Clinical and molecular characteristics of HER2-low-positive breast cancer: pooled analysis of individual patient data from four prospective, neoadjuvant clinical trials.

BACKGROUND: The development of anti-HER2 antibody-drug conjugates opens new therapeutic options for patients with breast cancer, including patients with low expression of HER2. To characterise this new breast cancer subtype, we have compared the clinical and molecular characteristics of HER2-low-positive and HER2-zero breast cancer, including response to neoadjuvant chemotherapy and prognosis. METHODS: In this pooled analysis of individual patient data, we evaluated a cohort of 2310 patients with HER2-non-amplified primary breast cancer that were treated with neoadjuvant combination chemotherapy in four prospective neoadjuvant clinical trials (GeparSepto, NCT01583426; GeparOcto, NCT02125344; GeparX, NCT02682693; Gain-2 neoadjuvant, NCT01690702) between July 30, 2012, and March 20, 2019. Central HER2 testing was done prospectively before random assignment of participants in all trials. HER2-low-positive status was defined as immunohistochemistry (IHC) 1+ or IHC2+/in-situ hybridisation negative and HER2-zero was defined as IHC0, based on the American Society of Clinical Oncology/College of American Pathologists guidelines. Disease-free survival and overall survival data were available for 1694 patients (from all trials except GeparX) with a median follow-up of 46·6 months (IQR 35·0-52·3). Bivariable and multivariable logistic regression models and Cox-proportional hazards models were performed based on a predefined statistical analysis plan for analysis of the endpoints pathological complete response, disease-free survival, and overall survival. FINDINGS: A total of 1098 (47·5%) of 2310 tumours were HER2-low-positive and 1212 (52·5%) were HER2-zero. 703 (64·0%) of 1098 patients with HER2-low-positive tumours were hormone receptor positive, compared with 445 (36·7%) of 1212 patients with HER2-zero tumours (p<0.0001). HER2-low-positive tumours had a significantly lower pathological complete response rate than HER2-zero tumours (321 [29·2%] of 1098 vs 473 [39·0%] of 1212, p=0·0002). Pathological complete response was also significantly lower in HER2-low-positive tumours versus HER2-zero tumours in the hormone receptor-positive subgroup (123 [17·5%] of 703 vs 105 [23·6%] of 445, p=0·024), but not in the hormone receptor-negative subgroup (198 [50·1%] of 395 vs 368 [48·0%] of 767, p=0·21). Patients with HER2-low-positive tumours had significantly longer survival than did patients with HER2-zero tumours (3-year disease-free survival: 83·4% [95% CI 80·5-85·9] vs 76·1% [72·9-79·0]; stratified log-rank test p=0·0084; 3-year overall survival: 91·6% [84·9-93·4] vs 85·8% [83·0-88·1]; stratified log-rank test p=0·0016). Survival differences were also seen in patients with hormone receptor-negative tumours (3-year disease-free survival: 84·5% [95% CI 79·5-88·3] vs 74·4% [70·2-78.0]; stratified log-rank test p=0·0076; 3-year overall survival: 90·2% [86·0-93·2] vs 84·3% [80·7-87·3], stratified log-rank test p=0·016), but not in patients with hormone receptor-positive tumours (3-year disease-free survival 82·8% [79·1-85·9] vs 79·3% [73·9-83·7]; stratified log-rank test p=0·39; 3-year overall survival 92·3% [89·6-94·4] vs 88·4% [83·8-91·8]; stratified log-rank test p=0·13). INTERPRETATION: Our results show that HER2-low-positive tumours can be identified as new subgroup of breast cancer by standardised IHC, distinct from HER2-zero tumours. HER2-low-positive tumours have a specific biology and show differences in response to therapy and prognosis, which is particularly relevant in therapy-resistant, hormone receptor-negative tumours. Our results provide a basis for a better understanding of the biology of breast cancer subtypes and the refinement of future diagnostic and therapeutic strategies. FUNDING: German Cancer Aid (Deutsche Krebshilfe).

[Quality assurance in diagnostic in situ hybridization-experience of QuIP]. / Qualitätssicherung in der diagnostischen In-situ-Hybridisierung ­ Erfahrungen der QuIP.

The Quality Assurance Initiative Pathology (QuIP) gives pathologists the opportunity to check the methodological processes of immunohistological and molecular diagnostics in a result-oriented manner and obtain a certificate reflecting the quality. For in situ hybridization (ISH), 5 round robin tests were organized in 2019, two recurrent (HER2-ISH gastric carcinomas and HER2-ISH breast carcinomas) and three prototypical (ROS1-NSCLC, ALK1-NSCLC, NTRK). The different round robin tests, which were provided by QuIP, are based on the development in diagnostics and the importance of the therapeutic relevance of the molecules which are tested. The results of the round robin tests in 2019 showed a sensitivity of at least 94.4%, a specificity of at least 96.6%, and a success rate of 85-99%. This reflected the high standard of quality of the round robin test and the participating institutes.

Trastuzumab and survival of patients with metastatic breast cancer.

INTRODUCTION: Prognosis of Her2-positive breast cancer has changed since the introduction of trastuzumab for treatment in metastatic and early breast cancer. It was described to be even better compared to prognosis of Her2-negative metastatic breast cancer. The purpose of this study was to evaluate the effect of trastuzumab in our cohort. Besides the effect of adjuvant pretreatment with trastuzumab on survival of patients with metastatic Her2-positive breast cancer was analyzed. METHODS: All patients with primary breast cancer of the Regional Breast Cancer Center Dresden diagnosed during the years 2001-2013 were analyzed for treatment with or without trastuzumab in the adjuvant and in the metastatic treatment setting using Kaplan-Meier survival estimation and Cox regression. Age and tumor stage at time of first diagnosis of breast cancer as well as hormone receptor status, grading, time, and site of metastasis at first diagnosis of distant metastatic disease were analyzed. RESULTS: Of 4.481 female patients with primary breast cancer, 643 presented with metastatic disease. Her2-positive status was documented in 465 patients, including 116 patients with primary or secondary metastases. Median survival of patients with Her2-positive primary metastatic disease was 3.0 years (95% CI 2.3-4.0). After adjustment for other factors, survival was better in patients with Her2-positive breast cancer with trastuzumab therapy compared to Her2-negative metastatic disease (HR 2.10; 95% CI 1.58-2.79). Analysis of influence of adjuvant therapy with and without trastuzumab by Kaplan-Meier showed a trend for better survival in not pretreated patients. Median survival was highest in hormone receptor-positive Her2-positive (triple-positive) primary metastatic breast cancer patients with 3.3 years (95% CI 2.3-4.6). CONCLUSION: Prognosis of patients with Her2-positive metastatic breast cancer after trastuzumab treatment is more favorable than for Her2-negative breast cancer. The role of adjuvant chemotherapy with or without trastuzumab warrants further research. Survival is best in triple-positive metastatic breast cancer. This will effect counseling at the time of first diagnosis of metastatic breast cancer.

Correction: Diagnostic Benefit of the Detection of Mitotic Figures in Endometriotic Lesions.

[This corrects the article DOI: 10.1055/a-1580-0601.].

Diagnostic Benefit of the Detection of Mitotic Figures in Endometriotic Lesions.

Objectives Endometriosis is a chronic disease which is diagnosed by surgical intervention combined with a histological work-up. Current international and national recommendations do not require the histological determination of the proliferation rate. The diagnostic and clinical importance of the mitotic rate in endometriotic lesions still remains to be elucidated. Methods In this retrospective study, the mitotic rates and clinical data of 542 patients with histologically diagnosed endometriosis were analyzed. The mean patient age was 33.5 ± 8.0 (17 - 72) years, and the mean reproductive lifespan was 21.2 ± 7.8 (4 - 41) years. Patients were divided into two groups and patients' reproductive history and clinical endometriosis characteristics were compared between groups. The study group consisted of women with confirmed mitotic figures (n = 140, 25.83%) and the control group comprised women without proliferative activity according to their mitotic rates (n = 402, 74.27%). Results Women with endometriotic lesions and histologically confirmed mitotic figures were significantly more likely to have a higher endometriosis stage (p = 0.001), deep infiltrating endometriosis (p < 0.001), ovarian endometrioma (p = 0.012), and infertility (p = 0.049). A mitotic rate > 0 was seen significantly less often in cases with incidental findings of endometriosis (p = 0.031). The presence of symptoms and basic characteristics such as age, age at onset of menarche, reproductive lifespan and parity did not differ between the group with and the group without mitotic figures. Conclusion This study shows that a simple histological assessment of the mitotic rate offers additional diagnostic value for the detection of advanced stages of endometriosis. The possible role as a predictive marker for the recurrence of endometriosis or the development of endometriosis-associated cancer will require future study.