 status was classified according to 2013 and 2018 ASCO/CAP guidelines and changes in HER2 status identified.

RESULTS

The 2018 guidelines reclassified the HER2 status of 6% of patients. Most changed from HER2 equivocal status (equivocal by immunohistochemistry and fluorescence in situ hybridization under the 2013 guidelines) to HER2-negative status (2018 guidelines). The HER2-positive rate decreased by 0.4%.

CONCLUSIONS

The 2018 guidelines decrease the rate of HER2 equivocal and positive breast cancer and reduce repeat HER2 testing on excision specimens. Approximately 0.4% of patients will become newly ineligible for anti-HER2 therapy.

Utility of Human Epidermal Growth Factor Receptor 2 (HER2) Retesting of Histologic Grade 3 Invasive Breast Carcinomas

BACKGROUND

American Society of Clinical Oncology and College of American Pathologists guidelines recommend repeated evaluation of human epidermal growth factor receptor 2 (HER2) status on surgical specimens from patients with a diagnosis by core-needle biopsy of Grade 3, HER2-negative invasive tumors of the breast. However, there are limited data to support reflexive testing.

OBJECTIVE

To evaluate the utility of HER2 retesting of histologic Grade 3, HER2-negative invasive breast carcinomas.

METHODS

We evaluated 78 patients from Kaiser Permanente East Bay in whom Grade 3, HER2-negative invasive breast carcinoma was diagnosed between 2015 and 2017 by core biopsy, to compare HER2 status on core biopsy vs excisional biopsy specimen. The HER2 status was determined by immunohistochemistry, fluorescent in situ hybridization, or both. All patients were retested for HER2 status on surgical specimen according to the aforementioned guidelines. Recipients of neoadjuvant chemotherapy were excluded.

RESULTS

One of the 78 patients demonstrated negative-to-positive status discordance between core biopsy and surgical specimens and was treated with trastuzumab. One patient was HER2 negative by core biopsy and was HER2 equivocal by immunohistochemical and fluorescent in situ hybridization evaluation of the surgical specimen. Seventy-six patients demonstrated concordant HER2 status between core biopsy and surgical specimens.

CONCLUSION

The rate of clinically significant HER2 status discordance between core biopsy and surgical specimens in patients with Grade 3 breast carcinoma is low. However, given the dramatically improved survival conferred by trastuzumab therapy, our findings support reflex HER2 testing of surgical specimens for patients with core biopsy-diagnosed HER2-negative breast carcinoma.

Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer: American Society of Clinical Oncology/College of American Pathologists Clinical Practice Guideline Focused Update

PURPOSE.—

To update key recommendations of the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) human epidermal growth factor receptor 2 (HER2) testing in breast cancer guideline.

METHODS.—

Based on the signals approach, an Expert Panel reviewed published literature and research survey results on the observed frequency of less common in situ hybridization (ISH) patterns to update the recommendations.

RECOMMENDATIONS.—

Two recommendations addressed via correspondence in 2015 are included. First, immunohistochemistry (IHC) 2+ is defined as invasive breast cancer with weak to moderate complete membrane staining observed in >10% of tumor cells. Second, if the initial HER2 test result in a core needle biopsy specimen of a primary breast cancer is negative, a new HER2 test may (not "must") be ordered on the excision specimen based on specific clinical criteria. The HER2 testing algorithm for breast cancer is updated to address the recommended workup for less common clinical scenarios (approximately 5% of cases) observed when using a dual-probe ISH assay. These scenarios are described as ISH group 2 ( HER2/chromosome enumeration probe 17 [CEP17] ratio ≥2.0; average HER2 copy number <4.0 signals per cell), ISH group 3 ( HER2/CEP17 ratio <2.0; average HER2 copy number ≥6.0 signals per cell), and ISH group 4 ( HER2/CEP17 ratio <2.0; average HER2 copy number ≥4.0 and <6.0 signals per cell). The diagnostic approach includes more rigorous interpretation criteria for ISH and requires concomitant IHC review for dual-probe ISH groups 2 to 4 to arrive at the most accurate HER2 status designation (positive or negative) based on combined interpretation of the ISH and IHC assays. The Expert Panel recommends that laboratories using single-probe ISH assays include concomitant IHC review as part of the interpretation of all single-probe ISH assay results.

Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer: American Society of Clinical Oncology/College of American Pathologists Clinical Practice Guideline Focused Update

Purpose To update key recommendations of the American Society of Clinical Oncology/College of American Pathologists human epidermal growth factor receptor 2 (HER2) testing in breast cancer guideline. Methods Based on the signals approach, an Expert Panel reviewed published literature and research survey results on the observed frequency of less common in situ hybridization (ISH) patterns to update the recommendations. Recommendations Two recommendations addressed via correspondence in 2015 are included. First, immunohistochemistry (IHC) 2+ is defined as invasive breast cancer with weak to moderate complete membrane staining observed in > 10% of tumor cells. Second, if the initial HER2 test result in a core needle biopsy specimen of a primary breast cancer is negative, a new HER2 test may (not "must") be ordered on the excision specimen based on specific clinical criteria. The HER2 testing algorithm for breast cancer is updated to address the recommended work-up for less common clinical scenarios (approximately 5% of cases) observed when using a dual-probe ISH assay. These scenarios are described as ISH group 2 ( HER2/chromosome enumeration probe 17 [CEP17] ratio ≥ 2.0; average HER2 copy number < 4.0 signals per cell), ISH group 3 ( HER2/CEP17 ratio < 2.0; average HER2 copy number ≥ 6.0 signals per cell), and ISH group 4 ( HER2/CEP17 ratio < 2.0; average HER2 copy number ≥ 4.0 and < 6.0 signals per cell). The diagnostic approach includes more rigorous interpretation criteria for ISH and requires concomitant IHC review for dual-probe ISH groups 2 to 4 to arrive at the most accurate HER2 status designation (positive or negative) based on combined interpretation of the ISH and IHC assays. The Expert Panel recommends that laboratories using single-probe ISH assays include concomitant IHC review as part of the interpretation of all single-probe ISH assay results. Find additional information at www.asco.org/breast-cancer-guidelines .

Concordance of immunohistochemistry between core needle biopsy and surgical resection of breast cancer

Background/aim: The purpose of this study was to evaluate the concordance of immunohistochemical (IHC) parameters of breast lesions between the core needle biopsy (CNB) and the surgical resection specimen. Materials and methods: CNB and resection specimens of female patients were retrospectively analyzed. ER, PR, HER-2, and Ki-67 parameters were compared for each patient. A total of 284 cases were assessed. Forty-one and 48 cases were excluded from the HER-2 and Ki-67 examinations, respectively, because the CNBs did not allow for IHC. Results: Concordance rates were 93.3% for ER, 89.4% for PR, 90.1% for HER-2, and 80.9% for Ki-67.Conclusion: CNB is accurate for the evaluation of the surrogate molecular profile of invasive breast cancer despite the heterogeneity of tumors.

Evaluation of Discordance in Primary Tumor and Lymph Node Response After Neoadjuvant Therapy in Breast Cancer

BACKGROUND

Neoadjuvant therapy (NAT) offers a unique opportunity to assess tumor response to systemic agents. However, a discrepancy may exist between the response of the primary tumor and involved nodes. We report on the frequency of response discordance after NAT in breast cancer.

PATIENTS AND METHODS

All consecutive node-positive patients receiving NAT in our department from 2009 to 2014 were identified. Patient demographics, and radiologic and pathologic features were tabulated. Tumor response was estimated by magnetic resonance imaging of the breast. Lymph node (LN) response was estimated from pathologic treatment response measurements. Statistical analysis was performed.

RESULTS

A total of 108 node-positive patients treated with NAT were eligible for inclusion. Median age was 51.73 years (range, 20-87 years). All patients underwent axillary clearance, and 62% underwent mastectomy. A 40% mean reduction in tumor size was observed. Statistically, a positive correlation between tumor and LN response after NAT was observed (Spearman correlation coefficient, r = 0.46, P < .001). Complete pathologic response was observed in 17 patients (15.7%). However, 21 patients experienced complete LN response, with only 81% of these patients (n = 17) experiencing a complete response in tumor also. A complete response was observed in tumor in 20 patients, and this predicted complete nodal response in 85% of cases (n = 17). Fifteen percent of primary tumors with complete pathologic response had persistently positive LNs.

CONCLUSION

A significant discordance exists between the primary tumor and LN response, representing a concern for the lack of response of occult regional or systemic metastases due to potential biologic heterogeneity.